Preparation of high-performance CGF/PVC laminates: optimization of compression molding process parameters

Preparation of high-performance CGF/PVC laminates: optimization of compression molding process parameters | 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 Research Article Preparation of high-performance CGF/PVC laminates: optimization of compression molding process parameters Zetian Hua, Run Zhang, Chenchao Fu, Lin Jiang, Mingfei Liu, Ping Xue This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6598139/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Aug, 2025 Read the published version in Journal of Polymer Research → Version 1 posted 5 You are reading this latest preprint version Abstract In this paper, CGF/PVC composite prepreg is prepared by dry powder impregnation process, and then, on this basis, the preparation of CGF/PVC laminates are further accomplished by compression molding. The optimum hot pressing process conditions for the preparation of CGF/PVC laminates by compression molding are determined through the continuous optimization of parameters such as temperature, pressure and time at the hot pressing stage by the one-factor-variable method. When the hot pressing temperature, hot pressing pressure and hot pressing time are 180 ℃, 7 MPa and 12 min, respectively, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of CGF/PVC laminates prepared at this time are 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m 2 , respectively. This study not only provides a process optimization strategy for the preparation of CGF/PVC composites by compression molding, but also further provides important theoretical and practical guidance for the industrial production of high-performance CGF/PVC composites. CGF/PVC compression molding surface quality mechanical properties microscopic morphology Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Continuous glass fiber reinforced polyvinyl chloride (CGF/PVC) composites are a kind of continuous fiber reinforced thermoplastic composites (CFRTPC) prepared by specific impregnation process and molding process with CGF as the reinforcement and PVC resin as the matrix. Compared with other CFRTPC, it is not only more competitive in terms of raw material and production cost, but also has excellent performance in terms of flame retardancy, insulation, corrosion resistance, and aging resistance. 1 – 6 With the continuous expansion of CFRTPC in high-end application scenarios in recent years, various industries have put forward higher requirements for the performance of CFRTPC. 7 – 11 However, CGF/PVC composites face many difficulties and challenges in molding due to the characteristics of high viscosity of PVC resin melt, difficult to plasticize, and poor thermal stability, which make the molding difficulty far more than that of other traditional CFRTPC, especially in meeting the demand for high performance. 12 – 15 Currently, the main molding processes for CFRTPC include compression molding, winding molding, pultrusion molding, and 3D printing molding, etc. 16 – 22 Compared with other molding processes, compression molding has the advantages of simple process, short production cycle, low production cost, high production efficiency, and controllable material properties, which has been gradually and widely used for molding a variety of CFRTPC products. 23 In the CFRTPC compression molding process, a CFRTPC prepreg of a specific size is first placed in a mold, and after closing the mold, it is moved to a preheated and completed compression molding machine, and a certain pressure is applied to it to ensure sufficient infiltration of the fiber by the molten resin. When a predetermined holding and pressure holding time is reached, the resin is finally cured by cold pressing, thereby forming a structurally stable CFRTPC product. Shi et al. 24 used an innovative compression molding method to achieve the preparation of high-performance CFRTPC with a fiber volume fraction of nearly 60%. Enoki et al. 25 investigated the effect of maleic anhydride-modified polypropylene (m-PP) on the mechanical properties of the compression molding-prepared CF/PP laminates, and the experimental data showed that the tensile strength of the CF/PP laminates could reach 700 MPa with the addition of 12.5 wt% of m-PP. In the entire compression molding process, hot pressing, as the most critical stage of material molding, also has a crucial impact on the properties of the final prepared material. In the hot pressing stage, the cured resin, under the synergistic effect of high temperature and high pressure, will melt again and obtain a certain melt flow rate, so as to realize the second impregnation of the fiber, which forms a closer interfacial bonding with the fiber bundles, thus making the overall performance and structural homogeneity of the finally prepared material significantly improved. Therefore, based on the above research background, this paper adopts compression molding to complete the preparation of CGF/PVC laminates on the basis of CGF/PVC composite prepreg prepared by dry powder impregnation process, and in this process, the temperature, pressure and time of the hot pressing stage are systematically regulated in order to reveal the influencing mechanism of the change of these parameters on the performance of CGF/PVC laminates. This will provide an important theoretical basis for the preparation of CGF/PVC composites by compression molding, and at the same time further provide practical guidance for the development and production of high-performance CGF/PVC composites. 2. Experimental 2.1 Materials The raw materials used in this experimental study included: PVC resin powder (SG-8), CGF (ECT 4305PM-1200), calcium-zinc stabilizer (HJ-615), and plasticizer (S60-A), of which the PVC resin powder was purchased from Shanxi Beiyuan Chemical Group Co., Ltd., Shanxi, China, the CGF was purchased from Chongqing International Composites Co., Ltd., Chongqing, China, the calcium-zinc stabilizer was provided by Anhui Huajie Hengye New Material Technology Co., Ltd., Anhui, China, and the plasticizer was provided by Suzhou Ningsheng Chemical Co., Ltd., Jiangsu, China. The particle size of the PVC resin powder was 200 mesh, and the glass transition temperature was 81.6 ℃. the CGF yarn density was 1200 tex, the yarn diameter was 16 µm. 2.2 Material preparation First of all, the CGF placed on the yarn frame, under the action of the pulling device (DO-750, Shanghai Weilian Extrusion Machinery Co., Ltd., Shanghai, China.), was guided to the spreader (homemade in the laboratory) to achieve the unfolding of the fiber bundles, and after the unfolding of the fiber bundles, the fiber bundles would be humidified by a humidifier to make the fiber electrically conductive. Then, the PVC formulation was coated on the fiber by electrostatic powder spraying device (RL-A5, Yangzhou Zhigao Machinery Manufacturing Co., Ltd., Jiangsu, China.), and melted by the heater (homemade in the laboratory) to gradually achieve a complete coating of the entire fiber surface. Finally, it was further compacted under the action of a three-roller press (homemade in the laboratory), thus completing the whole preparation process of CGF/PVC composite prepreg, as shown in Fig. 1 a. Immediately after that, the prepared CGF/PVC composite prepreg, cut to specific size, was placed in a mold (homemade in the laboratory) for layer-by-layer stacking. After the layers reached a predetermined thickness, the mold could be closed and transferred to the hot pressing chamber of the compression molding machine (CREE-6014C-30, Dongguan Kerui Instrument Technology Co., Ltd., Guangdong, China.), which had been preheated in advance, for pressing. When the predetermined holding and pressure holding time was reached, the mold was taken out and moved to the cold pressing chamber of the compression molding machine for cooling and shaping. When the cold pressing was finished, the mold was opened, and after some necessary post-processing, the CGF/PVC laminate required for the experiment