Investigation into the effects of varying percent concentrations of ethyl acetate on the rate of dissolving polylactic acid

Investigation into the effects of varying percent concentrations of ethyl acetate on the rate of dissolving polylactic acid | 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 Investigation into the effects of varying percent concentrations of ethyl acetate on the rate of dissolving polylactic acid Finian George Knepper This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7335944/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 3-D printing is the process of turning a computer-generated model into a physical object. 3-D printers melt polymers. Mechanical nozzles extrude this melted polymer layer-by-layer from the base to create physical models. This has many applications in medicine; doctors use 3-D printed parts to create accurate medical devices to match each patient's unique anatomy, for example. Due to 3-D printing’s vertical method, a 3D printer must print out additional supports to hold up models during their fabrication. A common material for the creation of these supports is Poly-Lactic Acid (PLA). Once the model is fabricated, these supports must be removed. This is done by hand with a pair of clippers. When models are delicate and complex, this process can be damaging. Thus, a way to remove these supports without damaging the models is needed. On an industrial scale, ethyl acetate at 100% concentrations is used to dissolve PLA. Ethyl Acetate is incredibly flammable, vaporous, and combustible. 100% concentrations of it are too dangerous to use in uncontrolled environments. It is necessary to find lower percentage concentrations that are safer, yet still effective at dissolving PLA. This paper examined the effectiveness of varying percent concentrations of ethyl acetate on polylactic acid. Polymers Poly-lactic acid PLA Ethyl Acetate dissolving percent concentrations Figures Figure 1 1. Literature review 1.1. Properties of poly-lactic acid Polylactic acid is a biodegradable thermoplastic. While it is called polylactic acid, it is in fact polyester. This means its repeating molecule Lactic acid (C₃H₆O₃) is joined together by ester linkages with the formula -COO-. 1.2. Properties of ethyl acetate Ethyl acetate is another ester, with the monomer C₄H₈O₂. Its monomers are connected by ester linkages with -COO- bonds, each hydrogen atom connected between each. It is commonly used as a solvent in the 3-D printing industry; but it is incredibly flammable and combustible. 1.3. The reaction of ethyl acetate and poly-lactic acid When polylactic acid and ethyl acetate react, they react in an ester exchange reaction. During this reaction type, the alkoxy groups are exchanged. In the reaction of PLA and ethyl acetate, the monomer of ethyl acetate swaps with the ester bond between the monomers of PLA, and forms ethyl lactate. This reaction only goes to completion at higher temperatures, as it provides the required energy to break the chemical bonds and complete the reaction. It is hypothesized that when PLA and ethyl acetate react, ethyl lactate will form, and will break off from the PLA, leading to it dissolving. The reaction formula for this process is: Polylactic Acid Ethyl Acetate Ethyl Lactate (C3H4O2)n + (CH₃COOCH₂CH₃) → (CH₃CH₂OCOCH₃) 2. Method 2.1. Research Question On an industrial scale, ethyl acetate, at 100% concentrations, is used to dissolve PLA. However, as discussed above, ethyl acetate is incredibly flammable, vaporous, and combustible. 100% concentrations of it are too dangerous to use in uncontrolled environments. It is necessary to find lower percent concentrations that are safer, yet still effective at dissolving PLA. This leads to the research question of this paper: What effect does varying percent ethyl acetate concentrations at 72 degrees Celsius on the rate of polylactic acid dissolving? 2.2. Materials ● 100 grams of clear Polylactic acid strands, 2mm diameter, commercial grade ● 500mL 1.0 molarity Ethyl Acetate ● 1 pair nitrile gloves ● 1 pair safety goggles ● 1 electronic balance, ± .001 grams margin of error ● 5 hot plates, capable of heating to 72 degrees Celsius and rotating a magnetic stirring bar at 90 rpms. ● 2 - 10mL graduated cylinders. ● 500mL distilled water. ● 5 - 500mL beakers ● 5 - 50 mL beakers ● 5 Celsius thermometers, ± .01 degree Celsius margin of error. ● 5 - 2cm long magnetic stir bars ● 1 stopwatch ● 1 pencil ● 1 sheet of paper ● 1 camera ● 1 pair of scissors ● 1 ruler ● 1 fume hood ● 2 eyedroppers. ● 1 funnel ● 1 pair tweezers ● 1 roll paper towels 2.3. Experiment Procedures 1. Measure and pour out 5 different 10 mL solutions of 100% distilled water, 0% ethyl acetate. Pour each of these into a 50 mL beaker. 2. Mass out 5 different .5-gram (± .001 gram) strands of clear polylactic acid. (A 17 cm strand is .5 grams.) 3. Weight and record the mass of these strands. 4. Coil up the strands by wrapping them around your index finger. This makes sure the PLA rests evenly at the bottom of the beaker and is fully submerged in the solutions. 5. Place the 5 PLA strands into 5 different 500mL beakers, along with a 2cm long magnetic stir bar in each beaker. 6. Place the 500mL beakers on the hotplates. 7. Pour 1 of the 50 mL beakers into one of the 500mL beakers. Repeat this for all 5 beakers. 8. Turn on the hotplates and set them all to 72 degrees Celsius. 9. Set the magnetic stir rod to stir at 90 rpm. 10. Immediately start the stopwatch. 11. Once 10 minutes have passed, use the tweezer to remove the PLA strands, place them on a paper towel. 12. Rinse the strands off with distilled water. 13. Air-dry the strands completely. 14. Weigh and record the mass of the PLA strands. 15. Repeat steps 1 through 14, 5 times, with 75% water – 25% ethyl acetate concentrations, 50% water - 50% ethyl acetate concentrations, 25% water - 75% ethyl acetate concentrations, and 0% water 100% ethyl acetate concentrations. By the end of the experiment, 5 trials for 5 different manipulations will happen. 