溶剂对脂肪酶降解高分子量PBS及改性共聚物的影响

Effect of Solvent on the Enzyme Catalysis Biodegradation of PBS with High Molecular Weight and Its Modified Copolymer

采用固定化脂肪酶分别在四氢呋喃(THF)、甲苯及THF和甲苯的混合溶剂体系中,对高分子量的PBS及PBS/CHDM共聚物进行了催化降解,用GPC测定了降解产物的分子量,用质谱(MS)对降解产物进行了分析,用FTIR表征了产物化学结构.研究结果表明,在脂肪酶的作用下,对Mn在105以上的PBS,在THF体系中可降解到1.4×104,而在甲苯体系中可降解到4×104;但在THF和甲苯的混合体系中,可将Mn105以上的PBS和PBS/CHDM共聚物都可降解为0.1×104以下的原料单体、一至四环状低聚物及少量线型低聚物.分析了水含量对酶解反应的影响.

PBS and PBS/CHDM copolymers with high molecular weight were degraded via immobilized lipase in different polar solvents,such as toluene,tetrahydrofuran,and mixed solvent of toluene and tetrahydrofuran,respectively.The degradation products were analyzed by mass spectrometry（MS）.The chemical structure was characterized by FTIR.And the molecular weight was determined by GPC.Under the function of immobilized lipase,PBS with Mn=100000 can be degraded to Mn=40000 in toluene and to Mn=14000 in tetrahydrofuran system.While in mixed solvent of toluene and tetrahydrofuran,PBS and PBS/CHDM with Mn more than 100000 can be degraded to below Mn=1000.The products almost are monomer,1-4 cyclic oligomer,liner oligomer and a small amount of linear oligomer.The existence of a small amount of water has a certain impact on enzymatic reaction.