尼龙66/乙烯-醋酸乙烯酯共聚物接枝马来酸酐共混体系的研究 (Ⅰ)乙烯-醋酸乙烯酯共聚物熔融接枝马来酸酐的制备与表征

Study on the blending system of MAH grafted nylon 66/EVA copolymer (Ⅰ)Preparation and characterization of MAH grafted EVA copolymer

以马来酸酐为单体、过氧化物为引发剂 ,采用熔融挤出法制备了乙烯 醋酸乙烯酯共聚物接枝马来酸酐 (EVA g MAH)。重点讨论了不同型号的EVA、过氧化物引发剂品种及用量、单体MAH用量和加工工艺条件等因素对接枝反应的影响。通过化学滴定法和傅立叶红外光谱法 (FTIR)证实部分马来酸酐确实以化学键连接到EVA分子链上。与聚乙烯 (PE)、聚丙烯 (PP)相比 ,EVA中由于含有醋酸乙烯 (VA)基团 ,极性较大 ,与MAH的相容性较好 ,因而在相同的条件下接枝效率也更大 ;而且VA含量越大 ,越有利于接枝反应。比较不同的过氧化物引发剂BPO和DCP ,发现DCP的引发效果更好。实验结果还表明 ,在EVA进行接枝反应的同时存在着交联反应 ,引发剂DCP的用量不宜过高 ,为得到接枝率适中 ,交联度很小的接枝产物 ,还要选择合适的MAH与DCP的用量。

Peroxide acted as the initiators,maleic anhydride (MAH) grafted ethylene vinyl acetate copolymer (EVA) was prepared by melt extrusion process.The effects of different types of EVA,different kinds of initiators and their dosages,dosages of monomer and processing technology on grafting reaction were discussed emphatically.It can be proved that MAH was surely grafted onto the main chain of EVA by the methods of chemical titration and FTIR spectroscopy.Compared with polyethylene(PE) and polypropylene(PP),it was indicated that the presence of vinyl acetate (VA) group increased the polarity of EVA,which improved the compatibility of polymer matrix and grafting monomer to some extent.Under the same conditions,grafting degree of EVA-g-MAH was higher than PE and PP.The more content of VA group was,the more advantageous it was to grafting reaction.Initiator dicumyl peroxide (DCP) was more appropriate for melt grafting than benzoyl peroxide (BPO).Experiment results also showed that during grafting reaction of EVA with MAH,there was cross-linking side reaction at the same time.To avoid the side reaction of cross-linking,the content of DCP should be 0.05～0.1phr (EVA 100 phr).In order to gain grafting polymer with moderate grafting degree and low degree of cross-linking,appropriate contents of MAH and DCP should be selected.When the ratio of MAH to DCP was 20 (EVA 100 phr,DCP 0.1 phr,mass ratio),the result was best.