两种不同结构共聚酯对脂肪酶降解反应的对比

Comparison of Degradable Perceptibility of Two Different Aliphatic Polyesters with Enzymatic Hydrolysis

采用两种酸一种醇和两种醇一种酸分别对PBS改性,合成了不同化学结构的共聚酯PBSA和PBSH,并在磷酸缓冲液中以它们为底物,研究了对脂肪酶N435降解反应的异同。采用质量损失率和GPC评价了降解前后共聚物分子质量的变化;WAXD和TG分析了酶降解前后共聚物结晶度和热性质的变化;POM对降解后的材料进行了形貌观测。研究结果表明:相比PBS,PBSA和PBSH对脂肪酶的感受性有很大提高,24 h后降解率分别达到90%和60%以上,并且PBSA降解速率比PBSH快很多;降解后2种共聚物相对分子质量变化不大,但分子量分布系数变宽;结晶度增大;降解3 d后PBSA的热稳定性降低,而PBSH的热稳定性提高。

Two kinds of aliphatic copolymers PBSA and PBSH was synthesized by modified PBS with two different diol and diacid respectively. The degradable perceptibility of the eopolymers with the lipase N435 in phosphate was studied. The changes of weight loss rate, relative molecular weight, the degree of crystallinity, thermal stability and crystallization morphology of copolymers in the process of degradation were evaluated by GPC, WAXD, TG and POM. The results showed that compared with PBS, PBSA and PBSH had higher sensitivity in the lipase. The degradation rates of the two eopolymers reached 90% and 60% after 24 h. The degradation rate of PBSA was much faster than PBSH. The relative molecular weight of polymers changed a little during the degradation, but the molecular weight distribution broadened and crystallinities increased. The thermal stability of PBSA decreased while thermal stability of PBSH improved after the degradation for 3 d.