潜伏性引发剂单体合成长链超支化聚苯乙烯

Synthesis of Long Chain Hyperbranched Polystyrene by Latent Inimer

首先设计合成出新型潜伏性引发剂单体呋喃N-[4-(2溴异丁酰氧基)苯基]马来酰亚胺(FBiBPMI),然后90℃下用其引发苯乙烯(St)发生原子转移自由基聚合(ATRP)合成长链超支化聚苯乙烯。采用气相色谱、高效液相色谱、核磁共振氢谱、三检测体积排除色谱和扩散光谱分别表征了引发剂单体的纯度和结构,测定了苯乙烯的转化率、聚合物相对分子质量及其分布、特性黏度、均方回转半径、支化形态和聚合物溶液微流变行为。实验结果表明,成功合成了呋喃N-[4-(2溴异丁酰氧基)苯基]马来酰亚胺(FBiBPMI)。由于FBiBPMI上马来酰亚胺双键被呋喃保护,反应前期初级链大多为线型结构,随着反应进行,链端发生rD-A反应,呋喃结构逐步脱除,马来酰亚胺双键缓慢消耗,显现出来的马来酰亚胺双键与初级链、苯乙烯发生共聚反应形成支化结构。反应前期没有明显的成核过程,聚合物相对分子质量随转化率逐步升高,反应后期分子链间偶合更加明显,相对分子质量快速增加,最终形成无规的长链超支化聚苯乙烯。

In this paper,furan N-[4-(2-bromoisobutyryloxy)phenyl]maleimide(FBiBPMI)was designed and synthesized as novel latent inimer.At 90℃,styrene underwent atom transfer radical polymerization(ATRP)with FBiBPMI to synthesize long chain hyperbranched polystyrene.The purity and structure of the inimer were characterized by high performance liquid chromatography(HPLC)and nuclear magnetic resonance spectroscopy(NMR).The molecular weight and distribution,intrinsic viscosity of the polymer were determined by three-detection gel permeation chromatography(TD-SEC).Microfluidic behavior of the polymer solution was determined by diffusion wave spectrometer(DWS).The results show that furan N-[4-(2-bromoisobutyryloxy)phenyl]maleimide(FBiBPMI)was carried out successfully.Since the maleimide double bonds of FBiBPMI were protected by furan,the primary chains in the pre-reaction period were mostly linear.As the reaction proceeding,there was rD-A reaction at the end of chain.The furan structure was gradually removed,and the maleimide double bonds were consumed gradually.The appeared maleimide double bonds copolymerized with the primary chains and styrene,forming long chain hyperbranched PS.There was no obvious core formation in the early stage of the reaction and the molecular weight of the polymer increased with the conversion of St.The coupling between the molecular chains was more obvious at the late stage of the reaction,and the molecular weight increased rapidly.Finally,a random long-chain hyperbranched PS was formed.