PDEAm接枝PAN/PSt温敏性聚合物微球的制备及表征

Preparation and characterization of poly(N,N-diethyl acrylamide)-g-polyacrylonitrile/polystyrene microspheres with thermosensitivity

利用链转移自由基聚合制得了端羟基化的聚N,N-二乙基丙烯酰胺(PDEAm-OH)低聚物,进而与丙烯酰氯缩合得到温敏性的PDEAm大分子单体,利用FT-IR、1 H NMR和UV对该大分子单体的结构、末端双键含量和温敏性进行了表征,测得该大分子单体的最低临界溶解温度(LCST)为36.4℃。将PDEAm大分子单体与丙烯腈(AN)、苯乙烯(St)在乙醇/水混合介质中进行三元分散共聚,制得了PDEAm接枝聚丙烯腈/聚苯乙烯(PDEAm-g-PAN/PSt)聚合物微球,由扫描电子显微镜SEM观察到的结果表明,聚合物微球表面具有明显的突起形态,其粒径均一,分散稳定性好,改变聚合反应条件可控制所得聚合物微球的形貌和粒径。该聚合物微球的粒径随温度的升高而减小,表明其具有温度敏感性。

Poly（N,N-diethylacrylamide） with a terminal hydroxyl end group（PDEAm-OH） was synthesized by radical polymerization in the presence of 2-mercaptoethanol（ME）.Thermosensitive poly（N,N-diethylacrylamide）（PDEAm） macromonomer was prepared by condensation reaction of PDEAm-OH with acryloyl chloride.The macromonomer was characterized by FT-IR,1H NMR,UV-spectrophotometer,which has a lower critical solution temperature（LCST） of 36.4℃ in aqueous media.Then PDEAm grafted poly（acrylonitrile/styrene）（PDEAm-g-PAN/PSt） polymeric microspheres can be prepared by dispersion copolymerization of PDEAm macromonomer with AN/St in ethanol/water mixed solvents.The morphology and the average size of the polymeric microspheres can be controlled by changing the polymerization conditions.Scanning electron microscopy（SEM） images and particle size analysis under different temperature show that the microspheres have monodispersibility and thermosensitivity.