聚乳酸/聚(羟基丁酸-羟基戊酸共聚酯)共混物的水降解性能

Hydrolytic Degradation Properties of Poly(lactic acid)/Poly(3-hydroxybutyrate-co-hydroxyvalerate)Blends

为了研究聚(羟基丁酸-羟基戊酸共聚酯)(PHBV)的加入对聚乳酸(PLA)降解性能的影响,采用溶液浇铸法制备了不同质量比的PLA/PHBV共混物,对其在不同pH值的PBS缓冲液中降解前后的质量损失率、吸水率、形貌、结晶和热性能变化进行了研究。结果表明,PLA/PHBV共混物的质量损失率和吸水率在碱性缓冲液中增加最快,酸性溶液中次之,中性溶液中最慢;PHBV的加入在碱性缓冲液中促进PLA的降解,在酸性和中性缓冲液中则起阻碍作用;随降解时间的延长,光滑表面变为凹凸不平并出现许多孔洞,共混物的结晶度先提高后降低,其晶型结构未发生改变;降解使共混物的熔融峰向低温偏移。

In order to study the effect of poly（3-hydroxybutyrate-co-hydroxyvalerate）（PHBV）addition on the degradation of poly（lactic acid）（PLA）,PLA/PHBV blends with different mass ratio were prepared by solution casting method.The mass loss rate,water absorption rate,crystalline structure surface morphology and thermal properties of the buffer solution with different pH were analyzed before and after degradation.The results show that the mass loss rate and water absorption of PLA/PHBV blends increase fastest in alkaline buffer,followed by acidity and slowest in neutral solution.The addition of PHBV promotes the degradation of PLA in alkaline buffer,and is a hindrance in acidic and neutral buffers.As the degradation time increases,the smooth surface becomes uneven and many voids appear.The crystallinity of the blends increases first and then decreases,but the crystalline structure of the blends does not change.The melt peak of the blends shifts to low temperature after degradation.