PLA/淀粉/蔗渣复合材料自然土埋降解行为研究

摘要

采用自然土埋法研究聚乳酸(PLA)/淀粉(St)/蔗渣(BF)复合材料的降解行为,通过表征复合材料表观形貌、降解率、机械性能、热性能以及微观形貌随降解时间的变化探讨复合材料降解机制.研究表明,降解后复合材料的断面和表面会形成微型孔洞结构,且表面会出现层状剥离现象;淀粉的降解性优于蔗渣,其中,PLA、淀粉和蔗渣质量比为2∶4∶4的复合材料自然土埋2个月的降解率可达到57.35%,远远高于纯聚乳酸的降解率;复合材料的结晶度随着降解的进行不断增大,且聚乳酸的降解始于其无定形区,而后延至其结晶区.%The biodegradable behavior of PLA/Starch/Bagasse composites were investigated by means of natural bury test. The degradation mechanism of the composites were discussed by the variation of apparent morphology, degradation rate, mechanical properties, thermal properties and micromorphology with degradation time. The results showed that the micro hole structure was formed on the section and surface of the composite, and layer stripping phenomenon was appeared on the surface. Degradation test also proved that starch exhibited better biodegradability than bagasse, the degradation percentage of PLA︰St︰BF (2︰4︰4) (in mass ratio) in soil after two month was about 57.35%, which is far higher than pure PLA. In a certain biodegradation time, the crystallinity of the composite was increasing, and the degradation of PLA began from amorphous regions, then extended to crystalline regions.