Synthesis and comparative biodegradability studies of three poly(alkylene succinate)s
Synthesis and comparative biodegradability studies of three poly(alkylene succinate)s
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DOI：
10.1016/j.polymdegradstab.2005.04.030
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发表时间：
2006-01-01
影响因子：
5.9
通讯作者：
Achilias, DS
中科院分区：
文献类型：
--
作者：
Bikiaris, DN;Papageorgiou, GZ;Achilias, DS
以琥珀酸和具有2~4个亚甲基的脂肪族二醇为原料，通过熔融缩聚合成了聚琥珀酸亚烷基酯。 DSC、H-1 NMR、WAXD 和分子量测量用于表征聚合物。对具有相同平均分子量的聚酯进行的生物降解性研究包括使用德勒马根霉脂肪酶在 pH 7.2 和 30 摄氏度下进行几天的酶水解。生物降解聚酯的 DSC 痕迹表明，水解主要影响无定形材料。所有聚酯的玻璃化转变温度、熔点和熔化热均有所增加。在酶水解的第一天，观察到快速的质量损失，伴随着特性粘度和分子量的快速降低，从而表明混合的内切型和外切型水解机制。此后，它转向外型机制，发生在结晶相中，因为酶水解15-25天后分子量稳定下来，而质量损失继续减少，但速度较慢。端基分析表明，由于酯键断裂，羧基和羟基增加。聚合物的生物降解率按照PPSu > PESu >= PBSu 的顺序降低，这归因于PPSu 与其他聚酯相比结晶度较低，而不是化学结构的差异。最后，开发了一个简单的理论动力学模型并估计了 Michaelis-Menten 参数。 (c) 2005 Elsevier Ltd. 保留所有权利。
Poly(alkylene succinates) were synthesized from succinic acid and aliphatic diols with 2 to 4 methylene groups by melt polycondensation. DSC, H-1 NMR, WAXD and molecular weight measurements were used to characterise the polymers. Biodegradability studies of polyesters with the same average molecular weight, included enzymatic hydrolysis for several days using Rhizopus delemar lipase at pH 7.2 and 30 degrees C. DSC traces of biodegraded polyesters revealed that hydrolysis affected mainly the amorphous material. For all polyesters an increase in glass transition, melting point and heat of fusion was recorded. In the first days of enzymatic hydrolysis, fast rates of mass loss were observed accompanied by a rapid reduction of intrinsic viscosity and molecular weight, thus indicating a mixed endo- and exo-type hydrolysis mechanism. Afterwards, it turned to an exo-type mechanism, taking place in the crystalline phase, since after 15-25 days of enzymatic hydrolysis molecular weight was stabilized, while mass loss kept on decreasing though in a slower rate. End-group analysis revealed that carboxyl and hydroxyl groups increased due to ester bonds' scission. The biodegradation rates of the polymers decreased following the order PPSu > PESu >= PBSu and it was attributed to the lower crystallinity of PPSu compared to other polyesters, rather than to differences in chemical structure. Finally, a simple theoretical kinetic model was developed and Michaelis- Menten parameters were estimated. (c) 2005 Elsevier Ltd. All rights reserved.