【摘要】 以自制多官能度有机锂为引发剂,采用负离子聚合法制备了星形溶聚丁苯橡胶(SSBR),然后加入异丙醇氧锂作为解缔剂,降低体系黏度,再加入封端剂γ-氯丙基三甲氧基硅烷进行封端反应,得到端基带有三甲氧基丙基硅烷基团的改性SSBR。用核磁共振对产物进行了表征,考察了解缔剂用量、封端剂用量、封端时间以及数均分子量对SSBR封端率的影响。结果表明,解缔剂可明显降低聚合体系黏度,当SSBR的数均分子量为9.4×104、解缔剂与引发活性中心数的摩尔比为1.5、封端剂与活性中心数的摩尔比为1.5以及封端反应进行60 min时,封端率由未解缔直接封端的10.7%提高到64.1%。解缔后高封端率SSBR硫化胶与未封端和未解缔低封端率SSBR硫化胶相比,其炭黑-白炭黑填料粒子分散更均匀,且拉伸强度和300%定伸应力提高,永久变形明显降低,具有0℃损耗因子高和60℃损耗因子低的特点。更多还原

【Abstract】 Star-shaped solution polymerized styrene-butadiene rubber(SSBR) was synthesized by anionic polymerization with multifunctional lithium as initiator,and then dissociative agent lithium sec-propoxide was added to decrease the solution viscosity,after that the capping agent 3-chloropropyl trimethoxy silane was added to react with the living polymer chain ends to obtain alkoxysilane-capped star-shaped SSBR.The characterization of the products was conducted with nuclear magnetic resonance,and the effects of amounts of dissociative agent,capping agent and capping reaction time and number-average molecular weight on capping rate were investigated.The results showed that the dissociative agent could reduce the viscosity of solution of star-shaped SSBR.The capping rate raised from 10.7% for undissociated but directly capped SSBR to 64.1% when number-average molecular weight was 9.4×104,both the mole ratios of dissociative agent to initiating active center and capping agent to active center were 1.5,and end-capping reaction time was 60 min.Compared with uncapped or undissociated,low capping rate star-shaped SSBR vulcanizates,the dissociated,high capping rate star-shaped SSBR vulcanizates exhibited better carbon black-silica filler dispersion,higher tensile strength and modulus at 300%,lower permanent set,higher loss factor at 0 ℃ and lower loss factor at 60 ℃.更多还原