Progress 09/01/12 to 05/31/15
Outputs
Target Audience:This project provides opportunities to sustain and enhance the domestic plastics industries, the fourth largest manufacturing sector of the American economy. Technological improvements in available bioplastics will expand the markets for value added biobased industrial products. Accordingly, the proposed research directly supports the Sustainable Bioenergy Challenge research priority of the USDA. In addition, bioplastic materials are derived from agricultural materials and will help reduce the U.S. dependence on foreign oil. The goal of this Phase II project was to develop an impact modified bionanocomposite that is 100% based on renewable resources to produce disposable cutlery. This will provide consumers and suppliers with an environmentally sustainable choice for disposable cutlery. Changes/Problems:Midway through the first year of the project, personnel changes at PolyNew required substitution of the original PI (Dr. Jay Hotchkiss). Fortunately, one of the co-PIs (Hollingsworth) was intimately familiar with the project and was able to assume the role of PI. We also hired a Ph.D. level Lead Scientist, Dr. Bo Liu, to help technically guide the project. Dr. Liu has significant previous experience with PLA cellulosic nanocomposites as well as industrial polymer extrusion experience. Accordingly, this issue was fully resolved. Larger scale production of whiskers had been bottled-necked at the drying stage. PolyNew investigated several techniques to reduce the volume of water to be removed during drying which has resulted in a doubling of the production rate. The nanocomposite samples sent to Johns Hopkins University for biodegradation studies could not be fully evaluated. The group at Johns Hopkins University has had numerous issues getting the biodegradation studies running. These tests can take more than 6-months to complete. Far into the testing on PolyNew's materials it was noticed that the PLA blends were biodegrading at a slower rate than expected. Initially, the culture used was not optimized correctly for PLA. The group at Johns Hopkins University has started using a more robust mixed culture and has started working with a more specialized microorganism for degrading the PLA. Although results so far are promising, the experiments will take several months to complete and will not see results by the end of the performance period of this project. What opportunities for training and professional development has the project provided?Professional development has been enhanced while simultaneously reaching the technical objectives and project milestones. Mr. Rodolfo Sosa has gained experience interfacing with other research groups and expanded his knowledge of biodegradation testing and protocols. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The goal of this Phase II project was to develop a novel polymeric impact modifier that is 100% based on renewable resources and can be economically processed. Polylactide (PLA) is a commercially available bioplastic that is also biodegradable; however, it is a brittle plastic with low impact strength so there is a clear market need for a modifier that improves properties while maintaining biodegradability. In the novel approach pursued by PolyNew, the impact improvement achievable from blending with another biodegradable polymer (poly(butylene succinate) (PBS)) is enhanced through the use of reinforcing cellulosic nanowhiskers (CNWs); this novel and biodegradable nanofiller helps improve rigidity and heat stability. The CNWs improve the toughness and heat distortion temperature while maintaining modulus and without compromising the biodegradable nature of the base bioplastic. Developing a new plastic material with suitable properties is a necessary but not sufficient criterion for successful commercialization. This is because raw material costs do not fully dictate the economics of manufacturing. Of equal importance is cycle time, which is how rapidly the articles can be manufactured. Capital and labor costs can be amortized to an hourly basis and the faster the cycle time the more units manufactured and the lower the unit cost. PolyNew completed all of the programmatic objectives. The objective of producing PBS/CNW/PLA nanocomposites with superior thermal and mechanical properties has been reached. The materials used in the nanocomposite are bio-based and biodegradable. These nanocomposites have been successfully used for the pilot-scale production of biodegradable plastic cutlery on standard injection molding equipment. Replacing conventional disposable plastic products with bio-based, biodegradable materials has the ability to increase domestic bioresource markets, reduce solid waste, and create green jobs. Progress on Original Task Plan During the performance period, the proposed Task Plan was executed with little deviation. We optimized the cellulose nanowhisker production and scaled up for large quantity production. The nanocomposites incorporating stereocomplexation with nanowhiskers were evaluated. The pilot-scale extrusion operation to blend the nanocomposites was reconfigured and optimized by designing and manufacturing a new extrusion die. Large batches of nanocomposites were made for prototype utensil production. Prototype utensils were produced using an industrial