2.4. Safety Procedures Polylactic Acid Safety Procedures: PLA is completely harmless. No procedures are needed. Disposal procedures: PLA will be thrown out in a trash can. Preparation procedures: PLA requires no procedures. Distilled Water: Safety Procedures: Distilled Water is completely harmless. No procedures are needed. Disposal procedures: Distilled water will be poured down a drain. Preparation procedures: Distilled water requires no preparation procedures. Ethyl acetate: Safety Procedures: Ethyl Acetate is listed as a hazardous substance by OSHA and other safety groups. This is due to it being: Flammable – Ethyl acetate will ignite if lit by fire. All contact or proximity to flames must be avoided. Toxic – Ethyl Acetate can irritate the eyes and skin. Nitrile gloves and safety goggles must be worn while handling. Vaporous – Ethyl Acetate produces vapors. These vapors are highly flammable and can cause dizziness, nausea, and fatigue. All operations with ethyl acetate must be done inside an active fume hood. Disposal procedures: Ethyl acetate cannot be poured down the drain or thrown out. All waste ethyl acetate will be poured into a volumetric flask with a rubber stopper, to keep vapors from escaping while it is stored. It will then be properly neutralized and disposed of by a trained chemical technician. Preparation procedures: Ethyl acetate must not have its container opened or be prepared until it is inside an active fume hood and whoever is using it is wearing nitrile gloves and safety goggles. Environmental Concerns: Polylactic acid – Polylactic acid poses no harm to the environment. Distilled Water – Distilled water poses no harm to the environment. Ethyl acetate – Ethyl acetate is toxic to the environment and will start a fire if improperly disposed of, which could devastate wildlife. All ethyl acetate must be properly handled and disposed of using the protocols explained above. 3. Ethical Considerations There are no ethical considerations. No living organisms will be harmed if safety protocols are followed. 4. Variables 4.1. Independent Variable The independent variable of this experiment is varying percent concentrations of ethyl acetate. This will be manipulated by measuring out % concentrations of ethyl acetate, out of 10ml. The concentrations that will be used are: -0% (Control) − 0mL ethyl acetate, 10mL water. -25% − 2.5mL ethyl acetate, 7.5mL water. -50% − 5mL ethyl acetate, 5mL water. -75% − 7.5mL ethyl acetate, 2.5mL water. -100%. − 10mL ethyl acetate, 0mL water. These values were chosen because 100% is what is used in an industrial setting, so it is the baseline for the efficacy of ethyl acetate on PLA. 0% is the control, and the other values are medians in between these values. These values will be measured in milliliters, using 10mL graduated cylinders. 4.2. Dependent Variable The dependent variable of this experiment is the rate of dissolving of Polylactic acid. The rate of dissolving is calculated by: ((original mass in grams) – (final mass in grams))/time (in minutes) The rate of dissolving was chosen because it effectively measures mass loss in proportion to time, as opposed to measuring mass loss on its own. To get original mass, .5 ± .001 grams of PLA will be measured on a scale. To get final mass, the same PLA strand will be measured on the same scale/ following the reaction. The time will be measured using a stopwatch. All PLA will be removed after 10 minutes. 4.3. Controlled Variables Temperature The reactions will be placed on hotplates. This is done to increase the temperature of the reaction and provide the required energy to complete the reaction. A thermometer will be placed inside each beaker to ensure they are all being heated to the same temperature, with an uncertainty of ± .01 degree Celsius. Volume of reactants The volume of the concentrations must be the same. They will all be 10 milliliters. This will be measured using a graduated cylinder with an uncertainty of ± .01mL. Initial Mass of Polylactic acid The initial mass of PLA must be the same across all trials. To ensure this, it will be massed to be .5 grams, using an electric balance with an uncertainty of ± .001 grams. Time of reaction All reactions will occur for 10 minutes before the PLA is removed. This will be measured using a stopwatch. This is to make sure that the reaction time is the same across all trials. Stirring All reactions will be stirred using a 2-centimeter-long magnetic stirring bar inside the reaction beakers, set to the same speed setting on the hotplate at 90 rotations per minute. This was done because ethyl acetate is insoluble in water, so the mixture must be stirred to keep them from separating. 5. Data 5.1. Narrated Data Processing In this experiment, the initial and final mass of polylactic acid was measured. From there, the rate of dissolving was calculated. The dependent variable of this experiment was the rate of dissolving, a scientific rate measured by (initial mass – final mass)/time (in minutes). This was first measured by massing the PLA before the reaction occurred, and then by massing the PLA after the reaction. This value was divided by how long the reaction was, in minutes. The rate of dissolving was chosen because it is the scientific standard for mass loss experiments of this type. 5 trials for each manipulation will be conducted for a greater quality of data. These values will be averaged for each manipulation. This is done to increase the accuracy of the experiment while considering all data. The values used for initial and final mass were the average of all 5 trials. This is done to achieve the most accurate result that considers all data. The average for initial mass was found by the equation: (trial 1 initial + trial 2 initial + trial 3 initial + trial 4 initial + trial 5 initial) / 5 The average for final mass was found by the equation: (trial 1 final + trial 2 final + trial 3 