以新癸酸钕(Nd)/二异丁基氢化铝(Al)/一氯二乙基铝(Cl)/异戊二烯(Ip)为催化剂进行了液体异戊二烯橡胶(LIR)的合成,并采用傅里叶变换红外光谱和核磁表征了聚合物的微观结构。结果表明,聚合体系中链转移反应主要由催化剂中Al用量决定,活性中心平均转移次数与Al用量呈线性关系,催化剂中Cl用量和Ip用量对链转移反应影响不大。在优化的催化剂配制条件下,催化剂用量低至Nd/Ip=1.5×10-4时,能够合成出与进口产品分子量相当的LIR,其微观结构中只含有顺-1,4结构和3,4结构,其中顺-1,4结构含量在97.5%以上。
The liquid isoprene rubber (LIR) was synthesized with neodymium neodecanoate (Nd)/diisobutylaluminium hydride (Al)/diethylaluminum chloride (Cl)/isoprene (Ip) catalyst system.The microstructure of the polymer was characterized by FT-IR,1H-NMR and 13C-NMR spectroscopy.The results demonstrated that the chain transfer reaction in the polymerization was mainly determined by the dosage of Al in the catalyst.The average transfer number of active center was linearly related to the dosage of Al.The amount of Cl and Ip in the catalyst had little effect on the chain transfer reaction.Under the optimized catalyst preparation condition,when the catalyst dosage was as low as Nd/Ip=1.5×10-4,LIR with the same molecular weight as imported products can be synthesized.Only cis-1,4 structure and 3,4 structure can be found in the synthesized LIR.The content of cis-1,4 structure was higher than 97.5%.
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