could be obtained, and the whole compression molding process was shown in Fig. 1 b. 2.3 Performance characterization Firstly, the microscopic morphology of the CGF/PVC laminates surface was initially observed by scanning electron microscope (S-4800, HITACHI, Japan), and then the surface roughness was further determined by atomic force microscope (DMFASTSCAN2-SYS, BRUKER, USA), so as to carry out a detailed characterization of the surface quality of the CGF/PVC laminates. The prepared CGF/PVC laminates were tested for tensile strength, flexural strength, interlaminar shear strength and notched impact toughness using a universal testing machine (WDT-W, Chengde Precision Testing Machine Co., Ltd., Hebei, China.) and an impact testing machine (WDT-W, Chengde Precision Testing Machine Co., Ltd., Hebei, China.) according to the determination methods described in standards GB/T1447-2005, GB/T1449-2005, JC/T773-2010 and GB/T1451-2005, respectively. where the interlaminar shear strength τ L and notched impact toughness a L of CGF/PVC laminates were finally calculated by Eq. 1 and Eq. 2, respectively: Where: τ L -CGF/PVC laminates interlaminar shear strength, MPa; F -breaking load, N; W -CGF/PVC laminates specimen width, mm; T -CGF/PVC laminates specimen thickness, mm. Where: a L -CGF/PVC laminates notched impact toughness, kJ/m 2 ; A -punching off the CGF/PVC laminates specimen consumed work, J; b -CGF/PVC laminates specimen notched width, mm; d -CGF/PVC laminates specimen notched minimum thickness, mm. 3. Results and discussion 3.1 Hot pressing temperature analysis The CGF/PVC laminates prepared at different hot pressing temperatures are shown in Fig. 2 , at which the hot pressing pressure and hot pressing time are fixed at 4 MPa and 6 min, respectively. As can be seen in Fig. 2 , with the gradual increase of the hot pressing temperature from 170 ℃ to 190 ℃, the appearance color of CGF/PVC laminates gradually transitions from the initial white to orange-yellow. This change in the color of the appearance of CGF/PVC laminates is a reflection of a continuous and intensified process of thermal decomposition of the PVC resin. Normally, the initial decomposition temperature of pure PVC resin is about 200 ℃, but in the actual processing, due to the combined effect of multiple factors such as temperature, pressure and time, the decomposition of PVC resin may occur earlier. Thermal decomposition of PVC resin involves a complex chain reaction process, the reaction of its entire reaction process can be roughly divided into the following three stages: 26 – 28 (1) synergistic dechlorination; (2) self-catalyzed, continuous dechlorination of HCl; (3) cyclization, cross-linking and carbonization. In the stage of “synergistic dechlorination”, the chlorine and hydrogen atoms in the unstable structures of the PVC molecular chain structure (e.g., allyl chloride, tertiary carbon chloride, etc.) are simultaneously removed from the neighboring carbon atoms to form a short-chain conjugated polyene structure and release HCl: And as the de-HCl reaction continues, the generated HCl acts as a catalyst to promote the continuous dechlorination reaction, the reaction rate of which rises with the increase of HCl concentration. At this time, the length (n) of the double bond in the conjugated polyene structure gradually increases and is thus extended into a conjugated polyene sequence: Eventually, as the PVC decomposition reaction continues, the conjugated polyene structure undergoes cyclization, cross-linking and other reactions to generate polycyclic aromatic hydrocarbons (PAHs), accompanied by the generation of carbons: In the above study, when the hot pressing temperature is low, the overall color of the CGF/PVC laminates surface shows a relatively uniform white color, as shown in Fig. 2 a and Fig. 2 b, indicating that the PVC resin has not yet produced significant thermal decomposition phenomenon at this time. When the hot pressing temperature rises to 180 ℃, CGF/PVC laminates begin to show slight yellowing in local areas, as shown in Fig. 2 c, which indicates that at this time, the PVC resin has begun to initially decompose and accompanied by the release of a trace amount of HCl, and at the same time triggered the formation of the conjugated polyene structure. However, at this time, due to the short length of the double bond in the conjugated chain formed, it only absorbs the ultraviolet light in the visible light, so the macroscopic color change of the surface of CGF/PVC laminates is not obvious yet. When the hot pressing temperature reaches 185 ℃, the color of CGF/PVC laminates further deepens and shows obvious yellow color, as shown in Fig. 2 d, indicating that the PVC resin has entered the stage of continuous dehydrogenation at this time, and the length of the double bond in the conjugated chain is further extended. Finally, when the hot pressing temperature is increased to 190 ℃, the yellow color of CGF/PVC laminates is expanded to the whole surface and further changed to orange-yellow color, as shown in Fig. 2 e. At this point, the overall mechanical properties of the prepared CGF/PVC laminates may have deteriorated to some extent due to degradation of the PVC resin. Therefore, in order to verify the above conjecture, the mechanical properties of CGF/PVC laminates prepared with different hot pressing temperatures are further investigated. Figure 3 shows the influence of different hot pressing temperatures on the mechanical properties of the prepared CGF/PVC laminates, from which it can be seen that, with the increasing hot pressing temperature, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the CGF/PVC laminates show a tendency of increasing and then decreasing, and all of them reach a great value when the hot pressing temperature is 180 ℃, with the values of 212.16 MPa, 196.12 MPa, 20.53 MPa and 145.45 kJ/m 2 , respectively. In the hot pressing temperature 170 ~ 180 ℃ range of this interval, has been cured PVC resin will begin to soften again, and with the increasing temperature and gradually reach a better molten state, in the joint action of the pressure to achieve the second infiltration of the fiber. At this time, the physical occlusion between the fiber and the resin matrix will be further strengthened, which can effectively improve the load transfer efficiency, so that the overall mechanical properties of the material to a greater extent. When the hot pressing temperature exceeds 180 ℃, the PVC resin gradually begins to decompose, and as the temperature continues to rise, the de-HCl reaction continues to intensify, which leads to the accumulation of conjugated polyene structures. These accumulated conjugated polyene structures not only weaken the toughness of the resin matrix, but also form stress concentration points at the fiber-resin matrix interface. Ultimately, the tensile strength, flexural strength, interlaminar shear strength, and notched impact toughness of the prepared CGF/PVC laminates are reduced by 6.7%, 5.7%, 10.4%, and 7.0%, respectively, compared with the optimal values when the hot pressing temperature reached 190 ℃. 