氢化钠/三异丁基铝体系合成星形聚苯乙烯的研究

Study on synthesis of star polystyrene with sodium hydride/triisobutylaluminum system

采用阻滞阴离子调控技术,通过"先核后臂"法以NaH/三异丁基铝(i-Bu3Al)与苯乙烯、二乙烯基苯(DVB)反应制备的多钠引发剂为核,乙苯为溶剂,合成了星形聚苯乙烯(PS)(cs-PS);通过"先臂后核"法,以NaH/i-Bu3Al直接引发苯乙烯聚合,DVB为偶联剂,也合成了星形聚苯乙烯(as-PS)。采用气相色谱测定了聚苯乙烯钠与DVB中四种组分在100℃下的聚合反应速率,并用凝胶渗透色谱分析测试了聚合物的分子参数及平均臂数。结果表明:聚苯乙烯钠与DVB中四种组分的聚合反应速率与单体浓度呈假一级动力学关系;随着n(DVB)/n(NaH)的增加,cs-PS和as-PS的相对分子质量均逐渐增加,相对分子量分布均变宽,平均臂数也随之增大。

Star polystyrene（cs-PS） was synthesized in a ＂core-first＂ mode via retarded anionic polymerization with taking multi-sodium prepared from sodium hydride（NaH）/triisobutylaluminum（i-Bu3Al）,styrene and diviny-lbenzene（DVB） as initiator core,and ethylbenzene as solvent.Star polystyrene（as-PS） was also synthesized in an ＂arm-first＂ mode with NaH/i-Bu3Al as initiator and DVB as coupling agent.The polymerization rates of sodium polystyrene（PSNa） with four kinds of component of DVB at 100 ℃ were determined by gas chromatography.The molecular parameters and average arm number were measured with gel permeation chromatography（GPC）.The results show that the polymerization rates of sodium polystyrene with the components of DVB and the monomer concentration conform to pseudo-first-order kinetics relationship.As the molar ratio of DVB to NaH increases,the relative molecular mass of cs-PS and as-PS is raised gradually and the relative molecular mass distribution is widened,followed by the increase in average arm number.