Zhou Zibo, Wu Guozhang
Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science & Engineering, East China University of Science & Technology, Shanghai 200237, China.
Polymers (Basel). 2021 Aug 10;13(16):2660. doi: 10.3390/polym13162660.
This study aimed to improve polydimethylsiloxane (PDMS) conversion in the preparation of polycarbonate (PC)-polydimethylsiloxane (PDMS) copolymer through melt polycondensation. We examined the transesterification process of PDMS with diphenyl carbonate (DPC) and its copolymerization products with bisphenol-A (BPA) for different chain lengths of PDMS. The key factors affecting PDMS conversion were investigated. Results showed that long-chain PDMS required a higher critical transesterification level (38.6%) to improve miscibility with DPC. During polycondensation, side reactions were more prone to occur when the equilibrium transesterification level of long-chain PDMS was lower. PDMS conversion was also lower when more short-chain PDMS was fed. Increasing the chain length of PDMS also reduced PDMS conversion. Notably, increasing the amount of KOH can significantly improve PDMS conversion throughout the polycondensation stage by increasing the equilibrium transesterification level of long-chain PDMS, thereby inhibiting the occurrence of side reactions.
本研究旨在通过熔融缩聚提高聚碳酸酯（PC）-聚二甲基硅氧烷（PDMS）共聚物制备过程中聚二甲基硅氧烷（PDMS）的转化率。我们研究了不同链长的PDMS与碳酸二苯酯（DPC）的酯交换过程及其与双酚A（BPA）的共聚产物。研究了影响PDMS转化率的关键因素。结果表明，长链PDMS需要更高的临界酯交换水平（38.6%）来提高与DPC的相容性。在缩聚过程中，当长链PDMS的平衡酯交换水平较低时，副反应更容易发生。当加入更多短链PDMS时，PDMS转化率也较低。增加PDMS的链长也会降低PDMS转化率。值得注意的是，增加KOH的用量可以通过提高长链PDMS的平衡酯交换水平，在整个缩聚阶段显著提高PDMS转化率，从而抑制副反应的发生。
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