SYNTHESIS AND CHARACTERIZATION OF COMB-SHAPED POLYBUTADIENES

Polybutadiene (PB) was chlorinated with t-BuOCl without chain crosslinking and degradation togive chlorinated polybutadiene (Cl--PB) with active allylic chlorine atoms on the backbone. Comb-shaped PB was prepared by coupling of Cl--PB with "living" PB anions in a mixed solvent of cyc-lohexane and tetrahydrofuran. Characterization by GPC and osmometry showed that purifiedproducts were welldefined comb-shaped PB composed of low polydispersity backbone chain andrandomly distributed grafts of uniform length. The averagr number of branches could be variedin a wide range to meet the needs of structure-properties relationship studies.     

梳状聚丁二烯的合成及表征

以次氯酸叔丁酯为氯化剂,在无降解及交联情况下,向阴离子聚合的聚丁二烯主干引入活泼氯。氯化聚丁二烯与活性聚丁二烯阴离子(PB~(?))偶合得到支链沿主干无规分布的梳状聚丁二烯。降低偶合温度,提高[PB~(?)]/[Cl]比值及加入极性溶剂四氢呋喃,均有利于提高偶合接枝效率。渗透压法及GPC法的表征结果表明,沉淀分级净化产物为具有窄分子量分布主干及支链、结构确定的梳状聚丁二烯。其平均支链数可在较大范围内改变。