3D Printer Thread Manufacturing From Microplastics Recovered From the Ocean

3D Printer Thread Manufacturing From Microplastics Recovered From the Ocean | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article 3D Printer Thread Manufacturing From Microplastics Recovered From the Ocean María Yoldi Sanguesa, Lucía Grijalvo Fernández, Silvia Jiménez Herrera This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8709326/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Marine microplastic (MP) pollution represents a pervasive environmental crisis, necessitating scalable and economic remediation strategies. This study demonstrates a “Zero Plastic” circular economy model by integrating the Active Marine Microplastic Remediation System (AMMRS) into the logistics of commercial shipping vessels. This passive filtration technology was utilized to recover MPs from the Mediterranean Sea, which were then characterized and repurposed into functional 3D printing filaments. Characterization via ATR-FTIR and DSC revealed a material profile dominated by Polyethylene (PE) and Polypropylene (PP), constituting 70 to 80% of the recovered mass. A multi-stage mechanical recycling workflow, comprising densifying, crushing, and extrusion, was developed to transform these degraded marine polymers into standardized threads. Despite the prevalence of PLA and PETG in the 3D printing market, our findings validate that recycled marine PE and PP offer a highly economic and technically viable alternative. The feasibility of this circular approach was confirmed by the successful production of various functional prototypes, including industrial pins and aesthetic accessories, using a standard FDM printer (Flashforge Adventurer 5M). This research provides a tangible blueprint for turning ocean waste into industrial feedstock, supporting both marine conservation and sustainable additive manufacturing. Physical sciences/Engineering Earth and environmental sciences/Environmental sciences Physical sciences/Materials science Marine microplastics AMMRS 3D printing filament mechanical recycling Mediterranean Sea polyethylene polypropylene circular economy Figures Figure 1 Figure 2 Highlights Integration of AMMRS passive filtration into commercial shipping logistics for efficient MP recovery. Characterization of recovered Mediterranean MPs reveals a dominant profile of PE and PP (70-80%). Successful conversion of mixed marine microplastics into 3D printer thread through a multi-stage mechanical recycling process. Validation of polymer purity and degradation levels using ATR-FTIR and DSC . Demonstration of PE and PP , which constitute 70-80% of recovered marine microplastics , as an economic and viable alternative to virgin PLA/PETG filaments. Validation of the recycling workflow through the successful 3D printing of functional prototypes (pins, keyrings, and jewellery) using the recovered marine feedstock. 1 Introduction 1.1 3D printing filaments The most used 3D printing filaments are PLA (easy to use, decorative), PETG (durable, versatile), ABS/ASA (strong, functional), and TPU (flexible). Technical materials such as nylon, polycarbonate, and composites with carbon fibre or fiberglass are also noteworthy for increased rigidity and industrial applications. The choice depends on whether ease of printing (PLA), mechanical strength (ABS/Nylon), or flexibility (TPU) is required. Based on these ideas, the key points of any of them are: PLA (Polylactic Acid) : The most popular and easiest to use, ideal for prototypes, models, and educational purposes. It typically does not require a heated bed. PETG (Polyethylene Terephthalate Glycolyzed) : Excellent balance, mechanically and chemically resistant, more durable than PLA, and easy to print. ABS (Acrylonitrile Butadiene Styrene) : Very resistant to impacts and high temperatures. Common in automotive and electronics, but complex to print due to warping. ASA (Acrylonitrile Styrene Acrylate) : Like ABS but with greater resistance to weathering and UV rays, ideal for outdoor use. TPU/TPE (Flexible) : Rubber-like materials, elastic and abrasion-resistant, used for sheaths, gaskets, or flexible parts. Nylon (Polyamide) : Offers high mechanical strength, flexibility, and withstands high temperatures. Widely used for gears. Composite Filaments (with fibre/filler) : Base filaments (PLA, PETG, Nylon) filled with carbon, glass, or metal fibres, significantly improving stiffness, mechanical strength, and durability. HIPS/PVA (Support) : Used as support material, HIPS dissolves in limonene and PVA in water. 1.2 Expected profile of microplastics recovered from the Mediterranean Sea The specific polymers recovered from the ocean depend on the filtration depth and geographic location of the shipping route. The Active Marine Microplastic Remediation System (AMMRS) proposed by María Yoldi (yoldi 2025) is based on passive filtration technology integrated into the logistics of commercial shipping vessels. The core of the system is a filtration and recovery wheel designed to operate alongside the vessel hull, leveraging the vessel's movement to process vast volumes of water without requiring dedicated propulsion or significantly impacting the ship's operation or aerodynamics. The nets feature a pore size of 1 µm, which can capture even the smallest defined microplastic particles. As the AMMRS is placed in the laterals of the vessel (dual system), the target is to recover microplastics from surface or near-surface waters (floating polymers). Moreover, as the test were developed in the Mediterranean Sea, the recovered material is a complex mixture of synthetic polymers that include: 1. Dominant floating polymers (70–80%) The majority (70–80%) of recovered mass are low-density polyolefins: Polyethylene (PE) : The most abundant polymer found in marine surface waters. It originates from plastic bags, food packaging, and detergent bottles. Polypropylene (PP) : Frequently recovered alongside PE; it is a major component of bottle caps, ropes, and automotive parts. 2. Synthetic microfibers (15–20%) A significant portion (15–20%) are fibre-shaped particles: Polyester (PES) / Polyethylene Terephthalate (PET) : These are the most prevalent synthetic fibres in the ocean, originating from textile washing and discarded beverage bottles. Polyamide (Nylon) : Commonly recovered from degraded fishing nets and lines, as well as synthetic clothing. 3. Other common technical polymers (< 5%) As the design and operating parameters of the AMMRS were optimized to maximize recovery efficiency while minimizing drag, other microplastic recovered are: Polystyrene (PS) : Found as fragments or beads (expanded PS), often from food containers and packaging insulation. Polyvinyl Chloride (PVC) : A denser polymer frequently found in maritime environments due to its use in pipes and rigid packaging. Polyurethane (PUR) : Often present as fragments from sponges, coatings, or boat insulation. Acrylonitrile Butadiene Styrene (ABS) : Recovered as hard fragments, typically originating from consumer electronics and automotive components. 4. Marine-specific microplastics (< 5%) Alkyd resins / paint particles : Often identified as “ship painting” fragments, these are shed directly from the hulls of commercial vessels. Rubber fragments : Specifically, from tires, which enter the ocean through land-based runoff but are pervasive in marine environments. Table 1 shows the recovery profile of the raw material: Table 1 Recovery profile Polymer type Primary sources Relative abundance PE & PP packaging, bags, caps high (main mass) PET / Polyester bottles, textiles, nets very high (fibres) PS foam, food containers moderate PVC & PUR construction, coatings moderate Nylon fishing gear, textiles moderate 2 Raw material characterization 2.1 Complete characterization A multi-step analytical protocol focusing on physical morphology, chemical composition, and mass quantification has been developed to characterize the complex mix of marine plastics recovered by the Active Marine Microplastic Remediation System (AMMRS) . The standard scientific approach for mixed marine plastics involves the tests that are summarized in Table 2: Table 2 . Checklist for characterization Test Type Target information Best for FTIR Polymer chemical structure Mixed fragments >20 μm Raman High-resolution identification Fibers and sub-10 μm particles Py GC MS DSC Total mass concentration Quantifying recovery efficiency SEM-EDS Surface morphology & additives Studying degradation & toxicity As it is shown in table 2, the complete characterization of the recovered MPs involves the main points: 1. Physical characterization · Stereomicroscopy: The first step is to categorize the recovered material by shape (fragments, fibres, beads, films) and colour. This provides immediate data on the probable sources (e.g., fibres from textiles, fragments from degraded containers). · Scanning Electron Microscopy (SEM): SEM is used to examine the surface texture and degradation level. When coupled with EDS (Energy-dispersive X-ray spectroscopy) , it allows to identify inorganic additives or heavy metals adsorbed onto the plastic surface. 2. Chemical identification (polymer type) · Fourier Transform Infrared (FTIR) spectroscopy: is the most reliable standard for identifying the specific polymer (PE, PP, PET, etc.). (palmieri et al 2025) o ATR-FTIR for particles >500 μm. o Micro FTIR for particles <300 μm · Micro Raman Spectroscopy: Use this for very small particles (<1 μm) or for samples with high pigment interference that might obscure FTIR results. 