不同酶对PBS基共聚酯/淀粉复合材料降解性能的影响

采用L_9(3~3)正交试验对α–淀粉酶降解聚丁二酸丁二酯(PBS)基共聚酯/热塑性淀粉(TPS)复合材料的条件进行了优化,得出α–淀粉酶的最优降解条件为:温度65℃,磷酸盐缓冲液p H=6.8,α–淀粉酶浓度3.5 g/L。利用α–淀粉酶和南极假丝酵母脂肪酶N435对PBS/TPS、聚(丁二酸丁二醇-co-丁二酸二甘醇)酯(PBS-co-DEG)/TPS、聚(丁二酸丁二醇-co-丁二酸乙二醇-co-丁二酸聚乙二醇200)酯(PBES-co-PEG200)/TPS、聚(丁二酸丁二醇-co-丁二酸乙二醇-co-丁二酸聚乙二醇400)酯(PBES-co-PEG400)/TPS复合材料分别进行降解实验,研究了两种酶对这4种复合材料降解性能的影响。结果表明,α–淀粉酶和N435脂肪酶对复合材料均有较好的降解能力,当降解时间较短(6 h)时,α–淀粉酶对复合材料的降解效果优于脂肪酶N435,但当降解时间超过60 h后,后者的降解效果略优于前者;(PBES-co-PEG200)/TPS和(PBES-co-PEG400)/TPS复合材料的降解性能总体上优于(PBS-coDEG)/TPS及PBS/TPS复合材料;随PEG200和PEG400在共聚酯中的含量增加,即醚链含量的增加,相应复合材料的质量损失率呈升高趋势,但当醚链含量较高时,复合材料的质量损失率反而有所下降。

Effects of Different Enzymes on Degradation of PBS-based Copolymer/Starch Composite

L9(33) orthogonal test was adopted to optimize the degradation conditions ofα–amylase for PBS-based copolymer/thermoplastic starch (TPS) composites,then the optimal conditions were obtained,the temperature is 65℃,pH of phosphate buf-fer is 6.8 and concentration ofα–amylase is 3.5 g/L.α–amylase and Lipase Novozym435 were used to degrade the composites of PBS/TPS,(PBS-co-DEG)/TPS,(PBES-co-PEG200)/TPS and (PBES-co-PEG400)/TPS,the effects of the two enzymes on degradation properties of these composites were studied. The results show that bothα–amylase and Lipase Novozym435 have better degradation capability on these composites,when the degradation time is shorter (6 h),the degrading effect ofα–amylase is better than that of Lipase Novozym435,but when the degradation time is over 60 h,the degrading effect of the latter is slightly better than that of the former. The degradation properties of (PBES-co-PEG200)/TPS and (PBES-co-PEG400)/TPS composites are better than those of (PBS-co-DEG)/TPS and PBS/TPS composites in total. With the increase of PEG200 or PEG400 content in PBS-based co-polymer,i.e.,with the increase of ether chain content,the mass loss rates of the composites show increasing tendency,but when the ether chain content is too high,the mass loss rates of the composites decrease instead.