改性低分子量聚异戊二烯橡胶的合成与应用

Synthesis and Application of Modified Low Molecular Weight Polyisoprene

采用阴离子溶液聚合法合成了低分子量3,4-聚异戊二烯(LPI),并对其进行改性,制备了硅氧烷改性的低分子量3,4-聚异戊二烯(MLPI),将其应用于白炭黑补强的溶聚丁苯橡胶(SSBR)复合材料,探究了端基改性物LPI-丙基甲基二甲氧基硅烷(LPI-CMDS)、LPI-丙基三甲氧基硅烷(LPI-CTMS)、LPI-丙基三乙氧基硅烷(LPICTES)和接枝改性物3-巯丙基三乙氧基硅烷接枝改性LPI(LPI-g-MTS)对SSBR复合材料中白炭黑的分散以及硫化胶性能的影响.混炼胶的应变扫描和结合胶含量分析结果表明,MLPI增强了填料与聚合物之间的相互作用,改善了白炭黑在复合材料中的分散,其中LPI-g-MTS因活性位点多,效果最佳;与填充LPI的复合材料相比,硫化胶的物理机械性能,尤其是填充LPI-g-MTS后硫化胶的300%定伸应力和拉伸强度分别提升了89.66%和27.15%,这为改善白炭黑在非极性橡胶中的分散提供了一条新途径.

Low molecular weight 3,4-polyisoprene(LPI)was prepared by anionic solution polymerization and then it was modified to prepare siloxane modified functionalized low molecular weight 3,4-polyisoprene(MLPI),including three end group-modified materials,LPI-propyl methyldimethoxysilane(LPI-CMDS),LPI-propyl trimethoxysilane(LPI-CTMS),LPI-propyl trimethoxysilane(LPI-CTES)and one graft-modified material,3-mercaptopropyl triethoxy silane graft modification LPI(LPI-g-MTS).The influences of LPI and MLPI on dispersion of silica and properties of solution polymerized styrene butadiene rubber(SSBR)composites were studied.Improvement of interaction between the filler and the polymer and dispersion of silica in the composites was domenstrated by strain scanning and bound rubber content results.Due to the more active sites,LPI-g-MTS had the best effect.Compared to the unmodified LPI filled composite,the physical and mechanical properties of the LPI-g-MTS filled composites increased,especially the modulus at 300%elongation increased by 89.66%and the tensile strength increased by 27.15%.This work provides a new method to improve the dispersion of silica in rubber/silica composites.