3. Quantification and mass analysis · Pyrolysis-GC/MS (Gas Chromatography-Mass Spectrometry): Unlike spectroscopy which counts individual particles, this test determines the total mass (e.g., mg of PE per litre) of the polymers in your mix. It is essential for reporting the efficiency of the AMMRS in terms of weight recovered. · Differential Scanning Calorimetry (DSC): identify polymers based on their melting points. It is particularly useful for distinguishing between different grades of polyolefins (like LDPE vs. HDPE) in the recovered mix. 2.2 FTIR Fourier transform infrared spectroscopy (FTIR) is a fundamental analytical technique for the identification and characterization of polymeric materials. It is based on the absorption of infrared radiation by polymer molecules, generating a unique molecular "fingerprint" based on their chemical vibrations. According to Shimadzu, FTIR spectrometers support the identification of microplastics (Shimadzu 2022): · Material identification: Allows differentiation between different types of plastics (such as PE, PVC, or PET) by comparing their spectra with databases. · Quality control: Verifies the purity of raw materials and detects the presence of contaminants or impurities. · Quantitative analysis: Used to determine the quantity of additives, fillers, or percentages in polymer blends. · Degradation detection: Helps evaluate chemical changes caused by exposure to heat, UV light, or chemical agents. FTIR spectroscopy is categorized by its sampling techniques and spectral ranges, with the primary methods being Attenuated Total Reflectance (ATR) , transmission FTIR , diffuse reflectance (DRIFTS), specular reflectance, micro FTIR and nano FTIR. ATR is the most common, ideal for liquids and solids, while transmission is used for thinner samples. All these methods cover Mid-IR (MIR) , from 4000 to 400 cm -1 (2,5 to 25 mm), the standard region for chemical identification (functional groups); Near-IR (NIR) from 12500 to 4000 cm -1 (0,8 to 25 mm), used for quick, non-destructive, high-throughput analysis; and Far-IR (FIR) , from 400 to 10 cm -1 (25 to 1000 mm), used for inorganic/metal-organic compounds. From all these techniques, in these experiments with MPs recovered from the Mediterranean Sea we have tested: · ATR: This is the most common method by 2026 because it requires minimal sample preparation; it allows for the direct analysis of solids, films, or powders. · Transmission: Used for very thin samples or those prepared in KBr pellets. · Combined techniques (TGA-FTIR): Allows analysis of the gases released during the thermal decomposition of a polymer. The area below 1500 cm⁻¹ ( fingerprint region ) is crucial for identifying polymers with similar structures, as it contains absorption patterns unique to each material. (1) Relevant technical differentiation between LDPE and HDPE: Although both are polyethylene, FTIR spectroscopy allows differentiation by analysing subtle variations in the degree of branching across the flexural bands. (2) Difference between PET and PETG: PETG shows a distinctive band near 1015 cm⁻¹ and slight variation in the 1450 cm⁻¹ region due to the additional methylene groups from the glycol modifier. (3) PLA: It is easily identifiable by its very sharp carbonyl (C=O) peak shifted towards 1750 cm⁻¹, which distinguishes it from other polyesters. (4) TPU and PUR: Although both share urethane chemistry, TPU typically exhibits more defined bands of rigid and flexible segments, while PUR (foams) usually shows a free isocyanate band (~2275 cm⁻¹) if it has not fully cured. (5) PTFE (Teflon) is identifiable by the complete absence of C-H bands (around 2900 cm⁻¹), exhibiting only strong C-F stretch bands in the low-frequency region. Table 3 shows the key signals in the IR spectrum for the polymers: Table 3 . FTIR bands of the main polymers Polymer Key bands (cm -1 ) Chemical meaning Polyethylene (PE) (1) 2915, 2848, 1470, 718 C-H (CH 2 ) bond stretching and bending Polypropylene (PP) 2950, 1450, 1376 Presence of methyl (CH 3 ) groups absent in PE Polystyrene (PS) >3000, 1601, 1493, 700 Aromatic C-H stretching and ring vibrations. Polyvinyl Chloride (PVC) 1250, 615, 690 C-H bonds close to chlorine and C-Cl stretching Polyethylene Terephthalate (PET) (2) 1715, 1240, 1100 Very intense carbonyl (C=O) group and ester (C-O) bonds Polyamides (Nylon) ~3300 1640, 1540 N-H (amide A) C=O (amide I) bonds PTFE (Teflon) 1210, 1150 1240 640-540 2364 1800-1700 Strong CF 2 asymmetric and symmetric stretching C–C stretching vibration CF 2 wagging, bending, rocking CF 2 backbone modes. oxidation/double bonds (e.g., 1792 cm -1 CF=CF 2 ) PLA (Polylactic Acid) (3) 1750, 1180, 1085 Intense C=O (ester), C-O stretch and CH 3 bending. TPU (Thermoplastic Polyurethane) (4) 3330 1730-1700 1530 N-H (urethane) C=O (carbonyl) N-H bending (Amide II). PUR (Polyurethane) (4) 2275 1720, 1535 Presence of residual isocyanate (2275) urethane linkages Polyethylene Terephthalate Glycolate (PETG) (2) 1715, 1240, 1015 Like PET, but with cyclohexanedimethanol (CHDM) bands. 3 Recycling methodology The process of transforming microplastics (MPs) recovered from the Mediterranean Sea into functional 3D printing filament follows a multi-stage mechanical recycling workflow. Figure 1 shows the p rocess to recycle the MPs recovered from the ocean to make a recycled 3D printer filament: densifying, separation, crushing, mixing and homogenization and extrusion This methodology was executed in collaboration with the Alser company, utilizing their specialized industrial facilities for polymer processing: 3.1 Densifying (pre-processing) The initial stage focuses on the stabilization of the raw material recovered by the Active Marine Microplastic Remediation System (AMMRS). Because the material is recovered from marine environments, this step includes heating to remove residual moisture and sea salt, which can interfere with polymer properties. This initial densifying ensures the material is dry and compact enough for primary handling. 3.2 Separation The recovered material is a complex mixture of synthetic polymers, including PE, PP, PET, PS, PVC, and Nylon. Using Alser’s facilities, the material is separated by polymer type and physical morphology (fragments, fibres, beads, and films). Separation is guided by the recovery profile, which shows a high abundance of PE and PP (70–80%) and PET/Polyester fibres (15–20%). 3.3 Crushing Once separated, the microplastics undergo mechanical crushing to achieve a uniform particle size. This stage is critical for converting irregular marine debris, such as degraded fishing nets or bottle fragments, into a granular feedstock suitable for further processing. 3.4 Densifying (secondary) Following crushing, a second densifying stage is performed to increase the bulk density of the granules. This transforms the lightweight, crushed fragments into a more concentrated form that can be fed consistently into the extrusion machinery without causing air pockets or feed fluctuations. 3.5 Mixing and homogenizing The Mediterranean MPs are blended to create a consistent material profile. This is particularly important for polymer blends, where different grades of polyolefins (like LDPE and HDPE) or various additives and fillers must be evenly distributed to ensure the final filament has predictable thermal and mechanical properties. 3.6 Extrusion The homogenized material is processed through an industrial extruder to produce the recycled 3D printer thread. During this stage, parameters are carefully monitored to account for the unique characteristics of marine plastics, such as the potential presence of residual isocyanates in PUR or specific bands in PETG. The result is a continuous filament of standardized diameter. 3.7 3D Printer The final recycled filament is validated using a FLASHFORGE Adventurer 5M 3D printer. The technical parameters for testing are as follows: • Number of extruders : 1 • Nozzle Configuration : 0.4 mm default nozzle, with options for 0.6 mm for reinforced materials like PLA-CF or PETG-CF. • Thermal Settings : A maximum extruder temperature of 280°C and a rapid heating capability (200ºC in 35 seconds). • Operating temperature : 15–30ºC • Printing Speed : Standard printing is conducted at 300 mm/s, with a maximum capability of 600 mm/s. • Precision : The system maintains a printing accuracy of ± 0.2 mm and layer thicknesses between 0.1–0.4 mm. • Printing accuracy : ±0.2 mm (100 mm cube test) • Positioning accuracy : X/Y axis: 0.0125 mm; Z axis: 0.0025 mm • Layer thickness : 0.1–0.4 mm • Build size : 220x220x220 mm • Power supply : Input: AC 200-240V, 50Hz, 350W 4 Results The Spectral Database for Organic Compounds (SDBS) of the National Institute of Advanced Industrial Science and Technology (AIST) and were used to compare unknown spectra with established standards (aist 2025). Integrating these standards with machine learning models will allow for the prediction of even thermal properties such as the glass transition temperature directly from the spectrum. As explained previously, FTIR spectroscopy allows polymers to be identified through their characteristic absorption peaks, which act as a molecular “fingerprint”. The main peaks for each polymer present in the raw material recovered from the Mediterranean Sea are: Addition polymers (carbon backbone) • PE (Polyethylene) : Characterized by a simple hydrocarbon structure. o 2914 and 2847 cm⁻¹: C-H stretching (strong) o 1472 and 1462 cm⁻¹: Bending of CH 2 . o 718–720 cm⁻¹: Rocking of CH 2 chain (very characteristic for identifying PE). • PP (Polypropylene) : Like PE but with methyl groups (-CH 3 ) o 1375–1377 cm⁻¹: Bending of -CH 3 ; This is the key marker that distinguishes it from PE. o 2900–2950 cm⁻¹: C-H stretching. o 1165–1045 cm⁻¹: C-C skeleton vibrations. • PS (Polystyrene) : Shows signs of aromatic rings. o 3000–3100 cm⁻¹: Aromatic C-H stretching. o 1600, 1490, and 1447 cm⁻¹: C = C stretching of the benzene ring. o 698 cm⁻¹: Out-of-plane strain of the aromatic ring (strong diagnostic peak). • PVC (Polyvinyl chloride) : o 610–690 cm⁻¹: C-Cl stretching (the most diagnostic feature). o 1425–1430 cm⁻¹: Bending of CH₂ near the chlorine atom. Condensation Polymers (Contain Heteroatoms) • PET / Polyester : o 1715–1730 cm⁻¹: Very strong C = O (carbonyl) stretch. o 1240–1260 cm⁻¹: C-O stretch of the ester group. o 793 cm⁻¹: Specific signal used to identify PET in microplastic mixtures. • Nylon (Polyamide) : o 3295–3300 cm⁻¹: N-H stretch (Amide A). o 1635–1640 cm⁻¹: Amide I (C = O stretch). o 1540 cm⁻¹: Amide II (N-H bending and C-N stretch). • PUR (Polyurethane) : o 3300 cm⁻¹: N-H stretch (like nylon). o 1700–1730 cm⁻¹: Stretch C = O of the urethane group. 