Abstract
AbstractThe degree of compatibility between poly (lactic acid) (PLA) and different bio‐fillers was examined using thermal methods. The biofillers were fibers extracted from cuphea and lesquerella seeds. Bio‐composites of PLA:Fiber were prepared at 85 : 15, 70 : 30, and 100 : 00 and blended by extrusion and then injection molding. Thermal properties of the extruded (EX) and the extruded‐injection molded (EXIM) composites were examined using differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). Composites analysis using DSC provided information essential for determining: (1) glass transition (Tg); (2) crystallization and melting temperatures and ΔH; (3) percent crystallinity; and (4) Enthalpic Relaxation (ER). TGA was used to measure the mechanism of the thermal decomposition of the composites. The effect of fiber composition, processing conditions, and aging time on the thermal properties of the bio‐composites was used to examine the relative compatibility of the fibers with PLA. The data showed that ER increased steadily as a function of aging. Because of the difference in protein content between cuphea and lesquerella, the two fibers influenced the Tg (temperature and ΔCp) differently. The percent crystallinity of neat PLA was significantly reduced by EX or EXIM, while the enzymatic degradation showed that EX composites are more biodegradable than EXIM. The TGA profiles indicated a multi‐step degradation especially in air. The largest value of q, which indicated that, intermolecular interaction was strongest between lesquerella and PLA extruded materials, compared to the other three blends, possibly due to the higher protein content. Results also indicated that intermolecular interaction was least strong (q = −33.9156) in the EXIM PLA‐cuphea. Although the q values of both cuphea composites were significantly lower than those of the lesquerella samples, this greater effect of extrusion over injection molding on intermolecular interaction was also seen in the q value of the EX and EXIM samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
