Studies on Compatibility and Biodegradability of PHB/PLA Blends

• Main Authors: Yi-Hsun Liu, 劉義峋
• Other Authors: Trong-Ming Don
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/17554675488298979854

碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 99 === Biodegradable polymers have recently attracted great attension because environmental pollution. PLA and PHB is a aliphatic thermoplastic polyester and a biodegradation plastic. In this study, we blended PLA with PHB. We hope it could have a good miscibility and increase the mechanical properties. Then we measure the physical properties and mechanical properties. Finally, we degrade the PHB/PLA blends by streptomyces 76T-1 to investigate the degradability of PHB/PLA blends. Because the miscibility was increased by reduceing the molecular weight of PHB, we blend PLA with PHB by mixer at 180oC for 20 min to obtain the low molecular weight PHB blend with PLA. We could increase the crystallinity of PLA by adding the low molecular weight PHB.The elongation at break was increased from 7% to 226% by blending 20 wt% PHB. We use Streptomyces sp. 76T-1 to degrade PLA and PHB/PLA blends. After degradating test in 72 hour, PLA could be degradating completely. Adding 5 wt% low molecular weight PHB could accelerate the degradating rate, because the low crystallinity of PLA after adding 5 wt% PHB. But adding PHB more then 10 wt% could slow down the degradating rate. After degradating test, we found that the crystallinity was changed by the environment temperature not by degrading of Streptomyces sp. 76T-1. In the other word, the crystallinity have not changing in the degrade behavior.