size injection molding machine. Laboratory procedures for mechanical testing were also developed and the material and mechanical properties of the utensils produced were evaluated. Task 1. Produce nanocomposites in large enough quantities to allow pilot scale testing. The objective of this task was to produce material batches, in the form of plastic pellets, in quantities to allow pilot injection molding. The production of CNW was continuously scaled up and large quantities of materials were produced. The material formulations were screened and the processing was optimized. A large series of materials were made to evaluate the effects of filler type and stereocomplex presence. Previous work had fixed the filler level at 15 wt % and the optimum PDLA level for stereocomplexation at 25 wt% of the PLA fraction. To evaluate the materials and select the most promising ones for prototype cutlery production, dynamic mechanical analysis (DMA) was used to obtain modulus data and to determine heat distortion temperatures (HDT). The data showed the synergistic effect of both PDLA and filler on the properties of the nanocomposites. Addition of both filler and stereocomplex results in increased HDT and modulus. The PDLA-grafted fillers resulted in similar properties to that of physisorbed samples. Based on the results of the DSC and DMA testing, two formulations were selected to make prototype utensils. One formulation contained CNW and one formulation contained silica, all in a PLA/PBS matrix including stereocomplexation. Task 2: Injection mold the biodegradable nanocomposites into cutlery The purpose of this task was to evaluate the material suitability for high speed manufacturing by performing a series of trials using a 30 ton injection molding machine. Materials were molded under different processing conditions (mold temperature, ram rates, pressures, and hold times) to optimize the processing and resulting properties. The collected cutlery samples were examined for qualitative (feel and look) and quantitative (modulus, impact, and heat distortion temperature) properties in Task 3. A Sumitomo (SHI) direct-drive all-electric injection molding machine was used for the prototype cutlery production. The extrusion and injection molding parameters were optimized for each material. All equipment used was standard manufacturing equipment. Both forks and spoons were successfully produced. Task 3. Evaluate the properties of the cutlery made from the bioplastic nanocomposites. The cutlery produced was evaluated qualitatively based on look and feel. In addition, the materials used for cutlery production were again evaluated by DMA and DSC for thermo-mechanical properties after injection molding. The forks and spoons produced from the nanocomposite materials looked smooth and shiny. The material was pigmented black and the color was consistent throughout the utensils. They also had a smooth feel to the mouth and hand. DMA testing data showed the improved modulus and HDT properties of the PLA nanocomposites compared to both PLA and PLA/PBS control materials. Addition of CNW as filler maintains the glassy modulus to that of the pure PLA while significantly increasing the HDT to over 97 °C. Task 4. Use data to establish best manufacturing practices. During the pilot-scale cutlery production and subsequent testing, preliminary operating conditions for prototype manufacturing were established. Materials preparation, compounding and injection molding were optimized and cutlery was able to be produced using conventional manufacturing equipment. Suitable manufacturing equipment and practices are well documented and ready to use in high volume production in the future. Post-injection annealing was investigated, and an appropriate annealing procedure was developed. Annealing in the economically favorable temperature range of 110 to 145°C out of the mold provides adequate properties. Task 5. Evaluate the manufacturing viability of second generation biodegradable cutlery It has been demonstrated that the second generation biodegradable cutlery can be manufactured on conventional polymer processing equipment including compounding and injection molding. The resulting cutlery has a good look and feel. Chemical grafting of polymer chains onto the surface of the nanoparticles is not required because polymer chain physisorption during pre-blending is adequate to achieve good composite mixing. This is important because a chemical grafting process is eliminated to simplify the manufacturing steps, also resulting in a lower manufacturing cost. Key Outcomes and Accomplishments PolyNew completed all of the programmatic objectives. The team was able to produce sufficient quantities of CNWs for evaluation purposes. Preliminary processing conditions and formulations were identified and evaluated. Most importantly the production of PBS/CNW/PLA nanocomposites with superior thermal and mechanical properties was reached. These nanocomposites have been used for the pilot-scale production of biodegradable plastic cutlery on standard injection molding equipment with no problems. Such technological improvements expand the markets for value-added biobased industrial products. Disposable cutlery is the main market being targeted, but other markets could include things like disposable razors and other disposable food service products.