1 o 530 cm⁻¹: N-H bending vibration of the urethane structure. Table 4 summarizes the main bands of the recovered marine plastics: Table 4 Quick identification summary Polymer Key bands (cm − 1 ) Functional group PE 720 Rocking de CH 2 PP 1377 Metyl (CH 3 ) PS 698 Aromatic ring PVC 615 C-Cl bond PET 1720 / 793 Carbonyl Nylon 3300 / 1640 N-H bond / Amida I PUR 1710 Urethane (C = O) 4.1 Material abundance and economic suitability The dominant profile of PE and PP (70 to 80%) in the recovered Mediterranean samples presents a strategic advantage for scalable recycling. Although PLA and PETG are preferred for decorative and high-precision 3D printing, PE and PP are ubiquitous “commodity plastics” with lower synthesis costs. The AMMRS enabled recovery and subsequent mechanical processing offer a significantly more economic lifecycle compared to the production of virgin filaments. This economic feasibility is essential for the “Zero Plastic” objective, ensuring that the cost of remediation can be offset by the value of the recycled 3D printer thread 4.2 Functional validation of recycled filament: The challenge of printing with PE and PP, which are prone to warping due to high crystallinity, was addressed through the homogenization of the recovered mix and optimized thermal settings on the Flashforge Adventurer 5M. Figure 2 shows the items we have printed with the Flashforge Adventurer 5M 3D printer using the microplastics recovered from the Mediterranean Sea by the AMMRS system, and recycled following the multistep protocol defined in this article: The successful fabrication of the items shown in Fig. 2 (pin, keyring, necklace, and pendant) serves as a physical validation of the recycled filament. Despite the complex origin and potential degradation of marine-aged polymers, the resulting thread maintained a consistent flow through the 0.4 mm nozzle of the Flashforge Adventurer 5M. The printed objects exhibited high layer adhesion and structural integrity at an operating speed of 300 mm/s, demonstrating that the mechanical properties of the marine PE/PP blend are sufficient for producing consumer-grade goods without the need for virgin additives. The variety of functional items produced, ranging from industrial fasteners (pins) to aesthetic accessories, highlights the versatility of marine-recycled feedstock. By transforming “low-value” marine pollutants into “high-value” customizable goods, the AMMRS framework provides a tangible economic incentive for maritime stakeholders to adopt remediation technologies. The successful printing of fine details indicates that the homogenized marine PE/PP blend can compete with standard filaments in non-structural applications, directly supporting the “Zero Plastic” objective. 5 Discussion The characterization of Mediterranean microplastics recovered via the AMMRS confirms the significant abundance of polyolefins (PE and PP), which align with global trends of marine debris. While the 3D printing industry traditionally prioritizes technical polymers like PLA, PETG, and ABS for their ease of use and thermal stability, the sheer volume of PE and PP in the marine environment makes them the most pragmatic candidates for a circular economy. Our results demonstrate that the degradation typically observed in marine-aged plastics, identified through specific FTIR bands such as the carbonyl peaks near 1715 cm⁻¹, did not preclude their mechanical recyclability. The economic viability of this process is a key finding. Traditional recycling often suffers from high logistical costs associated with dedicated recovery missions. By utilizing the AMMRS as a passive system on commercial vessels, the marginal cost of recovery is minimized. Furthermore, the mechanical recycling path (densifying and crushing) is significantly more energy-efficient than chemical upcycling. The challenge of printing with PE and PP, which are prone to warping due to high crystallinity, was addressed through the homogenization of the recovered mix and optimized thermal settings on the Flashforge Adventurer 5M. By proving that these "low-value" marine pollutants can be successfully converted into 3D printing feedstock, this study provides an incentive for the maritime industry to adopt remediation technologies. Future work should explore the inclusion of carbon fibre or fiberglass reinforcements (PETG-CF/PLA-CF) to enhance the structural rigidity of the marine-recycled filament, further bridging the gap between recycled materials and high-performance industrial standards. The variety of items produced, ranging from industrial pins to aesthetic jewellery elements, highlights the versatility of marine-recycled feedstock. By transforming 'low-value' marine pollutants into “high-value” customizable goods, the AMMRS framework provides a tangible incentive for maritime stakeholders. The successful printing of fine details (as seen in the “María” nameplate and pendant geometries) indicates that the homogenized marine PE/PP blend can compete with standard PLA in non-structural applications, further supporting the economic feasibility of the “Zero Plastic” objective 6 Conclusions and future perspectives Table 5 shows why PE/PP are the pragmatic choice for marine recycling compared to the standard virgin polymers used as 3D printer filaments. Table 5 Comparison between most used 3D printing filaments and recycled microplastics Material Primary use in 3D printing Recovery abundance (AMMRS) Recovery/Recycling complexity PLA Most popular/Easy Rare in marine surface N/A (Virgin source) PETG Durable/Versatile Moderate (as PET fibres) High (requires high temperature) PE / PP Industrial/Functional 70–80% (Dominant) Low / Economic By proving that these “low-value” marine pollutants can be successfully converted into 3D printing feedstock, this study provides a blueprint for turning ocean waste into industrial feedstock. The production of functional prototypes using standard FDM technology validates the entire workflow, from AMMRS recovery to the final object, proving that marine microplastics can be effectively reintegrated into the industrial value chain. Declarations Acknowledgements We thank the company Alser for allowing us to use their separation, crushing, densifying, mixing/homogenizing, extrusion, compositing facilities to process the raw material and help us define the appropriate parameters for recycling microplastics recovered from the ocean. Funding This work was supported by the B0036-2526/711 project: “Reduce, recover, reuse and recycle microplastics from the ocean (zero plastic)”, one of the Pre-competitive Research Projects 2025 approved by the Universidad Internacional de La Rioja. The corresponding author Dr. María Yoldi is the Principal Researcher of this project, and all the author collaborates in the B0036-2526/711 project. Authors’ Contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Dr. María Yoldi Sangüesa. The first draft of the manuscript was written by Dr. María Yoldi Sangüesa and Dr. Lucía Grijalvo and Dr. Silvia Jiménez commented on previous versions of the manuscript. All authors read and approved the final manuscript. We have not submitted this manuscript to a preprint server before submitting it to Scientific Reports . Ethical Approval* This is not applicable Consent to Participate* This is not applicable Consent to Publish* This is not applicable Competing Interests All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. Data Availability Statement No data, text, or theories by others are presented as if they were the author’s own. Proper acknowledgements to other works must be, quotation marks are used for verbatim copying of material, and permissions secured for material that is copyrighted. The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. Clinical trial number This is not applicable References [aist 2025] National Institute of Advanced Industrial Science and Technology (AIST), Spectral Database for Organic Compounds (SDBS) & Available in: https://sdbs.db.aist.go.jp [fan, C. et al. Microplastic constituent identification from admixtures by Fourier-transform infrared (FTIR) spectroscopy: The use of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and nylon (NY) as the model constituents. Environmental Technology & Innovation Volume 23, 101798, Available in: (2025). https://doi.org/10.1016/j.eti.2021.101798 [palmieri, R. et al. Marine Microplastic Classification by Hyperspectral Imaging: Case Studies from the Mediterranean Sea, the Strait of Gibraltar, the Western Atlantic Ocean and the Bay of Biscay, Appl. Sci. 14(20), 9310; Available in: (2024). https://doi.org/10.3390/app14209310 [Shimadzu 2022] Shimadzi. Excellence in Science. Fourier Transform Infrared Spectrophotometers Support the Identification of Microplastics. Available in: (2022). https://www.shimadzu.com/today/20220517-1.html#anchor02 [Yoldi 2025] Yoldi, M. From reduction to recovery: integrating passive filtration systems in maritime logistics to close the plastic loop Scientific Reports. Available in: (2025). https://link.springer.com/journal/13762 [Yoldi, M. et al. iménez S., Reduce, recover, reuse, and recycle ocean microplastics: a comprehensive approach to marine and terrestrial sustainability Scientific Report. Available in: (2026). https://link.springer.com/journal/13762 Additional Declarations No competing interests reported. 