Wahlberg Jessica, Persson Per Valdemar, Olsson Tove, Hedenström Erik, Iversen Tommy
Swedish Pulp and Paper Research Institute, Box 5604, SE-114 86 Stockholm, Sweden.
Biomacromolecules. 2003 Jul-Aug;4(4):1068-71. doi: 10.1021/bm0340725.
The copolymerization of epsilon-caprolactone (epsilon-CL) and d,l-lactide catalyzed by Candida antarctica lipase B was studied. Copolymerizations with different epsilon-CL-to-lactide ratios were carried out, and the product was monitored and characterized by MALDI-TOF MS, GPC, and (1)H NMR. The polymerization of epsilon-CL, which is normally promoted by C. antarctica lipase B, is initially slowed by the presence of lactide. During this stage, lactide is consumed more rapidly than epsilon-CL, and the incorporation occurs dimer-wise with regard to the lactic acid (LA) units. As the reaction proceeds, the relative amount of CL units in the copolymer increases. The nonrandom copolymer structure disappears with time, probably due to a lipase-catalyzed transesterification reaction. In the copolymerizations with a low content of lactide, macrocycles of poly(epsilon-caprolactone) and copolymers having up to two LA units in the ring were detected.
研究了南极假丝酵母脂肪酶B催化的ε-己内酯（ε-CL）与外消旋丙交酯的共聚反应。进行了不同ε-CL与丙交酯比例的共聚反应，并通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）、凝胶渗透色谱（GPC）和核磁共振氢谱（¹H NMR）对产物进行监测和表征。通常由南极假丝酵母脂肪酶B促进的ε-CL聚合反应，最初会因丙交酯的存在而减慢。在此阶段，丙交酯的消耗速度比ε-CL快，并且就乳酸（LA）单元而言，其掺入以二聚体方式发生。随着反应的进行，共聚物中CL单元的相对量增加。非无规共聚物结构随时间消失，这可能是由于脂肪酶催化的酯交换反应。在丙交酯含量低的共聚反应中，检测到了聚（ε-己内酯）大环和环中含有多达两个LA单元的共聚物。
