纳米纤维素/聚乳酸复合材料的降解性能

目的研究纳米纤维素/聚乳酸(NCC/PLA)复合薄膜在不同降解条件下的降解情况。方法在p H值为3,7,11的溶液及紫外光照射条件下,降解自制的复合薄膜,通过测失重率、扫描电子显微镜观察、X射线光电子能谱分析等手段,分析p H值、光照和NCC的添加与复合材料降解能力间的关系,研究其降解机理,并与纯PLA薄膜对比。结果 NCC/PLA复合薄膜在碱性条件下质量损失最快,酸性稍慢,中性更慢,紫外光照射下最慢,复合薄膜质量损失均比纯PLA薄膜多。在p H值为3和7的溶液及紫外光照射降解后,NCC/PLA复合薄膜氧碳原子数量的比值均比未降解时增大,分别提高了35.16%,36.66%,38.65%。结论 NCC的添加提高了NCC/PLA复合薄膜的降解性能,在不同降解过程中,薄膜表面C原子所占比例减少,相对地O原子所占比例增加,氧碳原子数量的比值增大。

Degradation Property of the Nano-cellulose Crystal/Poly (Lactic Acid) Composite

This work aimed to study the degradation property of the Nano-cellulose crystal/poly (lactic acid) composite under four different degradation conditions. Degradation experiments were conducted with homemade NCC/PLA composite films in different solutions (pH=3, pH=7 and pH=11) and under ultraviolet, then the relationship between the degradation property of composite films (before and after degradation) and pH, light, NCC was analyzed through the weight loss rate measurement, scanning electron microscopy and X-ray photoelectron spectroscopy. Furthermore, its degradation mechanism was studied, and compared with that of pure PLA films. The degradation rate of NCC/PLA composite films in alkaline condition was the fastest, followed by acidic condition, and then neutral condition, while the degradation in UV irradiation condition was the slowest. The degradation rate of NCC/PLA composite film was faster than that of pure PLA film under different degradation conditions. O/C of NCC /PLA composite film increased after the acid, alkali, ultraviolet degradation by 35.16%, 36.66% and 38.65% respectively as compared to that before degradation. Addition of nano-cellulose crystal improved the degradation property of the NCC/PLA composite film. In different degradation processes, the ratio of carbon atoms on the composite films decreased, and correspondingly the ratio of Oxygen atoms increased, therefore the O/C ratio increased.