3.2 Hot pressing pressure analysis As another important process parameter of compression molding, the size of the hot pressing pressure also has an important influence on the properties of the prepared CGF/PVC laminates. Figure 4 shows the influence of different hot pressing pressure on the mechanical properties of the prepared CGF/PVC laminates, at which the hot pressing temperature and hot pressing time are fixed at 180 ℃ and 6 min, respectively. It can be seen from Fig. 4 that with the increasing of hot pressing pressure in a certain range (4 ~ 7 MPa), the mechanical properties of CGF/PVC laminates maintain a continuous elevation trend. When the hot pressing pressure reaches 7 MPa, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the CGF/PVC laminates prepared at this time are 236.52 MPa, 229.39 MPa, 23.06 MPa and 167.13 kJ/m 2 , respectively, which increase 11.5%, 17.0%, 12.3% and 14.9%, respectively, compared with the mechanical properties of the CGF/PVC laminates corresponding to the CGF/PVC laminates prepared with a hot pressing pressure of 4 MPa. When the hot pressing pressure is further increased to 8 MPa, the mechanical properties of CGF/PVC laminates prepared at this time began to show a decreasing trend. At a lower hot pressing pressure (4 MPa), although some of the fibers in the prepared CGF/PVC laminates have achieved a preliminary bonding with the PVC resin matrix, some tiny voids still existed in the laminated layers due to the limited pressure. At this time, the PVC resin does not achieve a good infiltration effect on the fiber, as shown in Fig. 5 a. With the increasing pressure of hot pressing (5 ~ 7 MPa), a closer interfacial bond between PVC resin matrix and fiber is gradually formed, as shown in Fig. 5 b, Fig. 5 c and Fig. 5 d. At this time, the tiny gaps existing between the layers of CGF/PVC laminates are effectively compressed and discharged, and the interfacial defects are reduced significantly, which enhances the overall mechanical properties of the material to a certain extent. However, when the hot pressing pressure reaches 8 MPa, the PVC resin is over-extruded at this pressure value, which results in uneven distribution of the resin matrix and insufficient impregnation in localized areas of the interface, as shown in Fig. 5 e, which ultimately affects the overall mechanical properties of the material. In addition, it is found that the surface quality of CGF/PVC laminates gradually shows a better level with the increasing of the hot pressing pressure by observing the surface microscopic morphology of CGF/PVC laminates prepared under different hot pressing pressures and determining the surface roughness value. When the hot pressing pressure is only 4 MPa, due to the high viscosity of the PVC melt, it is not possible to achieve effective flow under this pressure, resulting in poor secondary impregnation of the fiber to the extent that obvious microscopic defects appear on the surface of the material, as shown in Fig. 6 a, and the surface roughness as a whole is also at a high value, as shown in Fig. 7 a. With the hot pressing pressure increased to 5 MPa, this time the material surface quality has been improved to some extent, but a variety of microscopic defects are still more obvious, as shown in Fig. 6 b, corresponding to the surface roughness still has a large value, as shown in Fig. 7 b. When the hot pressing pressure continues to increase to 6 MPa, the material surface has no obvious microscopic defects, as shown in Fig. 6 c, but the surface flatness is still to be further improved, as shown in Fig. 7 c. Eventually, when the hot pressing pressure is further increased to 7 MPa and 8 MPa, the surface of the material is smooth and flat at this time, and a few fiber rows can be observed, as shown in Fig. 6 d and Fig. 6 e, and the corresponding maximum values of the surface roughness are kept at a level of less than 100 nm, as shown in Fig. 7 d and Fig. 7 e. However, when the hot pressing pressure is 8 MPa, the number of fibers on the surface of the material can be observed to increase, and it can be clearly observed that the fibers appear to be irregularly arranged, and this phenomenon will lead to the material force, the stress is not uniformly transmitted in the interior of the material, which will have a certain negative impact on the overall mechanical properties of the material. 3.3 Hot pressing time analysis In the compression molding process, hot pressing temperature, hot pressing pressure and hot pressing time work together to determine the final properties of the material. Only when the hot pressing temperature is sufficient to melt the resin matrix, the hot pressing pressure can realize good compaction and the hot pressing time is set reasonably, the final material properties can be optimized. Therefore, in this subsection, based on the optimal hot pressing temperature of 180 ℃ and hot pressing pressure of 7 MPa determined above, an in-depth investigation of the hot pressing time is carried out, so as to achieve the purpose of continuous optimization of the properties of the prepared CGF/PVC laminates. The effects of different hot pressing times on the mechanical properties of the prepared CGF/PVC laminates are shown in Fig. 8 . As can be seen from Fig. 8 , when the hot pressing time is increasing in the range of 6 ~ 12 min, the mechanical properties of the material show a continuous increasing trend. Finally, when the hot pressing time is 12 min, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the material reach a great value of 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m 2 , respectively, which increase 6.8%, 7.6%, 10.1% and 5.0%, respectively, compared to the mechanical properties of the CGF/PVC laminates prepared with a hot pressing time of 6 min. After the hot pressing time exceeds 12 min, the mechanical properties of the material begin to decrease continuously. Finally, when the hot pressing time increases to 18 min, the mechanical properties of the CGF/PVC laminates prepared at this time decrease to 241.27 MPa, 233.41 MPa, 23.92 MPa, and 169.78 kJ/m 2 , respectively. Compared with their optimal mechanical properties, the degree of decrease is 4.5%, 5.4%, 5.8%, and 4.0%, respectively. Since PVC is a thermoplastic resin, its melting behavior is governed by a combination of temperature and time. At the beginning of the hot pressing stage, PVC resin needs to absorb enough heat to overcome the glass transition temperature (Tg = 81.6°C) and enter the viscoelastic state. If the hot pressing time is too short, the resin does not melt sufficiently and the viscosity is too high, which makes it difficult to effectively infiltrate the fiber, thus leading to poor overall mechanical properties of the material. With the increasing hot pressing time, the PVC resin matrix has more time to fully melt and flow under the high temperature and high pressure environment, so that it can better infiltrate the fiber and form a good interfacial bond with the fiber, which makes the overall mechanical properties of the material continue to improve. However, when the hot pressing time exceeds a certain threshold, while further extension of the time allows for continuous compaction of the material under high temperature and high pressure conditions, it also poses the risk of localized overheating or degradation, which can lead to adverse effects on the properties of the final prepared material. 3.4 Comparison of GF/PVC composites properties It is found through the above study that controlling the temperature, pressure and time of the hot pressing stage at 180 ℃, 7 MPa and 12 min, respectively, during the compression molding process for the preparation of SG-8 CGF/PVC laminates is an optimal process condition, at which time the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the prepared composites are 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m 2 , which is a high level compared with domestic and international studies. Compared to the fiber-less reinforced PVC sheets prepared under the same experimental, process, and additive conditions, the corresponding mechanical properties (59.21 MPa, 76.63 MPa, 6.89 MPa, and 87.71 kJ/m 2 ) are improved by 326.7%, 222.0%, 268.4% and 101.6%, respectively. Comparison of this study with typical domestic and international studies on the properties of GF/PVC composites is shown in Table 1 . Table 1 Comparison of properties of GF/PVC composites Author Tensile strength (MPa) Flexural strength (MPa) Interlaminar shear strength (MPa) Impact toughness (kJ/m 2 ) Park et al. 29 328.48 93.30 7.98 - Wang et al. 30 345 302 28.2 199 Khan et al. 31 65 68 4.66 33 Lee et al. 32 330 ~ 340 95 ~ 100 8 ~ 8.5 - Wang et al. 33 45.6 80.8 - 4.97 Nguyen et al. 34 - 229 - - The study 252.65 246.73 25.38 176.79 4. Conclusions In this paper, the preparation of CGF/PVC laminates are accomplished by compression molding process, in which the effects of three parameters, namely, temperature, pressure and time, on