Controlling melt reactions during preparing long chain branched polypropylene using copper N,N-dimethyldithiocarbamate
Controlling melt reactions during preparing long chain branched polypropylene using copper N,N-dimethyldithiocarbamate
复制标题
DOI：
10.1016/j.polymer.2010.01.063
复制
发表时间：
2010-03
期刊：
影响因子：
4.6
通讯作者：
Zhen-jiang Zhang;Haiping Xing;J. Qiu;Zhiwei Jiang;Haiou Yu;Xiaohua Du;Yan-hui Wang;L. Ma;T. Tang
中科院分区：
文献类型：
--
作者：
Zhen-jiang Zhang;Haiping Xing;J. Qiu;Zhiwei Jiang;Haiou Yu;Xiaohua Du;Yan-hui Wang;L. Ma;T. Tang
研究了N，N-二甲基二硫代氨基甲酸铜（CDD）对自由基接枝法制备长链支链聚丙烯（LCB-PP）过程中熔融反应的影响。对改性聚苯乙烯的结构和流变性能进行了表征。结果表明，CDD能有效控制过氧化氢存在下PP骨架降解和多功能单体（三甲基丙烷三丙烯酸酯（TMPTA））的均聚反应。同时，CDD的加入也提高了LCB结构的形成效率。CDD与活性自由基（碳中心自由基和烷氧基自由基）反应形成原位二硫代氨基甲酸酯自由基，该自由基不能攻击PP主链，是TMPTA较弱的引发剂。合成的二硫氨基甲酸酯自由基能与PP自由基和丙烯酸自由基发生可逆反应，延长了PP自由基的寿命，增加了自由基之间的反应概率。得到的LCB-PP具有较高的熔体强度。
Effect of copper N,N-dimethyldithiocarbamate (CDD) on melt reactions during preparing long chain branched polypropylenes (LCB-PP) via free radical grafting was studied. The structure and rheological properties of the modified PPs were characterized. The results showed that CDD could efficiently control two side reactions, i.e. degradation of PP backbone and homopolymerization of multifunctional monomer (trimethylol propane triacrylate (TMPTA)) in the presence of peroxide. Meanwhile the addition of CDD also increased the efficiency of forming LCB structure. The reaction between CDD and active free radicals (carbon centered and alkoxy species) led to forming in situ dithiocarbamate radicals, which cannot attack PP backbone and are weaker initiator for TMPTA. The resultant dithiocarbamate radicals could react with the PP macroradicals and the acrylic radicals reversibly, which prolong the life time of PP macroradical and increase the reaction probability between macroradicals. The obtained LCB-PP showed high melt strength.