Polylactones, 39 : Zn lactate-catalyzed copolymerization of L-lactide with glycolide or ε-caprolactone
Polylactones, 39 : Zn lactate-catalyzed copolymerization of L-lactide with glycolide or ε-caprolactone
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DOI：
10.1002/(sici)1521-3935(19980601)199:6
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发表时间：
1998-06
影响因子：
2.5
通讯作者：
I. Kreiser-Saunders;H. Kricheldorf
中科院分区：
文献类型：
--
作者：
I. Kreiser-Saunders;H. Kricheldorf
乙交酯（Glyc）和L-丙交酯（L-Lac）在150°C下本体共聚以制备无规共聚酯。使用并比较了四种可再吸收的催化剂：ZnCl 2、ZnO 2、硬脂酸锌（ZnSte 2）和乳酸锌（ZnLac 2）。通过1H NMR光谱法记录乙交酯和丙交酯的单独的时间-转化率曲线。乙交酯的聚合速度比L-丙交酯在所有情况下，但差异最小时，ZnLac 2作为催化剂。使用13 C NMR光谱进行序列分析。完全随机的序列从未获得，但由ZnLac 2催化产生的序列最接近所需的随机性。用ZnSte 2和ZnLac 2进行了1：1（摩尔比）的聚合。两种催化剂都获得了高产率，但ZnLac 2产生了更高的分子量。此外，ZnLac 2催化的共聚进行了与不同的甘氨酸/紫胶比。发现小规模和大规模共聚产生具有不同性质的共聚酯，因为在聚合的早期阶段的过热（由乙交酯产生）有利于酯交换。最后，在150°C下本体研究了ε-己内酯和L-丙交酯的1：1共聚。再次获得高产率、高分子量和几乎随机的序列。
Copolymerizations of glycolide (Glyc) and L-lactide (L-Lac) were conducted at 150°C in bulk to prepare random copolyesters. Four resorbable catalysts were used and compared: ZnCI 2 , ZnO 2 , Zn stearate (ZnSte 2 ) and Zn lactate (ZnLac 2 ). Separate time-conversion curves were recorded for glycolide and lactide by means of 1 H NMR spectroscopy. Glycolide polymerized faster than L-lactide under all circumstances, but the difference was smallest when ZnLac 2 was used as catalyst. Sequence analyses were performed using 13 C NMR spectroscopy. Completely random sequences were never obtained, but the sequences resulting from a catalysis with ZnLac 2 came closest to the desired randomness. Preparative 1:1 (mole ratio) polymerizations were conducted with ZnSte 2 and ZnLac 2 . High yields were obtained with both catalysts, but ZnLac 2 yielded far higher molecular weights. Furthermore, ZnLac 2 -catalyzed copolymerizations were conducted with variation of the Glyc/Lac ratio. It was found that small scale and large scale copolymerizations yield copolyesters having different properties, because the superheating in the early stage of the polymerizations (resulting from glycolide) favors the transesterification. Finally, 1:1 copolymerization of e-caprolactone and L-lactide were studied in bulk at 150°C. Again high yields, high molecular weights and nearly random sequences were obtained.