立构三嵌段聚丁二烯的合成及其加氢产物的性能

Synthesis and characterization of stereotriblock polybutadiene and properties of its hydrogenated product

用α -甲基萘锂作为双官能团引发剂 ,通过丁二烯在环己烷中进行负离子聚合 ,达到一定转化率后 ,加入极性改性剂 ,继续聚合至结束 ,合成了不同嵌段比的 1,2 - 1,4 - 1,2立构三嵌段聚丁二烯 ,并用三异丁基铝及 2 -乙基己酸钴作为加氢催化剂 ,制备了氢化立构嵌段聚丁二烯。考察了不同极性改性剂及其用量和聚合温度对聚丁二烯微结构的影响 ,分析表征了立构嵌段聚丁二烯及氢化物。结果表明 ,当引发剂用量一定时 ,极性改性剂 /引发剂的摩尔比越大 ,1,2 -链节摩尔分数越高 ;当加入极性改性剂时 ,1,2 -链节摩尔分数随聚合温度的降低而增加 ,1,2 -嵌段的生成宜控制在 0℃ ;立构三嵌段聚丁二烯的相对分子质量分布很窄 ,且存在 2个玻璃化转变温度。氢化物的结晶度为 30 % ,为 (1-丁烯 -乙烯 - 1-丁烯 )三嵌段共聚物 ,呈现热塑性弹性体的行为 ;当其特性黏数大于 2 0dL·g-1,且聚1-丁烯的质量分数为 2 0 %～ 6 0 %时 ,其力学性能较好。

stereotriblock polybutadiene was synthesized by polymerization in cyclohexane to a certain conversion and polymerization was completed after adding a small amount of polar modifier.The stereotriblock copolymer was hydrogenated using cobalt 2-ethyl hexanoate and triisobutyl aluminium as the catalysts.The effects of various polar modifiers,their amount and the polymerization temperature on the microstructure of polybudatiene obtained during anionic polymerization using lithium -methyl naphthalene as the bifunctional initiator were studied.The stereoblock copolymer and hydrogenated products were characterized.The results showed that the mole fraction of 1,2-unit increased with increasing mole ratio of modifier/initiator,and with decreasing polymerization temperature when the initiator amount was not changed.The polymerization temperature of 1,2-unit was controlled at 0 ℃.The stereotriblock polybutadiene had a narrow relative molecular mass distribution and two glass transition temperatures of the copolymer. The hydrogenated product was shown to be a (1-butene-ethylene-1-butene)triblock copolymer which consisted of more than 30% crystallinity and exhibited the behavior of a thermoplastic elastomer.The mechanical property was good when the intrinstic viscosity was more than 2.0 dL·g -1 and mass fraction of 1-polybutene block was 20%～ 60%.