Publications
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience: This project provides opportunities to sustain and enhance the domestic plastics industries, the fourth largest manufacturing sector of the American economy. Technological improvements in available bioplastics will expand the markets for valueadded biobased industrial products. Accordingly, the proposed research directly supports the Sustainable Bioenergy Challenge research priority of the USDA. In addition, bioplastic materials are derived from agricultural materials and will help reduce the U.S. dependence on foreign oil. The goal of this Phase II project is to develop an impact modified bionanocomposite that is 100% based on renewable resources to produce disposable cutlery. This will provide consumers and suppliers with an environmentally sustainable choice for disposable cutlery. Changes/Problems: No major changes or problems were encountered during the last reporting period. Larger scale production of whiskers had been bottled-necked at the drying stage. PolyNew investigated several techniques to reduce the volume of water to be removed during drying which has resulted in a doubling of the production rate. PolyNew is investigating the newly available commercial cellulose nanocrystals (CNC) from the USDA Forest Products Laboratory (and the University of Maine) which could be a possible economical solution for high volume CNC production. What opportunities for training and professional development has the project provided? Professional training has been enhanced while simultaneously reaching the technical objectives and project milestones. A female high school student with an interest in the sciences was employed as a part time laboratory technician/intern. Under the supervision of Dr. Liu she has developed new skills and insight by working in a professional research laboratory. She learned basic chemical handling techniques, safety procedures and techniques for maintaining glassware and equipment, and the importance of recordkeeping in the laboratory. Such basic knowledge can be widely applied in a college laboratory setting or as a practicing scientist. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? PolyNew plans to continue to execute the Project Task Plan as proposed. The prototypical cutlery produced will be subjected to "real-life" testing, as well as mechanical testing. Samples have been submitted to Intertek Plastics Testing Lab for tensile and impact tests. The nanocomposite formulation and production parameters will be adjusted as necessary. In addition, the nanocomposite material is being subjected to biodegradation testing in accordance withISO 14851 and ASTM D5988-03 .
Impacts
What was accomplished under these goals?
The now rapidly developing field of plastic materials based on renewable resources (bioplastics) provides tremendous opportunities to sustain and enhance the domestic plastics industries, the fourth largest manufacturing sector of the American economy. These new technologies have significant ability to create new green jobs. Growth in the use of these new, greener plastics is proceeding rapidly. However, there are a number of cases in which bioplastics lack the properties needed to compete with increasingly expensive petroleum based materials. These property limitations can be overcome and such technological improvements expand the markets for value-added biobased industrial products. The goal of this Phase II project is to develop a novel polymeric impact modifier that is 100% based on renewable resources and can be economically processed. Polylactide (PLA) is a commercially available bioplastic that is also biodegradable; however, it is a brittle plastic with low impact strength so there is a clear market need for a modifier that improves properties while maintaining biodegradability. In the novel approach pursued by PolyNew, the impact improvement achievable from blending with another biodegradable polymer (poly(butylene succinate) (PBS)) is enhanced through the use of reinforcing cellulosic nanowhiskers (CNWs). The strength is improved while maintaining modulus and without compromising the biodegradable nature of the base bioplastic. In the development of new plastic products, developing a material with suitable properties is a necessary but not sufficient criterion for successful commercialization. This is because raw material costs do not fully dictate the economics of manufacturing. Of equal importance is cycle time, that is how rapidly the articles can be manufactured. Plastics processing is an advanced technology and cycle times are amazingly short, oftentimes less than a second. To proceed to full commercialization, it is necessary to demonstrate that the sustainable nanocomposites can be economically processed. Progress on Original Task Plan During the performance period, the proposed Task Plan was executed with little deviation to achieve the project objectives. A large portion of time was still spent on Task 1, producing the nanocomposite materials to be evaluated. Nanocomposite composition was optimized and an additional filler was tested. Progress was also made on Tasks 2, 3 ,4, and 5. Large batches of nanocomposites were produced and prototype cutlery was fabricated. Task 1. Produce nanocomposites in large enough quantities to allow pilot scale testing. The objective of this task is to produce material batches, in the form of plastic pellets, in quantities to allow pilot injection