立构嵌段聚丁二烯的研制 Ⅵ.立构三嵌段聚丁二烯结构与性能

DEVELOPMENT OF STEREOBLOCK POLYBUTADIENE Ⅵ.STRUCTURE AND PROPERTIES OF STEREOTRIBLOCK POLYBUTADIENE

采用高分子设计,以α-甲基萘锂为引发剂,环己烷为溶剂,二哌啶乙烷为调节剂,合成了立构三嵌段1,2-1,4-1,2-聚丁二烯(PB)。结果表明:当该聚合物的1,2-结构摩尔分数为53%～84%。1,4-结构摩尔分数为20%～52%时,试样具有2个 T_g;相对分子质量越高,越容易产生微观相分离;随着剪切速率γ的增大,流变指数和表观粘度均下降,非牛顿性增强。当为316.2 s^(-1)时,立构三嵌段1,2-1,4-1,2-PB 的表观活化能介于1,4-PB 与1,2-PB 之间,三者依次为4.89,4.31,5.98 kJ/mol;屈服强度随着1,4-结构摩尔分数的增加而下降。

The stereotriblock 1,2-1,4-1,2 polybu- tadiene(PB)was synthesized by polymer de- sign method with lithium α-methyl naph- thalene as initiator,dipiperidinoethane as modifier and cyclohexane as solvent.The ef- fects of the 1,2- content,block ratio and rel- ative molecular mass of PB on the T_g,mor- phology structure,rheological behavior and yield strength of the polymers were studied. The results showed that the polymer had two T_g only when the 1,2-content was in the range of 53%～84%.The rheological index and apparent viscosity decreased with the in- crease of shear rate.The apparent activation energy and yield strength of tribloek PB were between 1,2-PB and 1,4-PB at same shear rate.