Carboxyl-Terminated Isotactic Polypropylene. Preparation, Characterization, Kinetics, and Reactivities
Carboxyl-Terminated Isotactic Polypropylene. Preparation, Characterization, Kinetics, and Reactivities
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羧基封端的全同立构聚丙烯。
DOI：
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发表时间：
2004
期刊：
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通讯作者：
Mary Kay Tomalia
中科院分区：
文献类型：
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作者：
P. Fu;Mary Kay Tomalia
本文描述了一种简单而高效的方法，通过用硝酸氧化降解市售的结晶聚丙烯，制备含有垂坠硝基的二羧基远链等规聚丙烯。所得结晶聚合物分子量分布窄（Mw/Mn = 2−4），并保持与原聚丙烯相同的等等度。通过改变反应温度、反应时间或硝酸浓度，可以很好地控制产物的分子量。结果表明，反应温度越高，硝酸浓度越高，降解速度越快。动力学研究表明，该反应在硝酸中为4.2阶，表明了反应机理的复杂性。液固和气固两种界面相互作用同时存在于该体系中。可生产低NO2/COOH比的羧盖聚丙烯。
The present contribution describes an unsophisticated yet highly efficient process to make dicarboxyl telechelic isotactic polypropylene containing pendant nitro groups via the oxidative degradation of commercially available crystalline polypropylene with nitric acid. The obtained crystalline polymer has a narrow molecular weight distribution (Mw/Mn = 2−4) and maintains the same degree of isotacticity as the virgin polypropylene. The molecular weights of the product can be well controlled by varying the reaction temperature, reaction time, or the concentration of nitric acid. It was found that the higher reaction temperature and higher concentration of nitric acid, the faster the degradation is. Kinetic studies shown that the reaction is 4.2 orders in nitric acid, indicative of the complex nature of the reaction mechanism. Both liquid/solid and gas/solid interface interactions were found simultaneously existing in the present system. The carboxyl-capped polypropylene with low NO2/COOH ratio can be produce...