the properties of CGF/PVC laminates at the stage of hot pressing are analyzed, and the mechanism of thermal decomposition of PVC is also elaborated in detail, and the main conclusions of the study are as follows: When the hot pressing temperature, hot pressing pressure and hot pressing time are controlled to be 180 ℃, 7 MPa and 12 min, respectively, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of CGF/PVC laminates prepared at this time have an optimum value of 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m 2 , respectively. Compared to the fiber-less reinforced PVC sheets prepared under the same experimental, process and additive conditions, the corresponding mechanical properties are improved by 326.7%, 222.0%, 268.4% and 101.6%, respectively. Declarations Conflict of Interest The authors declare no competing financial interest. Author Contributions Zetian Hua : Writing – original draft (lead); investigation (lead). Run Zhang : Supervision (lead); writing – review and editing (lead). Chenchao Fu : Supervision (equal). Lin Jiang : writing – review and editing (equal). Mingfei Liu : writing – review and editing (equal). Ping Xue : Resources (lead); supervision (equal). Acknowledgment The authors would like to acknowledge the support of the Analysis and Test Center of Beijing University of Chemical Technology. Data Availability Statement Data available on request from the authors. References Pan Y T, Yuan Y, Wang D Y, et al. 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Cite Share Download PDF Status: Published Journal Publication published 11 Aug, 2025 Read the published version in Journal of Polymer Research → Version 1 posted Reviewers agreed at journal 15 May, 2025 Reviewers invited by journal 15 May, 2025 Editor invited by journal 09 May, 2025 Editor assigned by journal 06 May, 2025 First submitted to journal 06 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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Hua","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuUlEQVRIie3QsQrCMBCA4ZRAspxkTajoK2QToeirHAiZ3F0DhU4+QH2RzilCR91cXHRxbre6GfAFrptg/uWW+4Y7xlKpH0zzIOIoQClPJQIjQTc3dZhGzoX1SCSmkrfne7yCZSHrhz2B5AIOVuMdVtxzc2oIZLE8Om0jWfsg+IxEBDiNeAEbkEhyITsdMEwgpgJhvNuBqduSdovu5MuMxWarVNn2A4UwFt/7LfOk/Zh8UDdTqVTqX/sAaYkxdCJqwxsAAAAASUVORK5CYII=","orcid":"https://orcid.org/0009-0008-3805-6997","institution":"Beijing University of Chemical Technology","correspondingAuthor":true,"prefix":"","firstName":"Zetian","middleName":"","lastName":"Hua","suffix":""},{"id":457328947,"identity":"40d448aa-7f41-412e-867b-2ff9b1e00748","order_by":1,"name":"Run Zhang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Run","middleName":"","lastName":"Zhang","suffix":""},{"id":457328948,"identity":"015fcafb-2ea3-427e-b8d1-680666c1a225","order_by":2,"name":"Chenchao Fu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Chenchao","middleName":"","lastName":"Fu","suffix":""},{"id":457328949,"identity":"831d4976-2ec3-4286-bedd-bc800964344b","order_by":3,"name":"Lin Jiang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Lin","middleName":"","lastName":"Jiang","suffix":""},{"id":457328950,"identity":"c5f1d35c-afa5-4bb8-9441-be199ee34780","order_by":4,"name":"Mingfei Liu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Mingfei","middleName":"","lastName":"Liu","suffix":""},{"id":457328951,"identity":"d0193560-79b1-4b06-b1c9-70fe4b6b42db","order_by":5,"name":"Ping Xue","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Ping","middleName":"","lastName":"Xue","suffix":""}],"badges":[],"createdAt":"2025-05-06 02:12:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6598139/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6598139/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10965-025-04509-7","type":"published","date":"2025-08-11T15:58:09+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":83105886,"identity":"9fdf4352-8357-434a-9afd-e1fc0b0f660d","added_by":"auto","created_at":"2025-05-20 06:13:04","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":228308,"visible":true,"origin":"","legend":"\u003cp\u003eCGF/PVC composites preparation (a) CGF/PVC composite prepreg preparation (b) CGF/PVC laminates preparation\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/3924cfce4046c225489f4ec1.png"},{"id":83106939,"identity":"0142374d-e197-4db7-9eec-f18855fbe5e9","added_by":"auto","created_at":"2025-05-20 06:29:04","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":90617,"visible":true,"origin":"","legend":"\u003cp\u003eCGF/PVC laminates prepared at different hot pressing temperatures (a) 170 °C (b) 175 °C (c) 180 °C (d) 185 °C (e) 190 °C\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/d65eb184ecd08cb297b551ce.png"},{"id":83106229,"identity":"dca98214-7d0a-4fa6-86f5-885262abd5bf","added_by":"auto","created_at":"2025-05-20 06:21:04","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":153940,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of hot pressing temperature on mechanical properties of CGF/PVC laminates (a) Tensile and flexural properties (b) Interlaminar shear and impact properties\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/3996620a4631f3a011532935.png"},{"id":83106232,"identity":"6120d9bc-1647-4cac-bf95-bce70f65eae4","added_by":"auto","created_at":"2025-05-20 06:21:04","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":172375,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of hot pressing pressure on mechanical properties of CGF/PVC laminates (a) Tensile and flexural properties (b) Interlaminar shear and impact properties\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/ba8f330fb479222f8301e8b3.png"},{"id":83106945,"identity":"4749dce3-6d94-441f-8ac3-5c5525c4b67e","added_by":"auto","created_at":"2025-05-20 06:29:04","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":249120,"visible":true,"origin":"","legend":"\u003cp\u003eInterfacial microscopic morphology of CGF/PVC laminates prepared by different hot pressing pressures (a) 4 MPa (b) 5 MPa (c) 6 MPa (d) 7 MPa (e) 8 MPa\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/a33357eb2405c4c8b4557bf4.png"},{"id":83106940,"identity":"737adc8c-99e0-4c55-8386-a1080fa71512","added_by":"auto","created_at":"2025-05-20 06:29:04","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":255232,"visible":true,"origin":"","legend":"\u003cp\u003eSurface microscopic morphology of CGF/PVC laminates prepared by different hot pressing pressures (a) 4 MPa (b) 5 MPa (c) 6 MPa (d) 7 MPa (e) 8 MPa\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/785dad6fa2d85d144ba71d0c.png"},{"id":83105906,"identity":"25c3a1ab-8598-43dd-9ec4-0ecd673ec078","added_by":"auto","created_at":"2025-05-20 06:13:04","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":205769,"visible":true,"origin":"","legend":"\u003cp\u003eSurface roughness of CGF/PVC laminates prepared by different hot pressing pressure (a) 4 MPa (b) 5 MPa (c) 6 MPa (d) 7 MPa (e) 8 MPa\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/ab4e654eb05ef4bdcae9327a.png"},{"id":83105893,"identity":"c4bf6edd-12ba-4f81-afa7-c04e00380cbe","added_by":"auto","created_at":"2025-05-20 06:13:04","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":167996,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of hot pressing time on mechanical properties of CGF/PVC laminates (a) Tensile and flexural properties (b) Interlaminar shear and impact properties\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/7f6a64972b540cca9b073536.png"},{"id":89311120,"identity":"ec6b849e-5a8c-48bc-81bb-220bc8d735cf","added_by":"auto","created_at":"2025-08-18 16:10:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2176817,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6598139/v1/dbad27f6-3193-4797-a5cb-4695667494f5.pdf"}],"financialInterests":"","formattedTitle":"Preparation of high-performance CGF/PVC laminates: optimization of compression molding process parameters","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eContinuous glass fiber reinforced polyvinyl chloride (CGF/PVC) composites are a kind of continuous fiber reinforced thermoplastic composites (CFRTPC) prepared by specific impregnation process and molding process with CGF as the reinforcement and PVC resin as the matrix. Compared with other CFRTPC, it is not only more competitive in terms of raw material and production cost, but also has excellent performance in terms of flame retardancy, insulation, corrosion resistance, and aging resistance.