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Sanguesa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYJCCAyCCjyGx8QEDgwQJWtgYEpsNoFoYG4jSx8aQwAazAr8W3fazDw/8YDgsx8ae3FbNu8Min0G6+fgDfFrMzqQbHOxhOGzMxvOw7TbvGQnLBpljiXhtMTuQxnCAh+FwYptEIlBLm4QBg0SOIX4t558xHPwD1VIM0ZL/Eb+WG2kMh2G2MENtwe99sxvPGA7LGKSD/NIsOReohU0izXAGfoelMX98U2Etx8+e/vDD27Y6A36J5Acf8GmBAINmBJuNsHIwqCNS3SgYBaNgFIxIAACynEX953b7tQAAAABJRU5ErkJggg==","orcid":"","institution":"Universidad Internacional De La Rioja","correspondingAuthor":true,"prefix":"","firstName":"María","middleName":"Yoldi","lastName":"Sanguesa","suffix":""},{"id":583665015,"identity":"575ed31d-6045-46aa-ab63-72c644695180","order_by":1,"name":"Lucía Grijalvo Fernández","email":"","orcid":"","institution":"Universidad Internacional De La Rioja","correspondingAuthor":false,"prefix":"","firstName":"Lucía","middleName":"Grijalvo","lastName":"Fernández","suffix":""},{"id":583665016,"identity":"08608c02-ba9e-470b-9e85-5321b3615fcd","order_by":2,"name":"Silvia Jiménez Herrera","email":"","orcid":"","institution":"Universidad Internacional De La Rioja","correspondingAuthor":false,"prefix":"","firstName":"Silvia","middleName":"Jiménez","lastName":"Herrera","suffix":""}],"badges":[],"createdAt":"2026-01-27 10:41:53","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8709326/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8709326/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101635790,"identity":"fd111e58-fefe-475f-8c7e-0661bdba0cd5","added_by":"auto","created_at":"2026-02-02 06:26:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":166559,"visible":true,"origin":"","legend":"\u003cp\u003eProcess to recycle the MPs recovered from the ocean\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8709326/v1/91dedf6689d908a7191c68ee.png"},{"id":101635769,"identity":"6f6bbb88-3fa0-4405-a75d-1b68c3f76194","added_by":"auto","created_at":"2026-02-02 06:26:39","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":336648,"visible":true,"origin":"","legend":"\u003cp\u003eItems printed with recycled marine microplastics\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8709326/v1/86fe5bbd0ab4bc454824fcba.jpeg"},{"id":102297989,"identity":"c0a0bdaa-2209-4f2d-9da9-aa4de17d002c","added_by":"auto","created_at":"2026-02-10 10:30:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2083239,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8709326/v1/9a48a384-bad1-4acd-8344-6bf19f7dc404.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003e3D Printer Thread Manufacturing From Microplastics Recovered From the Ocean\u003c/p\u003e","fulltext":[{"header":"Highlights","content":"\u003cp\u003eIntegration of \u003cstrong\u003eAMMRS passive filtration\u003c/strong\u003e into commercial shipping logistics for efficient MP recovery.\u003c/p\u003e\n\u003cp\u003eCharacterization of recovered Mediterranean MPs reveals a dominant profile of \u003cstrong\u003ePE and PP (70-80%).\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSuccessful conversion of mixed marine microplastics into \u003cstrong\u003e3D printer thread\u003c/strong\u003e through a multi-stage mechanical recycling process.\u003c/p\u003e\n\u003cp\u003eValidation of polymer purity and degradation levels using \u003cstrong\u003eATR-FTIR\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;DSC\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eDemonstration of \u003cstrong\u003ePE and PP\u003c/strong\u003e, which constitute 70-80% of \u003cstrong\u003erecovered marine microplastics\u003c/strong\u003e, as an \u003cstrong\u003eeconomic and viable alternative to virgin PLA/PETG\u0026nbsp;\u003c/strong\u003efilaments.\u003c/p\u003e\n\u003cp\u003eValidation of the recycling workflow through the \u003cstrong\u003esuccessful 3D printing of functional prototypes\u003c/strong\u003e (pins, keyrings, and jewellery) using the recovered marine feedstock.\u003c/p\u003e"},{"header":"1 Introduction","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003e1.1 3D printing filaments\u003c/h2\u003e \u003cp\u003eThe most used 3D printing filaments are PLA (easy to use, decorative), PETG (durable, versatile), ABS/ASA (strong, functional), and TPU (flexible). Technical materials such as nylon, polycarbonate, and composites with carbon fibre or fiberglass are also noteworthy for increased rigidity and industrial applications. The choice depends on whether ease of printing (PLA), mechanical strength (ABS/Nylon), or flexibility (TPU) is required. Based on these ideas, the key points of any of them are:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePLA (Polylactic Acid)\u003c/b\u003e: The most popular and easiest to use, ideal for prototypes, models, and educational purposes. It typically does not require a heated bed.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePETG (Polyethylene Terephthalate Glycolyzed)\u003c/b\u003e: Excellent balance, mechanically and chemically resistant, more durable than PLA, and easy to print.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eABS (Acrylonitrile Butadiene Styrene)\u003c/b\u003e: Very resistant to impacts and high temperatures. Common in automotive and electronics, but complex to print due to warping.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eASA (Acrylonitrile Styrene Acrylate)\u003c/b\u003e: Like ABS but with greater resistance to weathering and UV rays, ideal for outdoor use.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eTPU/TPE (Flexible)\u003c/b\u003e: Rubber-like materials, elastic and abrasion-resistant, used for sheaths, gaskets, or flexible parts.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eNylon (Polyamide)\u003c/b\u003e: Offers high mechanical strength, flexibility, and withstands high temperatures. Widely used for gears.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eComposite Filaments (with fibre/filler)\u003c/b\u003e: Base filaments (PLA, PETG, Nylon) filled with carbon, glass, or metal fibres, significantly improving stiffness, mechanical strength, and durability.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eHIPS/PVA (Support)\u003c/b\u003e: Used as support material, HIPS dissolves in limonene and PVA in water.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1.2 Expected profile of microplastics recovered from the Mediterranean Sea\u003c/h2\u003e \u003cp\u003eThe specific polymers recovered from the ocean depend on the filtration depth and geographic location of the shipping route. The \u003cem\u003eActive Marine Microplastic Remediation System (AMMRS)\u003c/em\u003e proposed by Mar\u0026iacute;a Yoldi (yoldi 2025) is based on passive filtration technology integrated into the logistics of commercial shipping vessels. The core of the system is a filtration and recovery wheel designed to operate alongside the vessel hull, leveraging the vessel's movement to process vast volumes of water without requiring dedicated propulsion or significantly impacting the ship's operation or aerodynamics. The nets feature a pore size of 1 \u0026micro;m, which can capture even the smallest defined microplastic particles. As the AMMRS is placed in the laterals of the vessel (dual system), the target is to recover microplastics from surface or near-surface waters (floating polymers). Moreover, as the test were developed in the Mediterranean Sea, the recovered material is a complex mixture of synthetic polymers that include:\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003e1. Dominant floating polymers (70–80%)\u003c/h3\u003e\n\u003cp\u003eThe majority (70\u0026ndash;80%) of recovered mass are low-density polyolefins:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolyethylene (PE)\u003c/b\u003e: The most abundant polymer found in marine surface waters. It originates from plastic bags, food packaging, and detergent bottles.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolypropylene (PP)\u003c/b\u003e: Frequently recovered alongside PE; it is a major component of bottle caps, ropes, and automotive parts.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e\n\u003ch3\u003e2. Synthetic microfibers (15–20%)\u003c/h3\u003e\n\u003cp\u003eA significant portion (15\u0026ndash;20%) are fibre-shaped particles:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolyester (PES) / Polyethylene Terephthalate (PET)\u003c/b\u003e: These are the most prevalent synthetic fibres in the ocean, originating from textile washing and discarded beverage bottles.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolyamide (Nylon)\u003c/b\u003e: Commonly recovered from degraded fishing nets and lines, as well as synthetic clothing.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e\n\u003ch3\u003e3. Other common technical polymers (\u003c 5%)\u003c/h3\u003e\n\u003cp\u003eAs the design and operating parameters of the AMMRS were optimized to maximize recovery efficiency while minimizing drag, other microplastic recovered are:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolystyrene (PS)\u003c/b\u003e: Found as fragments or beads (expanded PS), often from food containers and packaging insulation.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolyvinyl Chloride (PVC)\u003c/b\u003e: A denser polymer frequently found in maritime environments due to its use in pipes and rigid packaging.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003ePolyurethane (PUR)\u003c/b\u003e: Often present as fragments from sponges, coatings, or boat insulation.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eAcrylonitrile Butadiene Styrene (ABS)\u003c/b\u003e: Recovered as hard fragments, typically originating from consumer electronics and automotive components.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003e4. Marine-specific microplastics (\u0026lt;\u0026thinsp;5%)\u003c/b\u003e \u003c/p\u003e\u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eAlkyd resins / paint particles\u003c/b\u003e: Often identified as \u0026ldquo;ship painting\u0026rdquo; fragments, these are shed directly from the hulls of commercial vessels.