反应挤出阴离子本体聚合制备苯乙烯类合成橡胶

Anionic Bulk Polymerization of Styrene Rubbers by Reactive Extrusion

在同向啮合双螺杆挤出机中,以正丁基锂为引发剂,成功合成了苯乙烯(St)/异戊二烯(Ip)/丁二烯(Bd)三元集成橡胶SIBR及苯乙烯/异戊二烯/苯乙烯热塑性橡胶(SIS)。通过对螺筒温度以及二烯烃单体加料位置的精确控制,成功抑制了聚合过程中凝胶的生成。核磁共振氢谱、凝胶渗透色谱及动态力学分析证明,由St/Ip/Bd混合单体制得一种多嵌段共聚物,而与正丁基锂等摩尔比引入的四甲基乙二胺(TMEDA)使得该共聚物的无规化程度得到明显提高。另由St和Ip单体两次顺序加料偶联法制得一种具有较规整的SIS三嵌段共聚物,该聚合物的相对分子质量及其分布分别为7.9×104和1.8。拉伸性能测试表明,2种共聚物的拉伸强度均在15 MPa以上。

Three-element integrated rubber SIBR,the copolymer of styrene( St) /isoprene( Ip) /butadiene( Bd),and St /Ip /St triblock thermoplastic elastomer SIS were bulk-anionic polymerized successfully by co-rotating intermeshing twin screw extruder as reactor and n-butyllithium as initiator. The gel phenomenon during the polymerization was inhibited effectually by precise control of the barrel temperature and the feeding position at barrel of the diene. The analyses of1H-NMR,GPC and DMA show that three-element integrated rubber SIBR could be polymerized by the feeding method using the mixture of St,Ip and Bd. Its random degree could be increased observably while tetramethylethylenediamine was introduced into the system as the same mole number as n-butyllithium. On the other hand,a regularized triblock thermoplastic elastomer SIS could be polymerized by the sequentially-feeding method from St to Ip,and the coupling reaction at the end of polymerization. The molecular weight and molecular weight distribution of that polymer are 7. 9 × 104 and 1. 8 respectively. The stretch analyses show that the tensile strength of both kinds of copolymers is above 15 MPa.