高苯乙烯溶聚丁苯橡胶的制备、结构与性能

Synthesis,structure and properties of solution polymerized butadiene-styrene rubber with high bound styrene content

采用负离子聚合法,以环己烷为溶剂、正丁基锂为引发剂、四氢呋喃为极性调节剂、叔戊醇钾为无规化剂合成了结合苯乙烯质量分数为40%、乙烯基摩尔分数为35%~40%且苯乙烯结构单元在大分子链中均匀分布的溶聚丁苯橡胶,并考察了其性能。结果表明,四氢呋喃对乙烯基含量的调节起主要作用,而叔戊醇钾对其无影响;叔戊醇钾主要调节苯乙烯结构单元在大分子链中无规分布的均匀性,而四氢呋喃对其基本无影响。当四氢呋喃与正丁基锂的摩尔比为50、叔戊醇钾与正丁基锂的摩尔比为15.33×10^(-3)时,在大分子链的增长过程中结合苯乙烯量都保持在设计值附近,表明苯乙烯结构单元在大分子链中基本为均匀无规分布。随着相对分子质量的增大,除300%定伸应力有所增加之外,胶料的其他力学性能及磨耗的变化不大,说明将高苯乙烯溶聚丁苯橡胶的数均分子量控制在(20~40)×10~4均可;随着苯乙烯结构单元无规分布均匀度的提高,胶料的拉伸强度、扯断伸长率、压缩温升等的变化不大,硬度、300%定伸应力、磨耗及滚动阻力等有所下降,抗湿滑性能和炭黑分散性有所改善。

A solution polymerized styrene-butadi- ene rubber in which the mass fraction of bound sty- rene was 40%, the mole fraction of vinyl was 35% -40% and the distribution of styrene units in macromolecular chain was random and uniform was synthesized with n-BuLl as initiator, cyclohexane as solvent, tetrahydrofuran as regulator and potassium tert-pentylate （t-PeOK） as random agent, and the properties of obtained polymer were studied. The re- suits showed that tetrahydrofuran played a major role in regulating vinyl content, but t-PeOK had no effect on vinyl content, t-PeOK improved the uniformity of random distribution of styrene unit significantly, on the contrary, tetrahydrofuran had little effect on it. When the tetrahydrofuran/n-BuLi （mole ratio） and t-PeOK/n-BuLi（mole ratio） was 50 and 15.33 × 10-3 respectively, the content of bound styrene was close to its designed value in the whole propagation process of polymer, indicating that styrene unit in the rubber molecular chain were distributed uniform- ly and randomly. The mechanical properties and ab- rasion of the rubber had no obvious change with the increase of relative molecular mass except the en- hanced modulus at 300%, demonstrating that the relative molecular mass of solution polymerized sty- rene-butadiene rubber with high bound styrene con- tent could be ranged between （20 -40） × 104; with the improvement of random distribution uniformity of styrene unit, the tensile strength, elongation at break and compression temperature rise of the rubber had no evident change, the modulus at 300%, hardness, abrasion and roiling resistance decreased, and the wet skid resistance and the dispersion of car- bon black were improved.