高枝化星形梳状丁苯嵌段共聚物的合成与性能

Synthesis and properties of star-comb dendrigraft styrene-butadiene block copolymer

采用单官能引发剂,以四氢呋喃作结构调节剂,通过活性负离子嵌段聚合法合成了高枝化星形梳状丁苯嵌段共聚物,考察了侧链的相对分子质量和结合苯乙烯含量及调节剂用量等对共聚产物的偶联效率、缺口冲击强度和拉伸性能以及微观结构等的影响。结果表明,随侧链相对分子质量的增大,共聚产物的偶联效率逐渐下降,数均分子量不大于5×10~4时的偶联效率较高;控制共聚产物的数均分子量介于(8~20)×10~4之间可使其保持较高的缺口冲击强度和较好的拉伸性能;增大侧链分子中的结合苯乙烯含量导致共聚产物的偶联效率和支化度大幅下降,而增加四氢呋喃用量则导致共聚产物中聚苯乙烯无规度和聚丁二烯的1,2-结构含量增加、偶联效率下降。

Star-comb dendrigraft styrene-butadi- ene block copolymers were synthesized by living anionic block copolymerization using monofunctional initiator and structure regulator tetrahydrofuran. The effects of number-average molecular weight and bound styrene content of branching copolymer as well as the level of structure regulator on the cou- pling efficiency, mechanical properties and micro- structure of target block copolymer were investiga- ted. The results showed that with the increase of number-average molecular weight of branching co- polymer, the coupling efficiency decreased but re- mained higher when number-average molecular weight was not more than 5× 104. By regulatingnumber-average molecular weight of block copoly- mers within the range of （8 -20） × 104, both the notch impact strength and tensile properties were kept at higher levels. The increase of bound styrene content in branching copolymers led to a significant decrease of coupling efficiency and branching degree of the block copolymers, while the increase of tetra- hydrofuran resulted in an increase of random polysty- rene and 1,2-unit polybutadiene, and a decrease of coupling efficiency.