final + trial 4 final + trial 5 final) / 5 The propagated error is the mass of the electronic balance (± .001). This is the uncertainty for the measurements of initial and final mass. This value divided by the square root of the number of measurements (5) is the uncertainty for the average: ± .00045 The average initial mass - the average final mass is divided by the time of the reaction, in minutes (10). Thus, the rate of dissolving is: ((initial mass ± .00045) – (final mass ± .00045)) / 10. When two average uncertainties are subtracted, they are added in quadrature: sqrt (.00045^2 − .00045^2) = 0.000636 This value is then divided by time in minutes: (10) .000636/10 = ± .000064 The uncertainty for the rate of dissolving is ± .000064. A positive rate of dissolving means that mass has decreased, a negative rate means that mass has increased. A rate of 0 means the mass has not changed at all. The rate of dissolving is what is shown in the finalized data. 5.2. Raw Data 0% concentration ethyl acetate Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Average Initial mass (g) ± .00045 gram Rate of Dissolving 0.502 0.5 0.501 0.498 0.501 0.5 0 Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Average Final mass (g) ± .00045 gram 0.502 0.5 0.501 0.498 0.501 0.5 25% concentration ethyl acetate Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Average Initial mass (g) ± .00045 gram Rate of dissolving: 0.499 0.495 0.508 0.499 0.496 0.499 -0.0017 Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Average Final mass (g) ± .00045 gram 0.518 0.52 0.528 0.508 0.505 0.516 50% concentration ethyl acetate Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Average Initial mass (g) ± .00045 gram Rate of dissolving: 0.499 0.505 0.493 0.512 0.496 0.501 -0.0023 Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Average Final mass (g) ± .00045 gram 0.503 0.553 0.515 0.523 0.526 0.524 75% concentration ethyl acetate Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Average Initial mass (g) ± .00045 gram Rate of dissolving: 0.502 0.497 0.499 0.498 0.494 0.498 -0.0003 Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Average Final mass (g) ± .00045 gram 0.541 0.436 0.5 0.505 0.522 0.501 100% percent concentration ethyl acetate Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Initial mass (g) ± .001 gram Initial mass (g) Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Initial mass (g) ± .001 gram Average Initial mass (g) ± .00045 gram Rate of dissolving: 0.497 0.491 0.496 0.496 0.5 0.496 0.0069 Final mass (g) ± .001 gram Final mass (g) Final mass (g) ± .001 gram Final mass (g) ± .001 gram Final mass (g) ± .001 gram Average Final mass (g) ± .00045 gram 0.397 0.397 0.519 0.3 0.525 0.427 5.3. Processed Data 6. Conclusion Based on the results of the experiment, varying concentrations of ethyl acetate had the opposite predicted effect. Instead of decreasing the mass, in all cases except the 100% concentration trials the mass increased. This happened because of the lactic acid produced during the reaction. It was predicted that the lactic acid would form and then break off from the PLA. However, the lactic acid formed and then did not break off - leading to the mass increasing. In the 100% concentration - lactic acid formed to an extent to let it break off, leading to the mass decrease. The conclusion was that only 100% concentrations of ethyl acetate are effective at dissolving PLA. No other concentrations are effective. Declarations Author Contribution I, Finian Knepper, am the sole researcher of this paper. Experiments, data collection, research, and writing of the manuscript were all done by me. Acknowledgement I would like to acknowlege Jennifer Merriam, who generiously allowed me to use her lab and was a proctor during my experiments. Thank you, Mrs. Merriam. References Purdue University. Organic Chemistry . Purdue University Chemistry Department,https://chemed.chem.purdue.edu/genchem/topicreview/bp/3organic/organic.html. Accessed 10 Apr. 2025. Hubs. 3D Printing Guide . Hubs,https://www.hubs.com/guides/3d-printing/. Accessed 10 Apr. 2025. TWI Global. “What Is PLA?” TWI ,https://www.twi-global.com/technical-knowledge/faqs/what-is-pla. Accessed 10 Apr. 2025. National Center for Biotechnology Information. “Ethyl Acetate.” PubChem , U.S. National Library of Medicine,https://pubchem.ncbi.nlm.nih.gov/compound/Ethyl-Acetate. Accessed 10 Apr. 2025. Smith, James. “Transesterification.” Master Organic Chemistry , 10 Nov. 2022,https://www.masterorganicchemistry.com/2022/11/10/transesterification/. Accessed 10 Apr. 2025. CK-12 Foundation. “Rate of Dissolving.” LibreTexts Chemistry ,https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/16%3A_Solutions/16.02%3A_Rate_of_Dissolving. Accessed 10 Apr. 2025. New Jersey Department of Health. Hazardous Substance Fact Sheet: Ethyl Acetate .https://www.nj.gov/health/eoh/rtkweb/documents/fs/0841.pdf. Accessed 10 Apr. 2025. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7335944","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":500360533,"identity":"c1a0801c-19e4-4007-86d9-a5847e2a85f4","order_by":0,"name":"Finian George Knepper","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBElEQVRIiWNgGAWjYBAC9mYGhgNA2gDKtwFixsYD+LTwHEbVkgbS0oBfC1QWpuUwmMSvhZ334IGfOxiMzdl7jz34uOe83dr2w0BbamyicWph5ks42HuGwcyy51y64Yxnt5O3nUkEajmWltuAQ4s9M4/BAd42BhuDGzlm0jwHbiebHQBqYWw4jFMLD1DLwb8gLfffmEn/OXAu2ez8Q8JaDgNtMTO4wWMmzXDggJ3ZDSJsOSzbJmFscCYv3bDnQHKC2Q2gLQl4/MLDf8b449s2G8MNx88ee/DjgJ292fn0hw8+1Njg1AIFEiDdbCBWIlhlAn7lcAvBWuyJUzwKRsEoGAUjCQAAkgBh3qvSs8sAAAAASUVORK5CYII=","orcid":"","institution":"Cheyenne East High School","correspondingAuthor":true,"prefix":"","firstName":"Finian","middleName":"George","lastName":"Knepper","suffix":""}],"badges":[],"createdAt":"2025-08-09 21:23:12","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7335944/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7335944/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":89388806,"identity":"53624012-f18b-404f-8511-ccab7717c71e","added_by":"auto","created_at":"2025-08-19 12:43:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":36337,"visible":true,"origin":"","legend":"\u003cp\u003eUnnumbered image in the Data section.