1,3-戊二烯/苯乙烯阳离子共聚合反应

CATIONIC COPOLYMERIZATION OF 1,3PENTADIENE WITH STYRENE

本文研究了以甲苯为溶剂，ＡｌＣｌ３和ＢＦ３·ＯＥｔ２为引发剂，１，３－戊二烯（ＰＤ）与苯乙烯（Ｓｔ）的阳离子共聚合反应，并用红外光谱测定聚合物的微观结构。由共聚单体ＰＤ和Ｓｔ加入顺序的不同可生成无规共聚物Ｐ（ＰＤ－ｃｏ－Ｓｔ）和接枝共聚物Ｐ（ＰＤ－ｇ－Ｓｔ）和Ｐ（Ｓｔ－ｇ－ＰＤ）。无论是由ＡｌＣｌ３引发聚合反应，还是由ＢＦ３·ＯＥｔ２引发聚合反应，Ｓｔ上的碳阳离子的活性都高于ＰＤ上碳阳离子的活性。由ＡｌＣｌ３首先引发ＰＤ进行聚合反应，结束后再引入Ｓｔ时，聚合体系不能引发Ｓｔ聚合反应；相反ＡｌＣｌ３首先引发Ｓｔ聚合后的体系能继续引发ＰＤ的聚合反应。ＢＦ３·ＯＥｔ２无论先引发Ｓｔ或是ＰＤ，都能在聚合反应完成后接着引发另一单体而生成接枝共聚物Ｐ（ＰＤ－ｇ－Ｓｔ）和Ｐ（Ｓｔ－ｇ－ＰＤ）。二苯醚与烯丙基氯的加入，提高了碳阳离子的稳定性，增加了聚合物的分子量，但降低了碳阳离子的活性，使得聚合反应的产率降低。

The cationic copolymerization of 1,3pentadiene (PD) with styrene (St) initiated by AlCl3 and BF3OEt2 was carried out in toluene.The microstructure of the copolymer was characterized by IR spectrometer.The random copolymer P(PDcoSt),graft copolymers P(PDgSt) and P(StgPD) result from three corresponding monomer addition procedure.The carbocation activity of PSt,whether initiated by AlCl3 or by BF3OEt2,is higher than that of PPD.After the polymerization of PD initiated by AlCl3 was completed,St can not be initiated by the polymerization system when St was introduced into the system.However,PD can be initiated by the polymerization system in which St has been first initiated by AlCl3,and the graft copolymer P(StgPD) has been produced.While BF3OEt2 is used as initiator,both polymerization systems of St and PD can initiate the polymerization of the other comonomer.Therefore,the graft copolymers P(PDgSt) and P(StgPD) could be produced through chain transfer processes.The introduction of diphenyl ether and