根据苯乙烯与丁二烯共聚时竞聚率的差异,以环己烷为溶剂,四氢呋喃为极性添加剂,用双锂活性短链引发剂一步合成了窄分布的具有无规段的S/B嵌段共聚物,采用核磁共振、红外光谱、差示扫描量热法对此聚合物进行了表征,结果表明其结构为嵌段与无规并存。透射式电镜能明显地观察到聚合物的微观相分离结构。性能测试表明该聚合物具备较好的力学性能,可视为一种热塑性弹性体,但较多无规过渡段的存在造成其永久变形较大。热熔压敏胶的测试表明,其性能符合指标要求。

According to the difference between reactivity ratio of styrene and butadiene (anionic polymeri-zation), a kind of S/B block copolymer with molecular weight distribution about 1 13 was synthesized by one step addition process with dilithium as initiator, cyclohexane as solvent and tetrahydrofuran as polar additive. S/B block copolymer was characterized by GPC, ¹H-NMR, IR, DSC. The results showed that the block and tapered structure coexisted in the product. Obvious two phase separation structure The result s showed that the block and taperedst ructure coexisted in the product . Obvious two phase separation st ructure was observed through TEM. The mechanical properties of this product showed that it had characteristics of thermoplastic elastomer , but it spermanent set was relatively high due to the existence of the tapered st ructure. The result s of hot melt pressure sensitive adhesive with this S/ B block copolymer as main component showed that the rolling ball tack , the holding
power and the peel st rength are satisfactory with the requirement .