\u003c/p\u003e","description":"","filename":"Uf1.png","url":"https://assets-eu.researchsquare.com/files/rs-7335944/v1/1848b6c4698a468f07c6727f.png"},{"id":92027615,"identity":"866792e3-6ca0-446b-b8e6-3b149e1e3593","added_by":"auto","created_at":"2025-09-23 19:23:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1009823,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7335944/v1/134b4a52-ff72-4071-bd82-e131d91747f4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation into the effects of varying percent concentrations of ethyl acetate on the rate of dissolving polylactic acid","fulltext":[{"header":"1. Literature review","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003e1.1. Properties of poly-lactic acid\u003c/h2\u003e\u003cp\u003ePolylactic acid is a biodegradable thermoplastic. While it is called polylactic acid, it is in fact polyester. This means its repeating molecule Lactic acid (C₃H₆O₃) is joined together by ester linkages with the formula -COO-.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e1.2. Properties of ethyl acetate\u003c/h2\u003e\u003cp\u003eEthyl acetate is another ester, with the monomer C₄H₈O₂. Its monomers are connected by ester linkages with -COO- bonds, each hydrogen atom connected between each. It is commonly used as a solvent in the 3-D printing industry; but it is incredibly flammable and combustible.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e1.3. The reaction of ethyl acetate and poly-lactic acid\u003c/h2\u003e\u003cp\u003eWhen polylactic acid and ethyl acetate react, they react in an ester exchange reaction. During this reaction type, the alkoxy groups are exchanged. In the reaction of PLA and ethyl acetate, the monomer of ethyl acetate swaps with the ester bond between the monomers of PLA, and forms ethyl lactate. This reaction only goes to completion at higher temperatures, as it provides the required energy to break the chemical bonds and complete the reaction. It is hypothesized that when PLA and ethyl acetate react, ethyl lactate will form, and will break off from the PLA, leading to it dissolving. The reaction formula for this process is:\u003c/p\u003e\u003cp\u003ePolylactic Acid Ethyl Acetate Ethyl Lactate\u003c/p\u003e\u003cp\u003e(C3H4O2)n + (CH₃COOCH₂CH₃) \u0026rarr; (CH₃CH₂OCOCH₃)\u003c/p\u003e\u003c/div\u003e"},{"header":"2. Method","content":"\u003ch2\u003e2.1. Research Question\u003c/h2\u003e\n\u003cp\u003eOn an industrial scale, ethyl acetate, at 100% concentrations, is used to dissolve PLA. However, as discussed above, ethyl acetate is incredibly flammable, vaporous, and combustible. 100% concentrations of it are too dangerous to use in uncontrolled environments. It is necessary to find lower percent concentrations that are safer, yet still effective at dissolving PLA. This leads to the research question of this paper:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat effect does varying percent ethyl acetate concentrations at 72 degrees Celsius on the rate of polylactic acid dissolving?\u003c/strong\u003e\u003c/p\u003e\n\u003ch2\u003e2.2. Materials\u003c/h2\u003e\n\u003cp\u003e● 100 grams of clear Polylactic acid strands, 2mm diameter, commercial grade\u003c/p\u003e\n\u003cp\u003e● 500mL 1.0 molarity Ethyl Acetate\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 pair nitrile gloves\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 pair safety goggles \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 electronic balance, \u0026plusmn; .001 grams margin of error\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 5 hot plates, capable of heating to 72 degrees Celsius and rotating a magnetic stirring bar at 90 rpms.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 2 - 10mL graduated cylinders. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 500mL distilled water.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 5 - 500mL beakers\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 5 - 50 mL beakers\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 5 Celsius thermometers, \u0026plusmn; .01 degree Celsius margin of error.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 5 - 2cm long magnetic stir bars\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 stopwatch\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 pencil\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 sheet of paper\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 camera\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 pair of scissors\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 ruler\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 fume hood\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 2 eyedroppers.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 funnel\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 pair tweezers\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● 1 roll paper towels\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Experiment Procedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1. \u0026nbsp; Measure and pour out 5 different 10 mL solutions of 100% distilled water, 0% ethyl acetate. Pour each of these into a 50 mL beaker.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. \u0026nbsp; Mass out 5 different .5-gram (\u0026plusmn; .001 gram) strands of clear polylactic acid. (A 17 cm strand is .5 grams.) \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3. \u0026nbsp; Weight and record the mass of these strands. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4. \u0026nbsp; Coil up the strands by wrapping them around your index finger. This makes sure the PLA rests evenly at the bottom of the beaker and is fully submerged in the solutions. