烯烃复分解法制备高乙烯基聚丁二烯离聚体及其结构和性能

Preparation of high vinyl polybutadiene ionomer by olefin metathesis and its structure and properties

以甲基丙烯酸乙酯(EMA)为改性单体,采用交叉烯烃复分解法对高乙烯基聚丁二烯(HVBR)酯基官能化改性。研究了烯烃复分解催化剂种类和用量、EMA用量、反应条件等对改性HVBR的接枝率和黏均相对分子质量(M_(v))的影响。研究表明,使用Hoveyda-Grubbs二代催化剂,催化剂与单体的质量比为1.5×10^(-4),EMA与HVBR的质量比为1时,产物接枝率最高。烯烃复分解反应优先与HVBR的侧乙烯基双键反应。采用溶液法酯基官能化改性后的HVBR与NaOH反应可制备HVBR羧酸钠离聚体。离聚体的拉伸强度与HVBR相当,扯断伸长率提高了50%,撕裂强度提高了30%,力学性能得到显著改善。硫化胶的动态机械性能分析仪(DMA)数据显示,HVBR羧酸型离聚体的阻尼温域均变宽,提高了20%以上,是一种良好的宽温域阻尼材料;离聚体具有高抗湿滑和低滚阻,可以用于绿色轮胎制造。

The ester group of high vinyl polybutadiene(HVBR)was functionalized and modified by cross-olefin metathesis method,and ethyl methacrylate(EMA)was used as the modified monomer.The conditions affecting the grafting rate and molecular weight of modified HVBR were studied,including the type and amount of olefins redecomposition catalyst,the amount of EMA,reaction conditions,etc.It is clear that the highest reactivity for the grafting reaction is the second-generation Hoveyda-Grubbs catalyst.And when the mass ratio of catalyst to monomer is 1.5×10^(-4) and the mass ratio of EMA to HVBR is 1,the grafting rate of the product is the highest.The pendant vinyl double bond of HVBR reacts preferentially.Sodium HVBR carboxylate ionomer was prepared by solution method,in which the ester group functionalized modified HVBR reacted with NaOH.The tensile strength of the ionomer was comparable to that of HVBR,and the elongation at break was increased by 50%,and the tear strength was increased by 30%,and the mechanical properties were significantly improved.The DMA data of HVBR carboxylic acid ionomer showed that the damping temperature range of ionomer was widened by more than 20%,which was a good wide temperature range damping material.And ionomer had higher wet skid resistance and lower rolling resistance,which could be used in green tire manufacturing.