以2,2′-联吡啶与丙二腈为添加剂的苯乙烯活性自由基聚合的研究

Abstract

［中文文摘］研究了稳定自由基存在下苯乙烯的活性聚合 .发现在 2 ,2′ 联吡啶的存在下 ,苯乙烯聚合的分子量控制效果提高 ,分子量可控 ,分子量分布较窄 .在与丙二腈共同作用时 ,可在 4h内达到 85 %的转化率 ,分子量分布在 1 5以下 ,分子量控制误差在 2 0 %以下 .设计分子量在 1× 10 4 ～ 9× 10 4 的范围内 ,实测分子量和理论分子量相近 .［英文文摘］The living free radical polymerization of styrene was studied with benzoyl peroxide as the initiator in the presence of TEMPO (2,2,6,6 tetramethylpiperidinyl 1 oxy).It was found that styrene polymerization was distinctly accelerated by means of using malononitrile (MN) as additive.The purpose of this paper is to explore the effect of MN/bpy on the control of molecular weight.These mixture additives were able to control the polymerization of styrene to high conversion (85%) in 4 hours, and samples of molecular weight from 1 ×104 to 9 ×104 and with polydispersities of 1. 15 to 1. 4 were readily obtained. In comparison with the polymerization without any additives , these systems represented a dramatic improvement in the ability to control the molecular weight . The molecular weight of the polymer gradually increased with time , while the narrow molecular weight distribution remained unchanged. The molecular weight evolved in a nearly linear fashion with increasing conversion.Using a 1∶112 molar mixture of BPO and TEMPO with [ Bpy ]P[ TEMPO ] = 2P1 , [MN ]P[ TEMPO ] = 215 , the conversion of the polymerization at 135 ℃reached 85% in 4 hours , and the polydispersity was below 115 , and the difference between the theoretical molecular weight and the experimental molecular weight was controlled below 20%.