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e5. \u0026nbsp; Place the 5 PLA strands into 5 different 500mL beakers, along with a 2cm long magnetic stir bar in each beaker. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e6. \u0026nbsp; Place the 500mL beakers on the hotplates.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e7. \u0026nbsp; Pour 1 of the 50 mL beakers into one of the 500mL beakers. Repeat this for all 5 beakers. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e8. \u0026nbsp; Turn on the hotplates and set them all to 72 degrees Celsius. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e9. \u0026nbsp; Set the magnetic stir rod to stir at 90 rpm. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e10. \u0026nbsp;Immediately start the stopwatch.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e11. \u0026nbsp;Once 10 minutes have passed, use the tweezer to remove the PLA strands, place them on a paper towel. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e12. \u0026nbsp;Rinse the strands off with distilled water. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e13. \u0026nbsp;Air-dry the strands completely. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e14. Weigh and record the mass of the PLA strands.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e15. \u0026nbsp;Repeat steps 1 through 14, 5 times, with 75% water \u0026ndash; 25% ethyl acetate concentrations, 50% water - 50% ethyl acetate concentrations, 25% water - 75% ethyl acetate concentrations, and 0% water 100% ethyl acetate concentrations.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBy the end of the experiment, 5 trials for 5 different manipulations will happen.\u003c/p\u003e\n\u003ch2\u003e2.4. Safety Procedures\u003c/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePolylactic Acid\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSafety Procedures:\u003c/strong\u003e PLA is completely harmless. No procedures are needed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisposal procedures:\u003c/strong\u003e PLA will be thrown out in a trash can. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation procedures:\u0026nbsp;\u003c/strong\u003ePLA requires no procedures.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDistilled Water:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSafety Procedures:\u0026nbsp;\u003c/strong\u003eDistilled Water is completely harmless. No procedures are needed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisposal procedures:\u003c/strong\u003e Distilled water will be poured down a drain. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation procedures:\u003c/strong\u003e Distilled water requires no preparation procedures.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthyl acetate:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSafety Procedures:\u003c/strong\u003e Ethyl Acetate is listed as a hazardous substance by OSHA and other safety groups. This is due to it being:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFlammable \u0026ndash; Ethyl acetate will ignite if lit by fire. All contact or proximity to \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; flames must be avoided. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eToxic \u0026ndash; Ethyl Acetate can irritate the eyes and skin. Nitrile gloves and safety \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; goggles must be worn while handling. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eVaporous \u0026ndash; Ethyl Acetate produces vapors. These vapors are highly \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; flammable and can cause dizziness, nausea, and fatigue. All operations with ethyl acetate must be done inside an active fume hood.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisposal procedures:\u0026nbsp;\u003c/strong\u003eEthyl acetate cannot be poured down the drain or thrown out. All waste ethyl acetate will be poured into a volumetric flask with a rubber stopper, to keep vapors from escaping while it is stored. It will then be properly neutralized and disposed of by a trained chemical technician. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation procedures:\u003c/strong\u003e Ethyl acetate must not have its container opened or be prepared until it is inside an active fume hood and whoever is using it is wearing nitrile gloves and safety goggles. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEnvironmental Concerns:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePolylactic acid \u0026ndash; Polylactic acid poses no harm to the environment. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDistilled Water \u0026ndash; Distilled water poses no harm to the environment. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEthyl acetate \u0026ndash; Ethyl acetate is toxic to the environment and will start a fire if \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; improperly disposed of, which could devastate wildlife. All ethyl acetate must be \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; properly handled and disposed of using the protocols explained above.\u0026nbsp;\u003c/p\u003e"},{"header":"3. Ethical Considerations","content":"\u003cp\u003eThere are no ethical considerations. No living organisms will be harmed if safety protocols are followed.\u003c/p\u003e"},{"header":"4. Variables","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n \u003ch2\u003e4.1. Independent Variable\u003c/h2\u003e\n \u003cp\u003e\u003cstrong\u003eThe independent variable of this experiment is varying percent concentrations of ethyl acetate.\u003c/strong\u003e This will be manipulated by measuring out % concentrations of ethyl acetate, out of 10ml. The concentrations that will be used are:\u003c/p\u003e\n \u003cp\u003e-0% (Control) \u0026minus;\u0026thinsp;0mL ethyl acetate, 10mL water.\u003c/p\u003e\n \u003cp\u003e-25% \u0026minus;\u0026thinsp;2.5mL ethyl acetate, 7.5mL water.