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Dual Organocatalysts for Highly Active and Selective Synthesis of Linear Poly(gamma-butyrolactone)s with High Molecular Weights  
Dual Organocatalysts for Highly Active and Selective Synthesis of Linear Poly(gamma-butyrolactone)s with High Molecular Weights
资料类型: PDF文件
关键词: Poly(γ-butyrolactone)s  Ring-opening  polymerization  
资料大小: 1360k
所属学科: 高分子化学
来源: 来源网络
简介:
Ring-opening polymerization (ROP) of the bioderived and nonstrained γ-butyrolactone (γ-BL) is an emerging approach to produce recyclable polymers. It remains a big challenge to synthesize high molecular weight linear poly(γ-butyrolactone)s (PγBLs) in a highly active and selective manner. In this report, we developed dual organocatalysts for the ROP of γ-BL, using symmetrical (thio)ureas with electron-donating groups to buffer the growing anions that were generared by the superbase phosphazene (P4). Linear PγBLs were selectively obtained with high apparent rate constant (ca. 39 times than single P4), and high number-average molecular weights of up to 64.3 kg/mol (ca. 3 times than single P4). The turnover frequencies of these P4/(thio)urea pair-catalyzed processes were as high as 125 h?1. High molecular weight PγBLs exhibited dramatically improved mechanical properties.
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上传时间: 2019-04-01 16:44:53
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