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eRubber fragments\u003c/b\u003e: Specifically, from tires, which enter the ocean through land-based runoff but are pervasive in marine environments.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the recovery profile of the raw material:\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eRecovery profile\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolymer type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrimary sources\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRelative abundance\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePE \u0026amp; PP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003epackaging, bags, caps\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ehigh (main mass)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePET / Polyester\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ebottles, textiles, nets\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003every high (fibres)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efoam, food containers\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003emoderate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePVC \u0026amp; PUR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003econstruction, coatings\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003emoderate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNylon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003efishing gear, textiles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003emoderate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"2 Raw material characterization","content":"\u003ch2\u003e2.1\u0026nbsp; \u0026nbsp;\u0026nbsp;Complete characterization\u003c/h2\u003e\n\u003cp\u003eA multi-step analytical protocol focusing on physical morphology, chemical composition, and mass quantification has been developed to characterize the complex mix of marine plastics recovered by the \u003cem\u003eActive Marine Microplastic Remediation System (AMMRS)\u003c/em\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe standard scientific approach for mixed marine plastics involves the tests that are summarized in Table 2:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003cstrong\u003e.\u003c/strong\u003e Checklist for characterization\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"652\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTest Type\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTarget information\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBest for\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFTIR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePolymer chemical structure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMixed fragments \u0026gt;20 \u0026mu;m\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eRaman\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHigh-resolution identification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFibers and sub-10 \u0026mu;m particles\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePy\u003c/p\u003e\n \u003cp\u003eGC\u003c/p\u003e\n \u003cp\u003eMS\u003c/p\u003e\n \u003cp\u003eDSC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTotal mass concentration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eQuantifying recovery efficiency\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSEM-EDS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSurface morphology \u0026amp; additives\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eStudying degradation \u0026amp; toxicity\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAs it is shown in table 2, the complete characterization of the recovered MPs involves the main points:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.\u0026nbsp;\u0026nbsp;Physical characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eStereomicroscopy:\u003c/strong\u003e The first step is to categorize the recovered material by shape (fragments, fibres, beads, films) and colour. This provides immediate data on the probable sources (e.g., fibres from textiles, fragments from degraded containers).\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eScanning Electron Microscopy (SEM):\u003c/strong\u003e SEM is used to examine the surface texture and degradation level. When coupled with \u003cstrong\u003eEDS (Energy-dispersive X-ray spectroscopy)\u003c/strong\u003e, it allows to identify inorganic additives or heavy metals adsorbed onto the plastic surface.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.\u0026nbsp;\u0026nbsp;Chemical identification (polymer type)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eFourier Transform Infrared (FTIR) spectroscopy:\u003c/strong\u003e is the most reliable standard for identifying the specific polymer (PE, PP, PET, etc.). (palmieri et al 2025)\u003c/p\u003e\n\u003cp\u003eo ATR-FTIR for particles \u0026gt;500 \u0026mu;m.\u003c/p\u003e\n\u003cp\u003eo Micro FTIR for particles \u0026lt;300 \u0026mu;m\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eMicro Raman Spectroscopy:\u003c/strong\u003e Use this for very small particles (\u0026lt;1 \u0026mu;m) or for samples with high pigment interference that might obscure FTIR results.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.\u0026nbsp;\u0026nbsp;Quantification and mass analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003ePyrolysis-GC/MS (Gas Chromatography-Mass Spectrometry):\u003c/strong\u003e Unlike spectroscopy which counts individual particles, this test determines the total mass (e.g., mg of PE per litre) of the polymers in your mix. It is essential for reporting the efficiency of the \u003cem\u003eAMMRS\u003c/em\u003e in terms of weight recovered.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eDifferential Scanning Calorimetry (DSC):\u003c/strong\u003e identify polymers based on their melting points. It is particularly useful for distinguishing between different grades of polyolefins (like LDPE vs. HDPE) in the recovered mix.\u003c/p\u003e\n\u003ch2\u003e2.2\u0026nbsp; \u0026nbsp;\u0026nbsp;FTIR\u003c/h2\u003e\n\u003cp\u003eFourier transform infrared spectroscopy (FTIR) is a fundamental analytical technique for the identification and characterization of polymeric materials. It is based on the absorption of infrared radiation by polymer molecules, generating a unique molecular \u0026quot;fingerprint\u0026quot; based on their chemical vibrations. According to Shimadzu, FTIR spectrometers support the identification of microplastics (Shimadzu 2022):\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eMaterial identification:\u003c/strong\u003e Allows differentiation between different types of plastics (such as PE, PVC, or PET) by comparing their spectra with databases.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eQuality control:\u003c/strong\u003e Verifies the purity of raw materials and detects the presence of contaminants or impurities.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eQuantitative analysis:\u003c/strong\u003e Used to determine the quantity of additives, fillers, or percentages in polymer blends.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eDegradation detection:\u003c/strong\u003e Helps evaluate chemical changes caused by exposure to heat, UV light, or chemical agents.\u003c/p\u003e\n\u003cp\u003eFTIR spectroscopy is categorized by its sampling techniques and spectral ranges, with the primary methods being \u003cstrong\u003eAttenuated Total Reflectance (ATR)\u003c/strong\u003e, \u003cstrong\u003etransmission FTIR\u003c/strong\u003e, \u003cstrong\u003ediffuse reflectance (DRIFTS), specular reflectance, micro FTIR\u0026nbsp;\u003c/strong\u003eand\u003cstrong\u003e\u0026nbsp;nano FTIR.\u0026nbsp;\u003c/strong\u003eATR is the most common, ideal for liquids and solids, while transmission is used for thinner samples.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll these methods cover \u003cstrong\u003eMid-IR (MIR)\u003c/strong\u003e, from\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e4000 to 400 cm\u003csup\u003e-1\u003c/sup\u003e (2,5 to 25\u0026nbsp;mm), the standard region for chemical identification (functional groups); \u003cstrong\u003eNear-IR (NIR)\u003c/strong\u003e from\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e12500 to 4000 cm\u003csup\u003e-1\u003c/sup\u003e (0,8 to 25\u0026nbsp;mm), used for quick, non-destructive, high-throughput analysis; and \u003cstrong\u003eFar-IR (FIR)\u003c/strong\u003e, from\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e400 to 10 cm\u003csup\u003e-1\u003c/sup\u003e (25 to 1000\u0026nbsp;mm), \u0026nbsp;used for inorganic/metal-organic compounds.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFrom all these techniques, in these experiments with MPs recovered from the Mediterranean Sea we have tested:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eATR:\u003c/strong\u003e This is the most common method by 2026 because it requires minimal sample preparation; it allows for the direct analysis of solids, films, or powders.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eTransmission:\u003c/strong\u003e Used for very thin samples or those prepared in KBr pellets.\u003c/p\u003e\n\u003cp\u003e\u0026middot; \u003cstrong\u003eCombined techniques (TGA-FTIR):\u003c/strong\u003e Allows analysis of the gases released during the thermal decomposition of a polymer.\u003c/p\u003e\n\u003cp\u003eThe area below 1500 cm⁻\u0026sup1; (\u003cem\u003efingerprint region\u003c/em\u003e) is crucial for identifying polymers with similar structures, as it contains absorption patterns unique to each material.\u003c/p\u003e\n\u003cp\u003e(1) \u003cstrong\u003eRelevant technical differentiation between LDPE and HDPE:\u003c/strong\u003e Although both are polyethylene, FTIR spectroscopy allows differentiation by analysing subtle variations in the degree of branching across the flexural bands.