采用乳液接枝法,分别使用两种热引发剂,制备了乙烯基三乙氧基硅烷(VTES)接枝的乳聚丁苯橡胶(ESBR),表征了接枝ESBR的结构,初步探讨了ESBR接枝机理,并与甲基丙烯酸甲酯(MMA)、苯乙烯(St)接枝ESBR得到的橡胶接枝率、单体接枝效率以及接枝橡胶的性能进行对比。结果表明,过氧化苯甲酰引发接枝按双键加成和烯丙基氢取代进行,过硫酸钾(KPS)引发接枝按双键加成进行;VTES接枝可得较高单体接枝效率;KPS引发VTES接枝可得到综合性能较好的接枝橡胶。该条件合成的SBR接枝VTES(SBR-g-VTES)与白炭黑(SiO2)共混制备的复合材料,与SBR/SiO2复合材料相比,拉伸强度提高23.72%,SiO2分布更加均匀。
Vinyltriethoxysilane(VTES) was grafted onto styrene butadiene rubber(SBR) via emulsion polymerization under two kinds of thermal initiators respectively.The structure of grafted SBR was characterized.The mechanism of emulsion grafting was investigated.The grafting ratio of SBR,grafting efficiency of VTES and properties of grafted SBR were investigated and compared with that of SBR grafted by methyl methacrylate(MMA) and styrene(St),respectively.The results indicate that the grafting efficiency of VTES is the highest of all,and the grafting reaction occurs by addition on C=C for potassium peroxydisulfate(KPS),while by removal of an allylic hydrogen atom from SBR and by addition on C=C at the same time for benzoyl peroxide(BPO).SBR grafted by VTES(SBR-g-VTES) using KPS as initiator can get good performance of grafted rubber.The results also show that the SBR-g-VTES prepared by these conditions is reinforced by silica,compared with the composite of SBR/SiO2.The tensile strength of SBR-g-VTES/SiO2 is higher.The scanning electron microscope(SEM) shows that the silica is well-distributed in SBR-g-VTES.