PU/纳米SiO2溶胶杂化材料的前端聚合研究

前端聚合(FP)是通过在单体前端区域引发增长聚合将单体合成为聚合物的一种不同于传统的反应模式．它是一种通过局部反应区域在聚合物单体中的移动而将聚合物单体转变为聚合物的一种反应模式，主要运用在放热反应中，在反应初始阶段进行短时间的加热，然后停止加热，借助放热反应的热自催化完成单体的聚合。根据反应机理的不同，

STUDY ON FRONTAL POLYMERIZATION OF POLYURETHANE/NANOSILICA SOL HYBRIDS

Frontal polymerization (FP) is a mode of converting monomers into polymers via a localized reaction zone that propagates through the reaction system.The three reactants,polyether,toluene 2,4-diisocyanate and 1,4-butanediol and the catalyst (stannous caprylate) were mixed together at room temperature along with nanosilica sol and dimethylbenzene (as the solvent).After the thermal ignition at one end of the tubular reactor and subsequent front formation,no further energy was required for polymerization to occur.The thermal front self-propagated throughout the vessel.The effect of different molecular weights of polyether and different concentration of catalyst on frontal polymerization were investigated,along with a comparison of frontal polymerization with batch polymerization.FT-IR,TEM and TGA were employed to characterize the polyurethane (PU) hybrids.The obtained polymer materials by FP displayed similar features compared with those obtained by batch polymerization (BP).The reaction time of FP is quite less than that of BP during preparing the PU hybrids.Nanosilica sol can be well dispersed in the polyurethane hybrid matrix even though no any stirring occurs during the FP process.