反应挤出法合成S/B多嵌段共聚物的研究

STUDIES ON S/B MULTI-BLOCK COPOLYMER POLYMERIZED BY REACTIVE EXTRUSION

在阴离子引发体系下 ,以双螺杆挤出机为反应器 ,采用丁二烯、苯乙烯混和单体加料方式 ,本体法一步合成了S B多嵌段共聚物 .考察了螺杆转速、进料速率以及不同丁苯配比对反应挤出合成PS及S B嵌段共聚物聚合转化率的影响 .用1 H NMR、IR、DMA、TEM等方法对S B嵌段共聚物进行了表征 ,结果表明共聚物由多个微小的丁二烯嵌段和少量无规段组成 .当丁二烯含量少至 15 %左右时 ,其嵌段可回缩成球状 ,粒径大约在 30～ 5 0nm .该材料的韧性随着共聚物中丁二烯含量的增加而逐渐提高 。

A kind of styrene-butadiene (S/B) multi-block copolymer was bulk-polymerized in a twin-screw extruder with the anion initiators and mixed S/B monomers. The effects of screw rotational speed, feed rate of monomers and St content on the conversion of styrene and S/B mixture were researched. S/B block copolymer was characterized by H-1-NMR, IR, DMA. It is shown that a lot of short polybutadiene blocks and a little random structure coexist in the copolymer. It also can be seen in TEM photographs that the polybutadiene blocks, while being less than 15% in whole composition, can retract into the ball shape 30 similar to 50 nm in diameter. On the other hand, the toughness especially the elongation at break, of the copolymer grows stronger with the increase of butadiene content.