\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWith the continuous expansion of CFRTPC in high-end application scenarios in recent years, various industries have put forward higher requirements for the performance of CFRTPC.\u003csup\u003e\u003cspan additionalcitationids=\"CR8 CR9 CR10\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e However, CGF/PVC composites face many difficulties and challenges in molding due to the characteristics of high viscosity of PVC resin melt, difficult to plasticize, and poor thermal stability, which make the molding difficulty far more than that of other traditional CFRTPC, especially in meeting the demand for high performance.\u003csup\u003e\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eCurrently, the main molding processes for CFRTPC include compression molding, winding molding, pultrusion molding, and 3D printing molding, etc.\u003csup\u003e\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20 CR21\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e Compared with other molding processes, compression molding has the advantages of simple process, short production cycle, low production cost, high production efficiency, and controllable material properties, which has been gradually and widely used for molding a variety of CFRTPC products.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn the CFRTPC compression molding process, a CFRTPC prepreg of a specific size is first placed in a mold, and after closing the mold, it is moved to a preheated and completed compression molding machine, and a certain pressure is applied to it to ensure sufficient infiltration of the fiber by the molten resin. When a predetermined holding and pressure holding time is reached, the resin is finally cured by cold pressing, thereby forming a structurally stable CFRTPC product. Shi et al.\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e used an innovative compression molding method to achieve the preparation of high-performance CFRTPC with a fiber volume fraction of nearly 60%. Enoki et al.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e investigated the effect of maleic anhydride-modified polypropylene (m-PP) on the mechanical properties of the compression molding-prepared CF/PP laminates, and the experimental data showed that the tensile strength of the CF/PP laminates could reach 700 MPa with the addition of 12.5 wt% of m-PP.\u003c/p\u003e \u003cp\u003eIn the entire compression molding process, hot pressing, as the most critical stage of material molding, also has a crucial impact on the properties of the final prepared material. In the hot pressing stage, the cured resin, under the synergistic effect of high temperature and high pressure, will melt again and obtain a certain melt flow rate, so as to realize the second impregnation of the fiber, which forms a closer interfacial bonding with the fiber bundles, thus making the overall performance and structural homogeneity of the finally prepared material significantly improved.\u003c/p\u003e \u003cp\u003eTherefore, based on the above research background, this paper adopts compression molding to complete the preparation of CGF/PVC laminates on the basis of CGF/PVC composite prepreg prepared by dry powder impregnation process, and in this process, the temperature, pressure and time of the hot pressing stage are systematically regulated in order to reveal the influencing mechanism of the change of these parameters on the performance of CGF/PVC laminates. This will provide an important theoretical basis for the preparation of CGF/PVC composites by compression molding, and at the same time further provide practical guidance for the development and production of high-performance CGF/PVC composites.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eThe raw materials used in this experimental study included: PVC resin powder (SG-8), CGF (ECT 4305PM-1200), calcium-zinc stabilizer (HJ-615), and plasticizer (S60-A), of which the PVC resin powder was purchased from Shanxi Beiyuan Chemical Group Co., Ltd., Shanxi, China, the CGF was purchased from Chongqing International Composites Co., Ltd., Chongqing, China, the calcium-zinc stabilizer was provided by Anhui Huajie Hengye New Material Technology Co., Ltd., Anhui, China, and the plasticizer was provided by Suzhou Ningsheng Chemical Co., Ltd., Jiangsu, China. The particle size of the PVC resin powder was 200 mesh, and the glass transition temperature was 81.6 ℃. the CGF yarn density was 1200 tex, the yarn diameter was 16 \u0026micro;m.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Material preparation\u003c/h2\u003e \u003cp\u003eFirst of all, the CGF placed on the yarn frame, under the action of the pulling device (DO-750, Shanghai Weilian Extrusion Machinery Co., Ltd., Shanghai, China.), was guided to the spreader (homemade in the laboratory) to achieve the unfolding of the fiber bundles, and after the unfolding of the fiber bundles, the fiber bundles would be humidified by a humidifier to make the fiber electrically conductive. Then, the PVC formulation was coated on the fiber by electrostatic powder spraying device (RL-A5, Yangzhou Zhigao Machinery Manufacturing Co., Ltd., Jiangsu, China.), and melted by the heater (homemade in the laboratory) to gradually achieve a complete coating of the entire fiber surface. Finally, it was further compacted under the action of a three-roller press (homemade in the laboratory), thus completing the whole preparation process of CGF/PVC composite prepreg, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea.\u003c/p\u003e \u003cp\u003eImmediately after that, the prepared CGF/PVC composite prepreg, cut to specific size, was placed in a mold (homemade in the laboratory) for layer-by-layer stacking. After the layers reached a predetermined thickness, the mold could be closed and transferred to the hot pressing chamber of the compression molding machine (CREE-6014C-30, Dongguan Kerui Instrument Technology Co., Ltd., Guangdong, China.), which had been preheated in advance, for pressing. When the predetermined holding and pressure holding time was reached, the mold was taken out and moved to the cold pressing chamber of the compression molding machine for cooling and shaping. When the cold pressing was finished, the mold was opened, and after some necessary post-processing, the CGF/PVC laminate required for the experiment could be obtained, and the whole compression molding process was shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Performance characterization\u003c/h2\u003e \u003cp\u003eFirstly, the microscopic morphology of the CGF/PVC laminates surface was initially observed by scanning electron microscope (S-4800, HITACHI, Japan), and then the surface roughness was further determined by atomic force microscope (DMFASTSCAN2-SYS, BRUKER, USA), so as to carry out a detailed characterization of the surface quality of the CGF/PVC laminates.\u003c/p\u003e \u003cp\u003eThe prepared CGF/PVC laminates were tested for tensile strength, flexural strength, interlaminar shear strength and notched impact toughness using a universal testing machine (WDT-W, Chengde Precision Testing Machine Co., Ltd., Hebei, China.) and an impact testing machine (WDT-W, Chengde Precision Testing Machine Co., Ltd., Hebei, China.) according to the determination methods described in standards GB/T1447-2005, GB/T1449-2005, JC/T773-2010 and GB/T1451-2005, respectively. where the interlaminar shear strength \u003cem\u003eτ\u003c/em\u003e\u003csub\u003e\u003cem\u003eL\u003c/em\u003e\u003c/sub\u003e and notched impact toughness \u003cem\u003ea\u003c/em\u003e\u003csub\u003e\u003cem\u003eL\u003c/em\u003e\u003c/sub\u003e of CGF/PVC laminates were finally calculated by Eq.