molding. The production of CNW was continuously scaled up and large quantities of materials were produced. The material formulations were screened and the processing was also optimized. Recent promising results with grafted silica prompted PolyNew to also evaluate silica as a filler in the nanocomposite formulations. A series of materials were made to evaluate the effects of filler type and stereocomplex presence. Previous work had fixed the filler level at 15 wt % and the optimum PDLA level for stereocomplexation at 25 wt% of the PLA fraction. To evaluate the materials and select the most promising ones for prototype cutlery production, the percent crystallinity and melting temperatures (Tm) were measured by differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) was used to obtain modulus data and to determine heat distortion temperatures (HDT). The data showed the synergistic effect of both PDLA and filler on the properties of the nanocomposites. Addition of both filler and stereocomplex results in increased HDT and modulus. The PDLA-grafted fillers resulted in similar properties to that of physisorbed samples. Based on the results of the DSC and DMA testing, two formulations were selected to make prototype utensils. One formulation contained CNW and one formulation contained silica, all in a PLA/PBS matrix including stereocomplexation. Task 2: Injection mold the biodegradable nanocomposites into cutlery The purpose of this task was to evaluate the material suitability for high speed manufacturing by performing a series of trials using a 30 ton injection molding machine. Materials were molded under different processing conditions (mold temperature, ram rates, pressures, and hold times) to optimize the processing and resulting properties. The collected cutlery samples were examined for qualitative (feel and look) and quantitative (modulus, impact, and heat distortion temperature) properties in Task 3. Injection molding trials were conducted at the Composite Materials and Engineering Center at Washington State University in Pullman, Washington. A Sumitomo (SHI) direct-drive all-electric injection molding machine was used for the prototype cutlery production. The extrusion and injection molding parameters were optimized for each material. All equipment used was standard manufacturing equipment. Both forks and spoons were successfully produced. Task 3. Evaluate the properties of the cutlery made from the bioplastic nanocomposites. The cutlery produced was evaluated qualitatively based on look and feel. In addition, the materials used for cutlery production were again evaluated by DMA and DSC for thermo-mechanical properties after injection molding. The forks and spoons produced from the nanocomposite materials looked smooth and shiny. The material had been pigmented black and the color was consistent throughout the utensils. They also had a good smooth feel to the mouth and hand. DMA testing data showed the improved modulus and HDT properties of the PLA nanocomposites compared to both PLA and PLA/PBS control materials. Addition of CNW as filler maintains the glassy modulus to that of the pure PLA while significantly increasing the HDT to over 97 °C. Task 4. Use data to establish best manufacturing practices. During the pilot-scale cutlery production and subsequent testing, preliminary operating conditions for prototype manufacturing were established. Materials preparation, compounding and injection molding were optimized and cutlery was able to be produced using conventional manufacturing equipment. Suitable manufacturing equipment and practices are well documented and ready to use in high volume production in the future. Post-injection annealing has been investigated, and an appropriate annealing procedure has been developed. Annealing in the economically favorable temperature range of 110 to 145°C out of the mold provides adequate properties. Task 5. Evaluate the manufacturing viability of second generation biodegradable cutlery It has been demonstrated that the second generation biodegradable cutlery can be manufactured on conventional polymer processing equipment including compounding and injection molding. Chemical grafting of polymer chains onto the surface of the nanoparticles is not required because polymer chain physisorption during pre-blending is adequate to achieve good composite mixing. This is important because a chemical grafting process is eliminated to simplify the manufacturing steps, also resulting in a lower manufacturing cost. Key Outcomes and Accomplishments PolyNew has made excellent progress across the programmatic objectives. The team is successfully progressing through the Task Plan and has reached the significant milestones. As discussed in the Progress on Task Plan sections, PolyNew was able to produce sufficient quantities of CNWs for evaluation purposes, and has produced large batches of nanocomposites. Most importantly, the major milestone of synthesizing CNW nanocomposites with good heat resistance and improved mechanical properties has been reached. Pilot production of cutlery has been performed and the initial extrusion and injection molding parameters for the cutlery have been dialed in.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2014
Citation:
Dorgan, J.R. (2014 June) "Supramolecular EcoBioNanocomposites Incorprating Stereocomplexation" Paper presented at 2014 TAPPI International Conference on Nanotechnology for Renewable Materials, Vancouver, British Columbia, Canada.
