Synthesis of linear and hyperbranched poly(etherketone)s containing flexible oxyethylene spacers
Synthesis of linear and hyperbranched poly(etherketone)s containing flexible oxyethylene spacers
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含有柔性氧乙烯间隔基的线性和超支化聚醚酮的合成
DOI：
10.1002/pola.22253
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Jong‐Beom Baek
中科院分区：
文献类型：
--
作者：
In‐Yup Jeon;Loon;Jong‐Beom Baek
作为用于聚合物形成反应的弗里德-克来福特酰化反应的强酸反应介质的替代品，具有优化五氧化二磷 (P 2 O 5 ) 量的温和多磷酸 (PPA) 已被测试用于 AB 单体 4-(2-苯氧基乙氧基) 苯甲酸和 3-(2-苯氧基乙氧基) 苯甲酸以及 AB 2 单体的聚合3,5-双(2-苯氧基乙氧基)苯甲酸。 AB 2 单体的反应进程可以通过 FTIR 光谱方便地追踪，监测由链端的羧酸基团和主链中的羰基产生的芳香酮 (C=O) 伸缩带，作为 110 °C 下反应时间的函数。所得含有柔性氧乙烯间隔基的线性和超支化聚合物在高温强酸中易于水解，表现出高特性粘度。因此，作为亲电取代反应的反应介质PPA/P 2 O 5 混合物确实是良性的，不会使生长的聚合物分子解聚，但强度足以从羧酸直接生成碳正离子以促进有效聚合。所得超支化聚醚酮（PEK）在样品中表现出最佳的溶解度。所有PEK均表现出良好的热稳定性；玻璃化转变温度在90-117°C范围内；在空气中温度高于 345°C 时，通常会发生 5% 的重量损失。
As an alternative to strong acid reaction media for the Friedel-Crafts acylation for a polymer-forming reaction, a mild polyphosphoric acid (PPA) with optimized amount of phosphorous pentoxide (P 2 O 5 ) has been tested for the polymerization of AB monomers 4-(2-phenoxyethoxy)benzoic acid and 3-(2-phenoxyethoxy) benzoic acid, and an AB 2 monomer 3,5-bis(2-phenoxyethoxy)benzoic acid. The reaction progress of AB 2 monomer was conveniently traced by FTIR spectroscopy monitoring aromatic ketone (C=O) stretching bands arisen from carboxylic acid groups at the chain ends and carbonyl groups in the backbone as a function of reaction time at 110 °C. The resultant linear and hyperbranched polymers containing flexible oxyethylene spacers, which were prone to be hydrolyzed in strong acids at elevated temperature, displayed high intrinsic viscosities. Thus, the reaction medium PPA/P 2 O 5 mixture as an electrophilic substitution reaction was indeed benign not to depolymerize growing polymer molecules but strong enough for the direct generation of carbonium ion from carboxylic acid to promote efficient polymerization. The resultant hyperbranched poly(etherketone) (PEK) displayed the best solubility among samples. All PEKs showed good thermal stability; glass transition temperatures were in the range of 90-117 °C; 5% weight loss generally occurred at greater than 345°C in air.