\u0026nbsp;1 and Eq.\u0026nbsp;2, respectively:\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"366\" height=\"39\"\u003e\u003c/p\u003e \u003cp\u003eWhere: \u003cem\u003eτ\u003c/em\u003e\u003csub\u003e\u003cem\u003eL\u003c/em\u003e\u003c/sub\u003e-CGF/PVC laminates interlaminar shear strength, MPa; \u003cem\u003eF\u003c/em\u003e-breaking load, N; \u003cem\u003eW\u003c/em\u003e-CGF/PVC laminates specimen width, mm; \u003cem\u003eT\u003c/em\u003e-CGF/PVC laminates specimen thickness, mm.\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"360\" height=\"31\"\u003e\u003c/p\u003e \u003cp\u003eWhere: \u003cem\u003ea\u003c/em\u003e\u003csub\u003e\u003cem\u003eL\u003c/em\u003e\u003c/sub\u003e-CGF/PVC laminates notched impact toughness, kJ/m\u003csup\u003e2\u003c/sup\u003e; \u003cem\u003eA\u003c/em\u003e-punching off the CGF/PVC laminates specimen consumed work, J; \u003cem\u003eb\u003c/em\u003e-CGF/PVC laminates specimen notched width, mm; \u003cem\u003ed\u003c/em\u003e-CGF/PVC laminates specimen notched minimum thickness, mm.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Hot pressing temperature analysis\u003c/h2\u003e \u003cp\u003eThe CGF/PVC laminates prepared at different hot pressing temperatures are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, at which the hot pressing pressure and hot pressing time are fixed at 4 MPa and 6 min, respectively. As can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, with the gradual increase of the hot pressing temperature from 170 ℃ to 190 ℃, the appearance color of CGF/PVC laminates gradually transitions from the initial white to orange-yellow. This change in the color of the appearance of CGF/PVC laminates is a reflection of a continuous and intensified process of thermal decomposition of the PVC resin.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eNormally, the initial decomposition temperature of pure PVC resin is about 200 ℃, but in the actual processing, due to the combined effect of multiple factors such as temperature, pressure and time, the decomposition of PVC resin may occur earlier. Thermal decomposition of PVC resin involves a complex chain reaction process, the reaction of its entire reaction process can be roughly divided into the following three stages:\u003csup\u003e\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e (1) synergistic dechlorination; (2) self-catalyzed, continuous dechlorination of HCl; (3) cyclization, cross-linking and carbonization.\u003c/p\u003e \u003cp\u003eIn the stage of \u0026ldquo;synergistic dechlorination\u0026rdquo;, the chlorine and hydrogen atoms in the unstable structures of the PVC molecular chain structure (e.g., allyl chloride, tertiary carbon chloride, etc.) are simultaneously removed from the neighboring carbon atoms to form a short-chain conjugated polyene structure and release HCl:\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"315\" height=\"38\"\u003e\u003c/p\u003e \u003cp\u003eAnd as the de-HCl reaction continues, the generated HCl acts as a catalyst to promote the continuous dechlorination reaction, the reaction rate of which rises with the increase of HCl concentration. At this time, the length (n) of the double bond in the conjugated polyene structure gradually increases and is thus extended into a conjugated polyene sequence:\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"467\" height=\"41\"\u003e\u003c/p\u003e \u003cp\u003eEventually, as the PVC decomposition reaction continues, the conjugated polyene structure undergoes cyclization, cross-linking and other reactions to generate polycyclic aromatic hydrocarbons (PAHs), accompanied by the generation of carbons:\u003c/p\u003e \u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"330\" height=\"102\"\u003e\u003c/p\u003e \u003cp\u003eIn the above study, when the hot pressing temperature is low, the overall color of the CGF/PVC laminates surface shows a relatively uniform white color, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, indicating that the PVC resin has not yet produced significant thermal decomposition phenomenon at this time. When the hot pressing temperature rises to 180 ℃, CGF/PVC laminates begin to show slight yellowing in local areas, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec, which indicates that at this time, the PVC resin has begun to initially decompose and accompanied by the release of a trace amount of HCl, and at the same time triggered the formation of the conjugated polyene structure. However, at this time, due to the short length of the double bond in the conjugated chain formed, it only absorbs the ultraviolet light in the visible light, so the macroscopic color change of the surface of CGF/PVC laminates is not obvious yet. When the hot pressing temperature reaches 185 ℃, the color of CGF/PVC laminates further deepens and shows obvious yellow color, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed, indicating that the PVC resin has entered the stage of continuous dehydrogenation at this time, and the length of the double bond in the conjugated chain is further extended. Finally, when the hot pressing temperature is increased to 190 ℃, the yellow color of CGF/PVC laminates is expanded to the whole surface and further changed to orange-yellow color, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee. At this point, the overall mechanical properties of the prepared CGF/PVC laminates may have deteriorated to some extent due to degradation of the PVC resin.\u003c/p\u003e \u003cp\u003eTherefore, in order to verify the above conjecture, the mechanical properties of CGF/PVC laminates prepared with different hot pressing temperatures are further investigated. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the influence of different hot pressing temperatures on the mechanical properties of the prepared CGF/PVC laminates, from which it can be seen that, with the increasing hot pressing temperature, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the CGF/PVC laminates show a tendency of increasing and then decreasing, and all of them reach a great value when the hot pressing temperature is 180 ℃, with the values of 212.16 MPa, 196.12 MPa, 20.53 MPa and 145.45 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the hot pressing temperature 170\u0026thinsp;~\u0026thinsp;180 ℃ range of this interval, has been cured PVC resin will begin to soften again, and with the increasing temperature and gradually reach a better molten state, in the joint action of the pressure to achieve the second infiltration of the fiber. At this time, the physical occlusion between the fiber and the resin matrix will be further strengthened, which can effectively improve the load transfer efficiency, so that the overall mechanical properties of the material to a greater extent. When the hot pressing temperature exceeds 180 ℃, the PVC resin gradually begins to decompose, and as the temperature continues to rise, the de-HCl reaction continues to intensify, which leads to the accumulation of conjugated polyene structures. These accumulated conjugated polyene structures not only weaken the toughness of the resin matrix, but also form stress concentration points at the fiber-resin matrix interface. Ultimately, the tensile strength, flexural strength, interlaminar shear strength, and notched impact toughness of the prepared CGF/PVC laminates are reduced by 6.7%, 5.7%, 10.4%, and 7.0%, respectively, compared with the optimal values when the hot pressing temperature reached 190 ℃.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Hot pressing pressure analysis\u003c/h2\u003e \u003cp\u003eAs another important process parameter of compression molding, the size of the hot pressing pressure also has an important influence on the properties of the prepared CGF/PVC laminates. