窄分布低乙烯基线型液体聚丁二烯的环氧化反应

采用负离子聚合法设计合成了分子量分布(MWD)窄、乙烯基含量低的线型液体聚丁二烯(NDLPB),然后用过氧甲酸原位法制备了不同环氧度的环氧化线型液体聚丁二烯(ENDLPB),并以其为偶联剂合成了梳状聚丁二烯,通过核磁共振法对ENDLPB的环氧度和结构进行了表征,考察了ENDLPB环氧度的影响因素.结果表明,随着ENDLPB环氧度的增加,环氧基特征峰逐渐增强,顺式-1,4-结构和反式-1,4-结构含量减小,1,2-结构含量不变;随着NDLPB数均分子量(~￣M_n)的增加,ENDLPB的环氧度减小,且~￣M_n略有增大,MWD约为1.08;以~￣M_n为2 450、MWD为1.07的NDLPB为反应物,在H_2O_2/NDLPB(摩尔比)为0.5、甲酸/NDLPB(摩尔比)为 0.4、反应温度为50 ℃的条件下反应2 h,可获得环氧度约为33%的ENDLPB,且实验的重复性良好;改变ENDLPB用量可获得不同偶联度的梳状聚丁二烯.

Epoxidation of low vinyl linear liquid polybutadiene with narrow molecular weight distribution

The linear liquid polybutadiene with narrow molecular weight distribution(MWD)and low vinyl content (NDLPB)were synthesized by anionic polymerization. The epoxidized liquid polybutadiene(ENDLPB) with different epoxidation degree were prepared by formic acid-hydrogen peroxide in-situ method and used as coupling agent for comb polybutadiene. The epoxidation degree and microstructure of ENDLPB were characterized by nuclear magnetic resonance. The effect factors on epoxidation degree of ENDLPB were investigated. The results showed that with the increase of epoxidation degree, the characteristic peaks of epoxy group gradually increased, the contents of cis-1,4-uint and trans-1,4-unit decreased, and the 1,2-unit content almost had no change. With increasing ~￣M_n of NDLPB, epoxidation degree of ENDLPB decreased,~￣M_n of ENDLPB slightly increased, and the MWD of ENDLPB was around 1.08. With NDLPB of ~￣M_n of 2 450,MWD of 1.07 as the reactants, under the conditions of H_2O_2/NDLPB(mole ratio) 0.5, formic acid/NDLPB(mole ratio) 0.4, reaction at 50 ℃ for 2 h, the epoxidation degree of ENDLPB was about 33%, and experimental repeatability was good. The comb polybutadienes with different coupling degree were synthesized by changing amount of ENDLPB .