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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 acid and one kind of alcohol and two kinds of alcohol and one kind of acid were respectively used to modify PBS to synthesize copolyesters PBSA and PBSH with different chemical structures. Using phosphate buffer as substrate, the lipase N435 The similarities and differences of degradation reaction. The mass loss rate and GPC were used to evaluate the molecular weight of the copolymer before and after degradation. WAXD and TG were used to analyze the changes of crystallinity and thermal properties of the copolymer before and after degradation. POM was used to observe the morphology of the degraded material. The results showed that compared with PBS, PBSA and PBSH greatly increased the susceptibility to lipase, and the degradation rates reached 90% and 60% respectively after 24 h, and the degradation rate of PBSA was much faster than that of PBSH. After degradation, the two copolymers The relative molecular mass changed little, but the molecular weight distribution coefficient broadened; the crystallinity increased; the thermal stability of PBSA decreased after 3 d of degradation, but the thermal stability of PBSH increased.