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the influence of different hot pressing pressure on the mechanical properties of the prepared CGF/PVC laminates, at which the hot pressing temperature and hot pressing time are fixed at 180 ℃ and 6 min, respectively. It can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e that with the increasing of hot pressing pressure in a certain range (4\u0026thinsp;~\u0026thinsp;7 MPa), the mechanical properties of CGF/PVC laminates maintain a continuous elevation trend. When the hot pressing pressure reaches 7 MPa, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the CGF/PVC laminates prepared at this time are 236.52 MPa, 229.39 MPa, 23.06 MPa and 167.13 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively, which increase 11.5%, 17.0%, 12.3% and 14.9%, respectively, compared with the mechanical properties of the CGF/PVC laminates corresponding to the CGF/PVC laminates prepared with a hot pressing pressure of 4 MPa. When the hot pressing pressure is further increased to 8 MPa, the mechanical properties of CGF/PVC laminates prepared at this time began to show a decreasing trend.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAt a lower hot pressing pressure (4 MPa), although some of the fibers in the prepared CGF/PVC laminates have achieved a preliminary bonding with the PVC resin matrix, some tiny voids still existed in the laminated layers due to the limited pressure. At this time, the PVC resin does not achieve a good infiltration effect on the fiber, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea. With the increasing pressure of hot pressing (5\u0026thinsp;~\u0026thinsp;7 MPa), a closer interfacial bond between PVC resin matrix and fiber is gradually formed, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb, Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec and Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed. At this time, the tiny gaps existing between the layers of CGF/PVC laminates are effectively compressed and discharged, and the interfacial defects are reduced significantly, which enhances the overall mechanical properties of the material to a certain extent. However, when the hot pressing pressure reaches 8 MPa, the PVC resin is over-extruded at this pressure value, which results in uneven distribution of the resin matrix and insufficient impregnation in localized areas of the interface, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ee, which ultimately affects the overall mechanical properties of the material.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn addition, it is found that the surface quality of CGF/PVC laminates gradually shows a better level with the increasing of the hot pressing pressure by observing the surface microscopic morphology of CGF/PVC laminates prepared under different hot pressing pressures and determining the surface roughness value. When the hot pressing pressure is only 4 MPa, due to the high viscosity of the PVC melt, it is not possible to achieve effective flow under this pressure, resulting in poor secondary impregnation of the fiber to the extent that obvious microscopic defects appear on the surface of the material, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea, and the surface roughness as a whole is also at a high value, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea. With the hot pressing pressure increased to 5 MPa, this time the material surface quality has been improved to some extent, but a variety of microscopic defects are still more obvious, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb, corresponding to the surface roughness still has a large value, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb. When the hot pressing pressure continues to increase to 6 MPa, the material surface has no obvious microscopic defects, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec, but the surface flatness is still to be further improved, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ec. Eventually, when the hot pressing pressure is further increased to 7 MPa and 8 MPa, the surface of the material is smooth and flat at this time, and a few fiber rows can be observed, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ed and Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ee, and the corresponding maximum values of the surface roughness are kept at a level of less than 100 nm, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ed and Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ee. However, when the hot pressing pressure is 8 MPa, the number of fibers on the surface of the material can be observed to increase, and it can be clearly observed that the fibers appear to be irregularly arranged, and this phenomenon will lead to the material force, the stress is not uniformly transmitted in the interior of the material, which will have a certain negative impact on the overall mechanical properties of the material.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Hot pressing time analysis\u003c/h2\u003e \u003cp\u003eIn the compression molding process, hot pressing temperature, hot pressing pressure and hot pressing time work together to determine the final properties of the material. Only when the hot pressing temperature is sufficient to melt the resin matrix, the hot pressing pressure can realize good compaction and the hot pressing time is set reasonably, the final material properties can be optimized. Therefore, in this subsection, based on the optimal hot pressing temperature of 180 ℃ and hot pressing pressure of 7 MPa determined above, an in-depth investigation of the hot pressing time is carried out, so as to achieve the purpose of continuous optimization of the properties of the prepared CGF/PVC laminates.\u003c/p\u003e \u003cp\u003eThe effects of different hot pressing times on the mechanical properties of the prepared CGF/PVC laminates are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. As can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, when the hot pressing time is increasing in the range of 6\u0026thinsp;~\u0026thinsp;12 min, the mechanical properties of the material show a continuous increasing trend. Finally, when the hot pressing time is 12 min, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the material reach a great value of 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively, which increase 6.8%, 7.6%, 10.1% and 5.0%, respectively, compared to the mechanical properties of the CGF/PVC laminates prepared with a hot pressing time of 6 min. After the hot pressing time exceeds 12 min, the mechanical properties of the material begin to decrease continuously. Finally, when the hot pressing time increases to 18 min, the mechanical properties of the CGF/PVC laminates prepared at this time decrease to 241.27 MPa, 233.41 MPa, 23.92 MPa, and 169.78 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively. Compared with their optimal mechanical properties, the degree of decrease is 4.5%, 5.4%, 5.8%, and 4.0%, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSince PVC is a thermoplastic resin, its melting behavior is governed by a combination of temperature and time. At the beginning of the hot pressing stage, PVC resin needs to absorb enough heat to overcome the glass transition temperature (Tg\u0026thinsp;=\u0026thinsp;81.6\u0026deg;C) and enter the viscoelastic state. If the hot pressing time is too short, the resin does not melt sufficiently and the viscosity is too high, which makes it difficult to effectively infiltrate the fiber, thus leading to poor overall mechanical properties of the material. With the increasing hot pressing time, the PVC resin matrix has more time to fully melt and flow under the high temperature and high pressure environment, so that it can better infiltrate the fiber and form a good interfacial bond with the fiber, which makes the overall mechanical properties of the material continue to improve. However, when the hot pressing time exceeds a certain threshold, while further extension of the time allows for continuous compaction of the material under high temperature and high pressure conditions, it also poses the risk of localized overheating or degradation, which can lead to adverse effects on the properties of the final prepared material.