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(2) \u003cstrong\u003eDifference between PET and PETG:\u003c/strong\u003e PETG shows a distinctive band near 1015 cm⁻\u0026sup1; and slight variation in the 1450 cm⁻\u0026sup1; region due to the additional methylene groups from the glycol modifier.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e(3) \u003cstrong\u003ePLA:\u003c/strong\u003e It is easily identifiable by its very sharp carbonyl (C=O) peak shifted towards 1750 cm⁻\u0026sup1;, which distinguishes it from other polyesters.\u003c/p\u003e\n\u003cp\u003e(4) \u003cstrong\u003eTPU and PUR:\u003c/strong\u003e Although both share urethane chemistry, TPU typically exhibits more defined bands of rigid and flexible segments, while PUR (foams) usually shows a free isocyanate band (~2275 cm⁻\u0026sup1;) if it has not fully cured.\u003c/p\u003e\n\u003cp\u003e(5) \u003cstrong\u003ePTFE (Teflon)\u003c/strong\u003e is identifiable by the complete absence of C-H bands (around 2900 cm⁻\u0026sup1;), exhibiting only strong C-F stretch bands in the low-frequency region.\u003c/p\u003e\n\u003cp\u003eTable 3 shows the key signals in the IR spectrum for the polymers:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003cstrong\u003e.\u003c/strong\u003e FTIR bands of the main polymers\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\" class=\"fr-table-selection-hover\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePolymer\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eKey bands (cm\u003csup\u003e-1\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eChemical meaning\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolyethylene (PE) (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2915, 2848, 1470, 718\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC-H (CH\u003csub\u003e2\u003c/sub\u003e) bond stretching and bending\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolypropylene (PP)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2950, 1450, 1376\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003ePresence of methyl (CH\u003csub\u003e3\u003c/sub\u003e) groups absent in PE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolystyrene (PS)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e\u0026gt;3000, 1601, 1493, 700\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eAromatic C-H stretching and ring vibrations.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolyvinyl Chloride (PVC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1250, 615, 690\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eC-H bonds close to chlorine and C-Cl stretching\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolyethylene Terephthalate (PET) (2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1715, 1240, 1100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eVery intense carbonyl (C=O) group and ester (C-O) bonds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolyamides (Nylon)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e~3300\u003c/p\u003e\n \u003cp\u003e1640, 1540\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eN-H (amide A)\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eC=O (amide I) bonds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePTFE (Teflon)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1210, 1150\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e1240\u003c/p\u003e\n \u003cp\u003e640-540\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e2364\u003c/p\u003e\n \u003cp\u003e1800-1700\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eStrong CF\u003csub\u003e2\u003c/sub\u003e asymmetric and symmetric stretching\u003c/p\u003e\n \u003cp\u003eC\u0026ndash;C stretching vibration\u003c/p\u003e\n \u003cp\u003eCF\u003csub\u003e2\u003c/sub\u003e wagging, bending, rocking\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eCF\u003csub\u003e2\u003c/sub\u003e backbone modes.\u003c/p\u003e\n \u003cp\u003eoxidation/double bonds (e.g., 1792 cm\u003csup\u003e-1\u003c/sup\u003e CF=CF\u003csub\u003e2\u003c/sub\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePLA (Polylactic Acid) (3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1750, 1180, 1085\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eIntense C=O (ester), C-O stretch and CH\u003csub\u003e3\u003c/sub\u003e bending.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eTPU (Thermoplastic Polyurethane) (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e3330\u003c/p\u003e\n \u003cp\u003e1730-1700\u003c/p\u003e\n \u003cp\u003e1530\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eN-H (urethane)\u003c/p\u003e\n \u003cp\u003eC=O (carbonyl)\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eN-H bending (Amide II).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePUR (Polyurethane) (4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e2275\u003c/p\u003e\n \u003cp\u003e1720, 1535\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003ePresence of residual isocyanate (2275)\u003c/p\u003e\n \u003cp\u003eurethane linkages\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003ePolyethylene Terephthalate Glycolate (PETG) (2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003e1715, 1240, 1015\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 34px;\"\u003e\n \u003cp\u003eLike PET, but with cyclohexanedimethanol (CHDM) bands.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"3 Recycling methodology","content":"\u003cp\u003eThe process of transforming microplastics (MPs) recovered from the Mediterranean Sea into functional 3D printing filament follows a multi-stage mechanical recycling workflow. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cem\u003eshows the p\u003c/em\u003erocess to recycle the MPs recovered from the ocean to make a recycled 3D printer filament: densifying, separation, crushing, mixing and homogenization and extrusion\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThis methodology was executed in collaboration with the Alser company, utilizing their specialized industrial facilities for polymer processing:\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Densifying (pre-processing)\u003c/h2\u003e \u003cp\u003eThe initial stage focuses on the stabilization of the raw material recovered by the \u003cem\u003eActive Marine Microplastic Remediation System (AMMRS).\u003c/em\u003e Because the material is recovered from marine environments, this step includes heating to remove residual moisture and sea salt, which can interfere with polymer properties. This initial densifying ensures the material is dry and compact enough for primary handling.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Separation\u003c/h2\u003e \u003cp\u003eThe recovered material is a complex mixture of synthetic polymers, including PE, PP, PET, PS, PVC, and Nylon. Using Alser\u0026rsquo;s facilities, the material is separated by polymer type and physical morphology (fragments, fibres, beads, and films). Separation is guided by the recovery profile, which shows a high abundance of PE and PP (70\u0026ndash;80%) and PET/Polyester fibres (15\u0026ndash;20%).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Crushing\u003c/h2\u003e \u003cp\u003eOnce separated, the microplastics undergo mechanical crushing to achieve a uniform particle size. This stage is critical for converting irregular marine debris, such as degraded fishing nets or bottle fragments, into a granular feedstock suitable for further processing.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Densifying (secondary)\u003c/h2\u003e \u003cp\u003eFollowing crushing, a second densifying stage is performed to increase the bulk density of the granules. This transforms the lightweight, crushed fragments into a more concentrated form that can be fed consistently into the extrusion machinery without causing air pockets or feed fluctuations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Mixing and homogenizing\u003c/h2\u003e \u003cp\u003eThe Mediterranean MPs are blended to create a consistent material profile. This is particularly important for polymer blends, where different grades of polyolefins (like LDPE and HDPE) or various additives and fillers must be evenly distributed to ensure the final filament has predictable thermal and mechanical properties.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Extrusion\u003c/h2\u003e \u003cp\u003eThe homogenized material is processed through an industrial extruder to produce the recycled 3D printer thread. During this stage, parameters are carefully monitored to account for the unique characteristics of marine plastics, such as the potential presence of residual isocyanates in PUR or specific bands in PETG. The result is a continuous filament of standardized diameter.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.7 3D Printer\u003c/h2\u003e \u003cp\u003eThe final recycled filament is validated using a FLASHFORGE Adventurer 5M 3D printer. The technical parameters for testing are as follows:\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eNumber of extruders\u003c/b\u003e: 1\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eNozzle Configuration\u003c/b\u003e: 0.4 mm default nozzle, with options for 0.6 mm for reinforced materials like PLA-CF or PETG-CF.\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eThermal Settings\u003c/b\u003e: A maximum extruder temperature of 280\u0026deg;C and a rapid heating capability (200\u0026ordm;C in 35 seconds).\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eOperating temperature\u003c/b\u003e: 15\u0026ndash;30\u0026ordm;C\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePrinting Speed\u003c/b\u003e: Standard printing is conducted at 300 mm/s, with a maximum capability of 600 mm/s.