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience: This project provides opportunities to sustain and enhance the domestic plastics industries, the fourth largest manufacturing sector of the American economy. Technological improvements in available bioplastics will expand the markets for value-added biobased industrial products. Accordingly, the proposed research directly supports the Sustainable Bioenergy Challenge research priority of the USDA. In addition, bioplastic materials are derived from agricultural materials and will help reduce the U.S. dependence on foreign oil. The goal of this Phase II project is to develop an impact modified bionanocomposite that is 100% based on renewable resources to produce disposable cutlery. This will provide consumers and suppliers with an environmentally sustainable choice for disposable cutlery. Changes/Problems: Problems Encountered Midway through the first year of the project, personnel changes at PolyNew required substitution of the original PI (Dr. Jay Hotchkiss). Fortunately, one of the co-PIs (Hollingsworth) was intimately familiar with the project and was able to assume the role of PI. We have also hired a new Ph.D. level Lead Scientist, Dr. Bo Liu, to help technically guide the project through Phases II and III. Dr. Liu has significant previous experience with PLA cellulosic nanocomposites as well as industrial polymer extrusion experience. Accordingly, this issue has been fully resolved. Larger scale production of whiskers had been bottled-necked at the drying stage. PolyNew investigated several techniques to reduce the volume of water to be removed during drying which has resulted in a doubling of the production rate. Further optimization will continue. The molecular weight of the PBS material will need to be increased to obtain the mechanical properties reached by the commercial PBS used in the study. Work on improving the molecular weight of the condensed PBS continues. What opportunities for training and professional development has the project provided? Professional development has been enhanced while simultaneously reaching the technical objectives and project milestones. Mr. Rodolfo Sosa has benefitted greatly in this project from the tutelage of Dr. Jay Hotchkiss and Dr. Bo Liu. Under their guidance, Mr. Sosa gained proficiency in using TEM and NMR. These two instrumental methods have wide applicability and are particularly useful in the realm of polymer nanocomposites. As a result of his engaging employment at PolyNew, Mr. Sosa is now considering entering a graduate program in chemistry to earn his Ph.D. In addition, Mr. Clay Perbix, a 2012 chemical engineering BS graduate, has also developed new skills and expertise. Working with our consultant, Professor John Dorgan, an FTIR technique for measuring the degree of surface substitution of the CNWs has been transferred from academia to the small business. As a result of these activities, Mr. Perbix now has a thorough understanding of the fundamental principles and practical uses of FTIR. Such spectroscopic methods can be widely applied as a practicing chemical engineer. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? PolyNew plans to continue to execute the Project Task Plan as proposed. Addtional batches of the most promising CNWs have been prepared, and a range of the downselected nanocomposite formulations are being produced. The mechanical properties of these nanocomposites will be evaluated, and the most promising formulations will carried forward to prototyping. Plans are set for injection molding trials to produce sample cutlery.
Impacts
What was accomplished under these goals?
The now rapidly developing field of plastic materials based on renewable resources (bioplastics) provides tremendous opportunities to sustain and enhance the domestic plastics industries, the fourth largest manufacturing sector of the American economy. Accordingly, these new technologies have significant ability to create new green jobs. This is because these plastics will be made from domestically sourced bioresources rather than from petroleum. The use of bioplastics helps reduce the U.S. dependence on foreign oil. Bioplastics also provide greater consumer choice. Growth in the use of these new, greener plastics is proceeding rapidly. However, there are a number of cases in which bioplastics lack the properties needed to compete with increasingly expensive petroleum based materials. Drawing on decades of scientific knowledge about polymer blends and the emerging field of polymer nanocomposites, these property limitations can be overcome. Such technological improvements expand the markets for value-added biobased industrial products. In doing so, this research directly supports the Sustainable Bioenergy Challenge research priority of the USDA. The goal of this Phase II project is to develop a novel polymeric impact modifier that is 100% based on renewable resources and can be economically processed. Polylactide (PLA) is a commercially available bioplastic that is also biodegradable; however, it is a brittle plastic with low impact strength so there is a clear market need for a modifier that improves properties while maintaining biodegradability. In the novel approach pursued by PolyNew, the impact improvement achievable from blending with another biodegradable polymer (poly(butylene succinate) (PBS)) is enhanced through the use of reinforcing cellulosic nanowhiskers (CNWs). The impact strength is improved while maintaining modulus and strength and without compromising the biodegradable nature of the base bioplastic. In the development of new plastic products, developing a material with suitable properties is a necessary but not sufficient criterion for successful commercialization. This is because raw material