\u003c/p\u003e\n \u003cp\u003e-50% \u0026minus;\u0026thinsp;5mL ethyl acetate, 5mL water.\u003c/p\u003e\n \u003cp\u003e-75% \u0026minus;\u0026thinsp;7.5mL ethyl acetate, 2.5mL water.\u003c/p\u003e\n \u003cp\u003e-100%. \u0026minus;\u0026thinsp;10mL ethyl acetate, 0mL water.\u003c/p\u003e\n \u003cp\u003eThese values were chosen because 100% is what is used in an industrial setting, so it is the baseline for the efficacy of ethyl acetate on PLA. 0% is the control, and the other values are medians in between these values. These values will be measured in milliliters, using 10mL graduated cylinders.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\n \u003ch2\u003e4.2. Dependent Variable\u003c/h2\u003e\n \u003cp\u003e\u003cstrong\u003eThe dependent variable of this experiment is the rate of dissolving of Polylactic acid.\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe rate of dissolving is calculated by:\u003c/p\u003e\n \u003cp\u003e((original mass in grams) \u0026ndash; (final mass in grams))/time (in minutes)\u003c/p\u003e\n \u003cp\u003eThe rate of dissolving was chosen because it effectively measures mass loss in proportion to time, as opposed to measuring mass loss on its own.\u003c/p\u003e\n \u003cp\u003eTo get original mass, .5\u0026thinsp;\u0026plusmn;\u0026thinsp;.001 grams of PLA will be measured on a scale.\u003c/p\u003e\n \u003cp\u003eTo get final mass, the same PLA strand will be measured on the same scale/ following the reaction.\u003c/p\u003e\n \u003cp\u003eThe time will be measured using a stopwatch. All PLA will be removed after 10 minutes.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\n \u003ch2\u003e4.3. Controlled Variables\u003c/h2\u003e\n \u003cp\u003e\u003cstrong\u003eTemperature\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe reactions will be placed on hotplates. This is done to increase the temperature of the reaction and provide the required energy to complete the reaction. A thermometer will be placed inside each beaker to ensure they are all being heated to the same temperature, with an uncertainty of \u0026plusmn;\u0026thinsp;.01 degree Celsius.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eVolume of reactants\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe volume of the concentrations must be the same. They will all be 10 milliliters. This will be measured using a graduated cylinder with an uncertainty of \u0026plusmn;\u0026thinsp;.01mL.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eInitial Mass of Polylactic acid\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe initial mass of PLA must be the same across all trials. To ensure this, it will be massed to be .5 grams, using an electric balance with an uncertainty of \u0026plusmn;\u0026thinsp;.001 grams.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eTime of reaction\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAll reactions will occur for 10 minutes before the PLA is removed. This will be measured using a stopwatch. This is to make sure that the reaction time is the same across all trials.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eStirring\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAll reactions will be stirred using a 2-centimeter-long magnetic stirring bar inside the reaction beakers, set to the same speed setting on the hotplate at 90 rotations per minute. This was done because ethyl acetate is insoluble in water, so the mixture must be stirred to keep them from separating.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"5. Data","content":"\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e5.1. Narrated Data Processing\u003c/h2\u003e\u003cp\u003eIn this experiment, the initial and final mass of polylactic acid was measured. From there, the rate of dissolving was calculated. The dependent variable of this experiment was the rate of dissolving, a scientific rate measured by (initial mass \u0026ndash; final mass)/time (in minutes). This was first measured by massing the PLA before the reaction occurred, and then by massing the PLA after the reaction. This value was divided by how long the reaction was, in minutes. The rate of dissolving was chosen because it is the scientific standard for mass loss experiments of this type. 5 trials for each manipulation will be conducted for a greater quality of data. These values will be averaged for each manipulation. This is done to increase the accuracy of the experiment while considering all data. The values used for initial and final mass were the average of all 5 trials. This is done to achieve the most accurate result that considers all data.\u003c/p\u003e\u003cp\u003eThe average for initial mass was found by the equation:\u003c/p\u003e\u003cp\u003e(trial 1 initial\u0026thinsp;+\u0026thinsp;trial 2 initial\u0026thinsp;+\u0026thinsp;trial 3 initial\u0026thinsp;+\u0026thinsp;trial 4 initial\u0026thinsp;+\u0026thinsp;trial 5 initial) / 5\u003c/p\u003e\u003cp\u003eThe average for final mass was found by the equation:\u003c/p\u003e\u003cp\u003e(trial 1 final\u0026thinsp;+\u0026thinsp;trial 2 final\u0026thinsp;+\u0026thinsp;trial 3 final\u0026thinsp;+\u0026thinsp;trial 4 final\u0026thinsp;+\u0026thinsp;trial 5 final) / 5\u003c/p\u003e\u003cp\u003eThe propagated error is the mass of the electronic balance (\u0026plusmn;\u0026thinsp;.001). This is the uncertainty for the measurements of initial and final mass. This value divided by the square root of the number of measurements (5) is the uncertainty for the average: \u0026plusmn; .00045\u003c/p\u003e\u003cp\u003eThe average initial mass - the average final mass is divided by the time of the reaction, in minutes (10). Thus, the rate of dissolving is:\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e((initial mass\u0026thinsp;\u0026plusmn;\u0026thinsp;.00045) \u0026ndash; (final mass\u0026thinsp;\u0026plusmn;\u0026thinsp;.00045)) / 10.