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Comparison of GF/PVC composites properties\u003c/h2\u003e \u003cp\u003eIt is found through the above study that controlling the temperature, pressure and time of the hot pressing stage at 180 ℃, 7 MPa and 12 min, respectively, during the compression molding process for the preparation of SG-8 CGF/PVC laminates is an optimal process condition, at which time the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of the prepared composites are 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m\u003csup\u003e2\u003c/sup\u003e, which is a high level compared with domestic and international studies. Compared to the fiber-less reinforced PVC sheets prepared under the same experimental, process, and additive conditions, the corresponding mechanical properties (59.21 MPa, 76.63 MPa, 6.89 MPa, and 87.71 kJ/m\u003csup\u003e2\u003c/sup\u003e) are improved by 326.7%, 222.0%, 268.4% and 101.6%, respectively. Comparison of this study with typical domestic and international studies on the properties of GF/PVC composites is shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\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\u003eComparison of properties of GF/PVC composites\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAuthor\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTensile strength (MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFlexural strength (MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eInterlaminar shear strength (MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eImpact toughness (kJ/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePark et al.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e328.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e93.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWang et al.\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e345\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e302\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e199\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKhan et al.\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLee et al.\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e330\u0026thinsp;~\u0026thinsp;340\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95\u0026thinsp;~\u0026thinsp;100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u0026thinsp;~\u0026thinsp;8.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWang et al.\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNguyen et al.\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e229\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThe study\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e252.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e246.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e176.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eIn this paper, the preparation of CGF/PVC laminates are accomplished by compression molding process, in which the effects of three parameters, namely, temperature, pressure and time, on the properties of CGF/PVC laminates at the stage of hot pressing are analyzed, and the mechanism of thermal decomposition of PVC is also elaborated in detail, and the main conclusions of the study are as follows:\u003c/p\u003e \u003cp\u003eWhen the hot pressing temperature, hot pressing pressure and hot pressing time are controlled to be 180 ℃, 7 MPa and 12 min, respectively, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of CGF/PVC laminates prepared at this time have an optimum value of 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively. Compared to the fiber-less reinforced PVC sheets prepared under the same experimental, process and additive conditions, the corresponding mechanical properties are improved by 326.7%, 222.0%, 268.4% and 101.6%, respectively.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of Interest\u003c/h2\u003e \u003cp\u003eThe authors declare no competing financial interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contributions\u003c/h2\u003e \u003cp\u003e \u003cb\u003eZetian Hua\u003c/b\u003e: Writing \u0026ndash; original draft (lead); investigation (lead). \u003cb\u003eRun Zhang\u003c/b\u003e: Supervision (lead); writing \u0026ndash; review and editing (lead). \u003cb\u003eChenchao Fu\u003c/b\u003e: Supervision (equal). \u003cb\u003eLin Jiang\u003c/b\u003e: writing \u0026ndash; review and editing (equal). \u003cb\u003eMingfei Liu\u003c/b\u003e: writing \u0026ndash; review and editing (equal). \u003cb\u003ePing Xue\u003c/b\u003e: Resources (lead); supervision (equal).\u003c/p\u003e\u003ch2\u003eAcknowledgment\u003c/h2\u003e \u003cp\u003eThe authors would like to acknowledge the support of the Analysis and Test Center of Beijing University of Chemical Technology.\u003c/p\u003e\u003ch2\u003eData Availability Statement\u003c/h2\u003e \u003cp\u003eData available on request from the authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePan Y T, Yuan Y, Wang D Y, et al. 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Polym Compos. 1987, 8(5): 298\u0026ndash;307.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"CGF/PVC, compression molding, surface quality, mechanical properties, microscopic morphology","lastPublishedDoi":"10.21203/rs.3.rs-6598139/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6598139/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this paper, CGF/PVC composite prepreg is prepared by dry powder impregnation process, and then, on this basis, the preparation of CGF/PVC laminates are further accomplished by compression molding. The optimum hot pressing process conditions for the preparation of CGF/PVC laminates by compression molding are determined through the continuous optimization of parameters such as temperature, pressure and time at the hot pressing stage by the one-factor-variable method. When the hot pressing temperature, hot pressing pressure and hot pressing time are 180 ℃, 7 MPa and 12 min, respectively, the tensile strength, flexural strength, interlaminar shear strength and notched impact toughness of CGF/PVC laminates prepared at this time are 252.65 MPa, 246.73 MPa, 25.38 MPa and 176.79 kJ/m\u003csup\u003e2\u003c/sup\u003e, respectively. This study not only provides a process optimization strategy for the preparation of CGF/PVC composites by compression molding, but also further provides important theoretical and practical guidance for the industrial production of high-performance CGF/PVC composites.\u003c/p\u003e","manuscriptTitle":"Preparation of high-performance CGF/PVC laminates: optimization of compression molding process parameters","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-20 06:12:59","doi":"10.21203/rs.3.rs-6598139/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-05-16T01:47:52+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-16T01:09:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Journal of Polymer Research","date":"2025-05-09T15:17:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-07T02:50:33+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Polymer Research","date":"2025-05-06T06:34:44+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"b98d016e-962f-4ffc-88ef-f07660572cc9","owner":[],"postedDate":"May 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-08-18T16:08:23+00:00","versionOfRecord":{"articleIdentity":"rs-6598139","link":"https://doi.org/10.1007/s10965-025-04509-7","journal":{"identity":"journal-of-polymer-research","isVorOnly":false,"title":"Journal of Polymer Research"},"publishedOn":"2025-08-11 15:58:09","publishedOnDateReadable":"August 11th, 2025"},"versionCreatedAt":"2025-05-20 06:12:59","video":"","vorDoi":"10.1007/s10965-025-04509-7","vorDoiUrl":"https://doi.org/10.1007/s10965-025-04509-7","workflowStages":[]},"version":"v1","identity":"rs-6598139","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6598139","identity":"rs-6598139","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}