costs do not fully dictate the economics of manufacturing. Of equal importance is cycle time, that is how rapidly the articles can be manufactured. Capital and labor costs can be amortized to an hourly basis and the faster the cycle time the more units manufactured and the lower the unit cost. Plastics processing is an advanced technology and cycle times are amazingly short, oftentimes less than a second. To proceed to full commercialization, it is necessary to demonstrate that the sustainable nanocomposites can be economically processed. Progress on Original Task Plan During the performance period, the proposed Task Plan was executed with little deviation to achieve the project objectives. A large portion of time was spent on Task 1, producing the nanocomposite materials to be evaluated. The pilot-scale extrusion operation to blend the nanocomposites was studied and optimized. Laboratory procedures for mechanical testing were also developed and the material properties of the first nanocomposites produced were evaluated. Task 1. Produce nanocomposites in large enough quantities to allow pilot scale testing. The objective of this task is to produce material batches, in the form of plastic pellets, in quantities to allow pilot injection molding. Several such batches with variations in the details of their formulations are needed. 1.1. Scale-up of the successful functionalized nanowhisker production process: PolyNew developed experimental protocols for the simultaneous isolation and lactic acid functionalization of CNWs in Phase I. This new “one-pot” methodology has the advantage of eliminating energy and capital intensive separation steps leading to superior life cycle analysis (LCA) performance. This process was optimized during the last period to enable a doubling of the production rate of LA-CNW. 1.2. Continued laboratory scale experimentation to optimize the synthesis and formulations: The cellulose whiskers successfully obtained from Task 1.1 were blended with PLA and PBS at concentrations varying from 0 to 25 wt%. Wrapped LACNWs (poly-LACNW) using 2 different molecular weight wrapping polymers (Poly1-50 and Poly1-500) were also blended with PLA and PBS at different concentrations. In all cases, the mass ratio of PLA to PBS was 85% to 15% based on experiments conducted earlier. The blends were evaluated by dynamic mechanical analysis (DMA) to determine the modulus and heat distortion temperature (HDT). The DMA data from these blends is presented in Figure 1. Figure 1: Mechanical Properties of Melt Pressed Films of PLA/PBS/LACNW Blends Although the addition of PBS to PLA increases its impact strength, it reduces its HDT and modulus. This can be seen in Figure 1 by comparing the 100/0/0 sample to the 85/15/0 sample (the material without any nanofiller). Blending LACNW with the PLA/PBS to create a nanocomposite helps to bring the HDT and modulus back up to the level of neat PLA, however, using Poly-LACNW results in even higher modulus and HDT values. The target HDT of 100°C (which enables the containment of boiling water)can be reached using poly-LACNW at 25 wt%. 1.3. Configure the pilot scale extruder and associated mixing equipment. A small pilot extruder was configured to perform mixing and extrusion of the nanocomposite blends. A Haake Rheomix 202 single screw extruder was attached to the Haake Rheodrive 5000 mixer. A single strand die was used. The extruder configuration is shown in Figure 2. The extruder has two temperature control zones in the barrel and a heating band was added to the die to control the final melt temperature. A water bath with ice was set up beneath the die, and the strand was pulled through the water bath to cool before pelletizing. Figure 2: Haake Extruder Setup 1.4 Developing the extrusion process to melt mix the functionalized nanowhiskers with PLA and PBS to enable production of the biodegradable nanocomposites. All extrusions were performed in the Haake single screw extruder. Temperature settings are well-known for this material, so little variation in temperature was investigated. The main parameters investigated were screw speed and number of passes. Materials were initially processed at 25 RPM. A single formulation of 85/15/15 PLA/PBS/LACNW was fed through the extruder multiple times at 100 RPM. The material was run through the extruder a total of 3 times. After each pass a sample of the material was collected for DMA. DMA data is shown in Table 1. For comparison, DMA data for the same nanocomposite composition produced at 25 rpm is also shown in Table 1. With multiple passes through the extruder, slight degradation is seen through a decrease in the modulus and HDT. With the slight decrease in mechanical properties shown in Table 1, these data suggest that multiple passes through the extruder may not be beneficial at high screw speeds. The increase in speed to from 25 rpm to 100 rpm was likely enough to give sufficient mixing instead of using multiple passes, as seen by the modulus and HDT values in Table 1. Key Outcomes and Accomplishments PolyNew has made excellent progress across the programmatic objectives. The team has been able to produce sufficient quantities of CNWs for evaluation purposesand has even improved the CNW properties and production process. Preliminary processing conditions and formulations have been identified and evaluated. Most importantly, a major milestone – the production of PBS/CNW/PLA nanocomposites with superior properties– has been reached. These CNW nanocomposites appear to have excellent dispersion of the CNW nanofiller and good color properties. It is apparent that these materials are suitable for the production of biodegradable plastic cutlery, the main market being targeted.
Publications
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