\u003c/p\u003e\u003cp\u003eWhen two average uncertainties are subtracted, they are added in quadrature:\u003c/p\u003e\u003cp\u003esqrt (.00045^2 \u0026minus;\u0026thinsp;.00045^2)\u0026thinsp;=\u0026thinsp;0.000636\u003c/p\u003e\u003cp\u003eThis value is then divided by time in minutes: (10)\u003c/p\u003e\u003cp\u003e.000636/10\u0026thinsp;=\u0026thinsp;\u0026plusmn;\u0026thinsp;.000064\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe uncertainty for the rate of dissolving is \u0026plusmn;\u0026thinsp;.000064.\u003c/p\u003e\u003cp\u003eA positive rate of dissolving means that mass has decreased, a negative rate means that mass has increased. A rate of 0 means the mass has not changed at all. The rate of dissolving is what is shown in the finalized data.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e5.2. Raw Data\u003c/h2\u003e\u003cp\u003e0% concentration ethyl acetate\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTrial 1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrial 2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTrial 3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTrial 4\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrial 5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInitial mass (g)\u0026thinsp;\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInitial mass (g)\u0026thinsp;\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInitial mass (g)\u0026thinsp;\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Initial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRate of Dissolving\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.502\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Final mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.502\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003e25% concentration ethyl acetate\u003c/h3\u003e\n\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTrial 1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrial 2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTrial 3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTrial 4\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrial 5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Initial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRate of dissolving:\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.495\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.508\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-0.0017\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Final mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.518\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.528\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.508\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.505\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.516\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003e50% concentration ethyl acetate\u003c/h3\u003e\n\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabc\" border=\"1\"\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTrial 1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrial 2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTrial 3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTrial 4\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrial 5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Initial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRate of dissolving:\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.505\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.493\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.512\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-0.0023\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Final mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.503\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.553\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.515\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.523\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.526\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.524\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003e75% concentration ethyl acetate\u003c/h3\u003e\n\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabd\" border=\"1\"\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTrial 1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrial 2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTrial 3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTrial 4\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrial 5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Initial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRate of dissolving:\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.502\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.497\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.494\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-0.0003\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Final mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.541\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.436\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.505\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.522\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.501\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003e100% percent concentration ethyl acetate\u003c/h3\u003e\n\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabe\" border=\"1\"\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTrial 1\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTrial 2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTrial 3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTrial 4\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTrial 5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInitial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Initial mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRate of dissolving:\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.497\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.491\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.496\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.0069\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFinal mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.001 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eAverage Final mass (g)\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;.00045 gram\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.397\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.397\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.519\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.525\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.427\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\u003ch2\u003e5.3. Processed Data\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"6. Conclusion","content":"\u003cp\u003eBased on the results of the experiment, varying concentrations of ethyl acetate had the opposite predicted effect. Instead of decreasing the mass, in all cases except the 100% concentration trials the mass increased. This happened because of the lactic acid produced during the reaction. It was predicted that the lactic acid would form and then break off from the PLA. However, the lactic acid formed and then did not break off - leading to the mass increasing. In the 100% concentration - lactic acid formed to an extent to let it break off, leading to the mass decrease. The conclusion was that only 100% concentrations of ethyl acetate are effective at dissolving PLA. No other concentrations are effective.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eI, Finian Knepper, am the sole researcher of this paper. Experiments, data collection, research, and writing of the manuscript were all done by me.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eI would like to acknowlege Jennifer Merriam, who generiously allowed me to use her lab and was a proctor during my experiments. Thank you, Mrs. Merriam.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePurdue University. \u003cem\u003eOrganic Chemistry\u003c/em\u003e. Purdue University Chemistry Department,https://chemed.chem.purdue.edu/genchem/topicreview/bp/3organic/organic.html. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eHubs. \u003cem\u003e3D Printing Guide\u003c/em\u003e. Hubs,https://www.hubs.com/guides/3d-printing/. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eTWI Global. \u0026ldquo;What Is PLA?\u0026rdquo; \u003cem\u003eTWI\u003c/em\u003e,https://www.twi-global.com/technical-knowledge/faqs/what-is-pla. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eNational Center for Biotechnology Information. \u0026ldquo;Ethyl Acetate.\u0026rdquo; \u003cem\u003ePubChem\u003c/em\u003e, U.S. National Library of Medicine,https://pubchem.ncbi.nlm.nih.gov/compound/Ethyl-Acetate. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eSmith, James. \u0026ldquo;Transesterification.\u0026rdquo; \u003cem\u003eMaster Organic Chemistry\u003c/em\u003e, 10 Nov. 2022,https://www.masterorganicchemistry.com/2022/11/10/transesterification/. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eCK-12 Foundation. \u0026ldquo;Rate of Dissolving.\u0026rdquo; \u003cem\u003eLibreTexts Chemistry\u003c/em\u003e,https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/16%3A_Solutions/16.02%3A_Rate_of_Dissolving. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003cli\u003eNew Jersey Department of Health. \u003cem\u003eHazardous Substance Fact Sheet: Ethyl Acetate\u003c/em\u003e.https://www.nj.gov/health/eoh/rtkweb/documents/fs/0841.pdf. Accessed 10 Apr. 2025. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"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":"Polymers, Poly-lactic acid, PLA, Ethyl Acetate, dissolving, percent concentrations","lastPublishedDoi":"10.21203/rs.3.rs-7335944/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7335944/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e3-D printing is the process of turning a computer-generated model into a physical object. 3-D printers melt polymers. Mechanical nozzles extrude this melted polymer layer-by-layer from the base to create physical models. This has many applications in medicine; doctors use 3-D printed parts to create accurate medical devices to match each patient's unique anatomy, for example.\u003c/p\u003e\u003cp\u003eDue to 3-D printing\u0026rsquo;s vertical method, a 3D printer must print out additional supports to hold up models during their fabrication. A common material for the creation of these supports is Poly-Lactic Acid (PLA). Once the model is fabricated, these supports must be removed. This is done by hand with a pair of clippers. When models are delicate and complex, this process can be damaging. Thus, a way to remove these supports without damaging the models is needed.\u003c/p\u003e\u003cp\u003eOn an industrial scale, ethyl acetate at 100% concentrations is used to dissolve PLA. Ethyl Acetate is incredibly flammable, vaporous, and combustible. 100% concentrations of it are too dangerous to use in uncontrolled environments. It is necessary to find lower percentage concentrations that are safer, yet still effective at dissolving PLA. This paper examined the effectiveness of varying percent concentrations of ethyl acetate on polylactic acid.\u003c/p\u003e","manuscriptTitle":"Investigation into the effects of varying percent concentrations of ethyl acetate on the rate of dissolving polylactic acid","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-19 12:35:39","doi":"10.21203/rs.3.rs-7335944/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":"4fba7709-4094-4ad2-9c6d-9073b38a0f4a","owner":[],"postedDate":"August 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-23T19:23:16+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-19 12:35:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7335944","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7335944","identity":"rs-7335944","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}