\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePrecision\u003c/b\u003e: The system maintains a printing accuracy of \u0026plusmn;\u0026thinsp;0.2 mm and layer thicknesses between 0.1\u0026ndash;0.4 mm.\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePrinting accuracy\u003c/b\u003e: \u0026plusmn;0.2 mm (100 mm cube test)\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePositioning accuracy\u003c/b\u003e: X/Y axis: 0.0125 mm; Z axis: 0.0025 mm\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eLayer thickness\u003c/b\u003e: 0.1\u0026ndash;0.4 mm\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eBuild size\u003c/b\u003e: 220x220x220 mm\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePower supply\u003c/b\u003e: Input: AC 200-240V, 50Hz, 350W\u003c/p\u003e \u003c/div\u003e"},{"header":"4 Results","content":"\u003cp\u003eThe Spectral Database for Organic Compounds (SDBS) of the National Institute of Advanced Industrial Science and Technology (AIST) and were used to compare unknown spectra with established standards (aist 2025). Integrating these standards with machine learning models will allow for the prediction of even thermal properties such as the glass transition temperature directly from the spectrum.\u003c/p\u003e \u003cp\u003eAs explained previously, FTIR spectroscopy allows polymers to be identified through their characteristic absorption peaks, which act as a molecular \u0026ldquo;fingerprint\u0026rdquo;. The main peaks for each polymer present in the raw material recovered from the Mediterranean Sea are:\u003c/p\u003e \u003cp\u003e \u003cb\u003eAddition polymers (carbon backbone)\u003c/b\u003e \u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePE (Polyethylene)\u003c/b\u003e: Characterized by a simple hydrocarbon structure.\u003c/p\u003e \u003cp\u003eo 2914 and 2847 cm⁻\u0026sup1;: C-H stretching (strong)\u003c/p\u003e \u003cp\u003eo 1472 and 1462 cm⁻\u0026sup1;: Bending of CH\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eo 718\u0026ndash;720 cm⁻\u0026sup1;: Rocking of CH\u003csub\u003e2\u003c/sub\u003e chain (very characteristic for identifying PE).\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePP (Polypropylene)\u003c/b\u003e: Like PE but with methyl groups (-CH\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e \u003cp\u003eo 1375\u0026ndash;1377 cm⁻\u0026sup1;: Bending of -CH\u003csub\u003e3\u003c/sub\u003e; This is the key marker that distinguishes it from PE.\u003c/p\u003e \u003cp\u003eo 2900\u0026ndash;2950 cm⁻\u0026sup1;: C-H stretching.\u003c/p\u003e \u003cp\u003eo 1165\u0026ndash;1045 cm⁻\u0026sup1;: C-C skeleton vibrations.\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePS (Polystyrene)\u003c/b\u003e: Shows signs of aromatic rings.\u003c/p\u003e \u003cp\u003eo 3000\u0026ndash;3100 cm⁻\u0026sup1;: Aromatic C-H stretching.\u003c/p\u003e \u003cp\u003eo 1600, 1490, and 1447 cm⁻\u0026sup1;: C\u0026thinsp;=\u0026thinsp;C stretching of the benzene ring.\u003c/p\u003e \u003cp\u003eo 698 cm⁻\u0026sup1;: Out-of-plane strain of the aromatic ring (strong diagnostic peak).\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePVC (Polyvinyl chloride)\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eo 610\u0026ndash;690 cm⁻\u0026sup1;: C-Cl stretching (the most diagnostic feature).\u003c/p\u003e \u003cp\u003eo 1425\u0026ndash;1430 cm⁻\u0026sup1;: Bending of CH₂ near the chlorine atom. Condensation Polymers (Contain Heteroatoms)\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePET / Polyester\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eo 1715\u0026ndash;1730 cm⁻\u0026sup1;: Very strong C\u0026thinsp;=\u0026thinsp;O (carbonyl) stretch.\u003c/p\u003e \u003cp\u003eo 1240\u0026ndash;1260 cm⁻\u0026sup1;: C-O stretch of the ester group.\u003c/p\u003e \u003cp\u003eo 793 cm⁻\u0026sup1;: Specific signal used to identify PET in microplastic mixtures.\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003eNylon (Polyamide)\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eo 3295\u0026ndash;3300 cm⁻\u0026sup1;: N-H stretch (Amide A).\u003c/p\u003e \u003cp\u003eo 1635\u0026ndash;1640 cm⁻\u0026sup1;: Amide I (C\u0026thinsp;=\u0026thinsp;O stretch).\u003c/p\u003e \u003cp\u003eo 1540 cm⁻\u0026sup1;: Amide II (N-H bending and C-N stretch).\u003c/p\u003e \u003cp\u003e\u0026bull; \u003cb\u003ePUR (Polyurethane)\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eo 3300 cm⁻\u0026sup1;: N-H stretch (like nylon).\u003c/p\u003e \u003cp\u003eo 1700\u0026ndash;1730 cm⁻\u0026sup1;: Stretch C\u0026thinsp;=\u0026thinsp;O of the urethane group. 1\u003c/p\u003e \u003cp\u003eo 530 cm⁻\u0026sup1;: N-H bending vibration of the urethane structure.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e summarizes the main bands of the recovered marine plastics:\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eQuick identification summary\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolymer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKey bands (cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFunctional group\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e720\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRocking de CH\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1377\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMetyl (CH\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e698\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAromatic ring\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePVC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e615\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC-Cl bond\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePET\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1720 / 793\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCarbonyl\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNylon\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3300 / 1640\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN-H bond / Amida I\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePUR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1710\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eUrethane (C\u0026thinsp;=\u0026thinsp;O)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Material abundance and economic suitability\u003c/h2\u003e \u003cp\u003eThe dominant profile of PE and PP (70 to 80%) in the recovered Mediterranean samples presents a strategic advantage for scalable recycling. Although PLA and PETG are preferred for decorative and high-precision 3D printing, PE and PP are ubiquitous \u0026ldquo;commodity plastics\u0026rdquo; with lower synthesis costs. The AMMRS enabled recovery and subsequent mechanical processing offer a significantly more economic lifecycle compared to the production of virgin filaments. This economic feasibility is essential for the \u0026ldquo;Zero Plastic\u0026rdquo; objective, ensuring that the cost of remediation can be offset by the value of the recycled 3D printer thread\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Functional validation of recycled filament:\u003c/h2\u003e \u003cp\u003eThe challenge of printing with PE and PP, which are prone to warping due to high crystallinity, was addressed through the homogenization of the recovered mix and optimized thermal settings on the Flashforge Adventurer 5M.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the items we have printed with the Flashforge Adventurer 5M 3D printer using the microplastics recovered from the Mediterranean Sea by the AMMRS system, and recycled following the multistep protocol defined in this article:\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe successful fabrication of the items shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (pin, keyring, necklace, and pendant) serves as a physical validation of the recycled filament. Despite the complex origin and potential degradation of marine-aged polymers, the resulting thread maintained a consistent flow through the 0.4 mm nozzle of the Flashforge Adventurer 5M. The printed objects exhibited high layer adhesion and structural integrity at an operating speed of 300 mm/s, demonstrating that the mechanical properties of the marine PE/PP blend are sufficient for producing consumer-grade goods without the need for virgin additives.\u003c/p\u003e \u003cp\u003eThe variety of functional items produced, ranging from industrial fasteners (pins) to aesthetic accessories, highlights the versatility of marine-recycled feedstock. By transforming \u0026ldquo;low-value\u0026rdquo; marine pollutants into \u0026ldquo;high-value\u0026rdquo; customizable goods, the AMMRS framework provides a tangible economic incentive for maritime stakeholders to adopt remediation technologies. The successful printing of fine details indicates that the homogenized marine PE/PP blend can compete with standard filaments in non-structural applications, directly supporting the \u0026ldquo;Zero Plastic\u0026rdquo; objective.\u003c/p\u003e \u003c/div\u003e"},{"header":"5 Discussion","content":"\u003cp\u003eThe characterization of Mediterranean microplastics recovered via the AMMRS confirms the significant abundance of polyolefins (PE and PP), which align with global trends of marine debris. While the 3D printing industry traditionally prioritizes technical polymers like PLA, PETG, and ABS for their ease of use and thermal stability, the sheer volume of PE and PP in the marine environment makes them the most pragmatic candidates for a circular economy. Our results demonstrate that the degradation typically observed in marine-aged plastics, identified through specific FTIR bands such as the carbonyl peaks near 1715 cm⁻\u0026sup1;, did not preclude their mechanical recyclability.