摘要
采用紫外光谱、红外光谱研究了聚苯乙烯(PS)交联白球固载SnCl_4所得引发剂的结构及引发聚合机理。结果表明,给电子配位体丁酮中的羰基参与了络合,并随聚合反应时间的延长,络合作用增强。引发剂不含丁酮,则不具备引发活性。引发剂是一种配位化合物,单体在其表面以插入方式聚合,活性中心是离域阳离子大共轭体系,聚合反应可在常温、不隔绝水和空气的条件下进行,具有络合聚合特征。
As a new type of initiator , SnCl4, absorbed onto the surface of PS and coordinated with CH3COC2H5 (MEK), can initiate the polymerization of isobutyl vinyl ether (IBVE)or α-methyl styrene (α-MS)at room temperature in a moderate enviornmant disregarding the presence of water and air . The process is proved to be a cationic polymerization process by using diphenyl - picryl hydrazide (DPPH) inhibitor (Figure 1).Ultraviolet spectroscopy study on the polymer-supported initiator shows that the carbonyl group of MEK joins the coordination , and the coordination is strengthened as polymerization propagates .The initiator system doesn 't possess reactivity without MEK .Ultraviolet study on the model compound of PS-SnCl4-MEK initiator system is shown in Figure 2. The coordination of SnCl4 with phenyl ring is indicatedby the absorption band at 290 - 300 nm . The coordination of SnCl4 with MEK is indicated by the band at 320 nm which is the MEK carbonyl absorption with red shift of 33 nm . All of these prove the existence of PS-SnCl4-MEK coordination complex . Infrared study also shows that the absorption band of MEK carbonyl stretch vibration shifts from 1717.1 cm-1 to 1648.5cm-1 as a result of SnCl4-MEK coordination .The polymerization mechanism of IBVE and α-MS initiated by the PS-SnCl4-MEK is given below :The active center is a cation complex formed in a conjugated system . Monomers are polymerized at the surface of initiator by insertion exhibiting the characteristics ofcationic coordination polymerization .
出处
《合成橡胶工业》
CAS
CSCD
北大核心
1992年第1期33-37,共5页
China Synthetic Rubber Industry
关键词
聚苯乙烯
四氯化锡
引发剂
位聚合
polystyrene - tin tetrachloride initiator
cationic coordination polymerization
reaction mecha- nism
isobutyl vinyl ether
α-methyl styrene
