双锂引发剂一步法合成S/B嵌段共聚物的研究

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。

Study on synthesis of S/B block copolymer by one-step addition process with dilithium initiator

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 was observed through TEM. The mechanical properties of this product showed that it had characteristics of thermoplastic elastomer, but its permanent set was relatively high due to the existence of the tapered structure.The results 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 strength are satisfactory with the requirement.