\u003c/p\u003e \u003cp\u003eThe economic viability of this process is a key finding. Traditional recycling often suffers from high logistical costs associated with dedicated recovery missions. By utilizing the AMMRS as a passive system on commercial vessels, the marginal cost of recovery is minimized. Furthermore, the mechanical recycling path (densifying and crushing) is significantly more energy-efficient than chemical upcycling. The challenge of printing with PE and PP, which are prone to warping due to high crystallinity, was addressed through the homogenization of the recovered mix and optimized thermal settings on the Flashforge Adventurer 5M.\u003c/p\u003e \u003cp\u003eBy proving that these \"low-value\" marine pollutants can be successfully converted into 3D printing feedstock, this study provides an incentive for the maritime industry to adopt remediation technologies. Future work should explore the inclusion of carbon fibre or fiberglass reinforcements (PETG-CF/PLA-CF) to enhance the structural rigidity of the marine-recycled filament, further bridging the gap between recycled materials and high-performance industrial standards.\u003c/p\u003e \u003cp\u003eThe variety of items produced, ranging from industrial pins to aesthetic jewellery elements, highlights the versatility of marine-recycled feedstock. By transforming 'low-value' marine pollutants into \u0026ldquo;high-value\u0026rdquo; customizable goods, the AMMRS framework provides a tangible incentive for maritime stakeholders. The successful printing of fine details (as seen in the \u0026ldquo;Mar\u0026iacute;a\u0026rdquo; nameplate and pendant geometries) indicates that the homogenized marine PE/PP blend can compete with standard PLA in non-structural applications, further supporting the economic feasibility of the \u0026ldquo;Zero Plastic\u0026rdquo; objective\u003c/p\u003e"},{"header":"6 Conclusions and future perspectives","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows why PE/PP are the pragmatic choice for marine recycling compared to the standard virgin polymers used as 3D printer filaments.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cem\u003eComparison between most used 3D printing filaments and recycled microplastics\u003c/em\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrimary use in 3D printing\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRecovery abundance (AMMRS)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRecovery/Recycling complexity\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePLA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMost popular/Easy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRare in marine surface\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN/A (Virgin source)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePETG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDurable/Versatile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate (as PET fibres)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh (requires high temperature)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePE / PP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIndustrial/Functional\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e70\u0026ndash;80% (Dominant)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow / Economic\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eBy proving that these \u0026ldquo;low-value\u0026rdquo; marine pollutants can be successfully converted into 3D printing feedstock, this study provides a blueprint for turning ocean waste into industrial feedstock. The production of functional prototypes using standard FDM technology validates the entire workflow, from AMMRS recovery to the final object, proving that marine microplastics can be effectively reintegrated into the industrial value chain.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank the company Alser for allowing us to use their separation, crushing, densifying, mixing/homogenizing, extrusion, compositing facilities to process the raw material and help us define the appropriate parameters for recycling microplastics recovered from the ocean.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the B0036-2526/711 project: \u0026ldquo;Reduce, recover, reuse and recycle microplastics from the ocean (zero plastic)\u0026rdquo;, one of the Pre-competitive Research Projects 2025 approved by the Universidad Internacional de La Rioja. The corresponding author Dr. Mar\u0026iacute;a Yoldi is the Principal Researcher of this project, and all the author collaborates in the B0036-2526/711 project.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Dr. Mar\u0026iacute;a Yoldi Sang\u0026uuml;esa. The first draft of the manuscript was written by Dr. Mar\u0026iacute;a Yoldi Sang\u0026uuml;esa and Dr. Luc\u0026iacute;a Grijalvo and Dr. Silvia Jim\u0026eacute;nez commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eWe have not submitted this manuscript to a preprint server before submitting it to \u003cem\u003eScientific Reports\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval*\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate*\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish*\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo data, text, or theories by others are presented as if they were the author\u0026rsquo;s own. Proper acknowledgements to other works must be, quotation marks are used for verbatim copying of material, and permissions secured for material that is copyrighted.\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is not applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e[aist 2025] National Institute of Advanced Industrial Science and Technology (AIST), Spectral Database for Organic Compounds (SDBS) \u0026amp; Available in: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://sdbs.db.aist.go.jp\u003c/span\u003e\u003cspan address=\"https://sdbs.db.aist.go.jp\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e[fan, C. et al. 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Sci. 14(20), 9310; Available in: (2024). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/app14209310\u003c/span\u003e\u003cspan address=\"10.3390/app14209310\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e[Shimadzu 2022] Shimadzi. Excellence in Science. Fourier Transform Infrared Spectrophotometers Support the Identification of Microplastics. Available in: (2022). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.shimadzu.com/today/20220517-1.html#anchor02\u003c/span\u003e\u003cspan address=\"https://www.shimadzu.com/today/20220517-1.html#anchor02\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e[Yoldi 2025] Yoldi, M. From reduction to recovery: integrating passive filtration systems in maritime logistics to close the plastic loop Scientific Reports. Available in: (2025). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://link.springer.com/journal/13762\u003c/span\u003e\u003cspan address=\"https://link.springer.com/journal/13762\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e[Yoldi, M. et al. im\u0026eacute;nez S., Reduce, recover, reuse, and recycle ocean microplastics: a comprehensive approach to marine and terrestrial sustainability Scientific Report. Available in: (2026). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://link.springer.com/journal/13762\u003c/span\u003e\u003cspan address=\"https://link.springer.com/journal/13762\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Marine microplastics, AMMRS, 3D printing filament, mechanical recycling, Mediterranean Sea, polyethylene, polypropylene, circular economy","lastPublishedDoi":"10.21203/rs.3.rs-8709326/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8709326/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMarine microplastic (MP) pollution represents a pervasive environmental crisis, necessitating scalable and economic remediation strategies. This study demonstrates a \u0026ldquo;Zero Plastic\u0026rdquo; circular economy model by integrating the Active Marine Microplastic Remediation System (AMMRS) into the logistics of commercial shipping vessels. This passive filtration technology was utilized to recover MPs from the Mediterranean Sea, which were then characterized and repurposed into functional 3D printing filaments. Characterization via ATR-FTIR and DSC revealed a material profile dominated by Polyethylene (PE) and Polypropylene (PP), constituting 70 to 80% of the recovered mass. A multi-stage mechanical recycling workflow, comprising densifying, crushing, and extrusion, was developed to transform these degraded marine polymers into standardized threads. Despite the prevalence of PLA and PETG in the 3D printing market, our findings validate that recycled marine PE and PP offer a highly economic and technically viable alternative. The feasibility of this circular approach was confirmed by the successful production of various functional prototypes, including industrial pins and aesthetic accessories, using a standard FDM printer (Flashforge Adventurer 5M). This research provides a tangible blueprint for turning ocean waste into industrial feedstock, supporting both marine conservation and sustainable additive manufacturing.\u003c/p\u003e","manuscriptTitle":"3D Printer Thread Manufacturing From Microplastics Recovered From the Ocean","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-02 06:24:15","doi":"10.21203/rs.3.rs-8709326/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"253b0c17-b7db-4753-af86-b3e95fd3f2d3","owner":[],"postedDate":"February 2nd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":62131210,"name":"Physical sciences/Engineering"},{"id":62131211,"name":"Earth and environmental sciences/Environmental sciences"},{"id":62131212,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2026-02-10T07:11:42+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-02 06:24:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8709326","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8709326","identity":"rs-8709326","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}