二乙二醇单乙醚基钡/三异丁基铝/多锂体系合成高反式-1,4-聚丁二烯

以二乙二醇单乙醚基钡(简称Ba)/三异丁基铝(简称Al)/多锂(简称MLi)组成的三元引发体系制得了高反式-1,4-聚丁二烯(HTPB),考察了引发体系各组分配比及聚合温度对HTPB反式结构含量及其玻璃化转变温度(T_g)和熔点(T_m)的影响.结果表明,以MLi为引发剂,四甲基乙二胺为极性调节剂,可以得到最大臂数为3.64、平均臂数约为2.50的星形聚丁二烯;当聚合温度为50 ℃、Ba/Al/MLi(摩尔比)为1/4/4时,HTPB的反式结构摩尔分数最高,接近90%;升高聚合温度使聚丁二烯的反式结构摩尔分数下降;当HTPB的反式结构摩尔分数由69.28%增至89.90%时,其T_g上升5～10 ℃,而T_m升高幅度可达30 ℃;随着聚合温度的升高,HTPB的T_g和T_m均下降.

Synthesis of high trans-1,4- polybutadiene with barium salt of di(ethyleneglycol) ethyl ether/triisobutylaluminum/multilithium system

High trans-1,4-polybutadiene(HTPB) was prepared with barium salt of di(ethyleneglycol) ethyl ether(simplified as Ba)/triisobutylaluminum(simplified as Al)/ multilithium(simplified as MLi) initiating system. Effect of component ratio of initiating system and polymerization temperature on trans-1,4-unit content, glass transition temperature(T_g) and melting point(T_m) of HTPB were investigated. The results showed that the star polybutadiene(PB) with the maximum arm number of 3.64 and average arm number of 2.50 were obtained with self-made MLi as initiator and N,N,N′,N′-tetramethylethylenediamine as polar additive. The mole fraction of trans-1,4-unit of HTPB reached the maximum of about 90% when Ba/Al/MLi (mole ratio) was 1/4/4 at 50 ℃. The mole fraction of trans-1,4-unit of PB decreased with increasing polymerization temperature. The increase extent of T_m was 30 ℃ with the increase of trans-1,4-content from 69.28% to 89.90%, while T_g increased by 5-10 ℃. T_m and T_g decreased with increasing polymerization temperature.