聚丙烯表面接枝PNIPAAm膜Ⅰ.光接枝反应和表面形态结构研究

以氧杂蒽酮或二苯甲酮为引发剂 ,通过紫外光引发表面接枝聚合的方法在聚丙烯薄膜表面引入了具有温度敏感特性的聚异丙基丙烯酰胺 (PNIPAAm)接枝聚合物层 .提高紫外光强度和接枝反应温度均有利于接枝率增大 ,而单体浓度对接枝率的影响存在最佳值 ,为 0 1 8mol L .在引发剂预浸渍引发接枝和休眠基引发接枝这两种方式中 ,后者能够实现更高的接枝率 .红外光谱 (FTIR)、X射线光电子能谱化学分析 (ESCA)和扫描电子显微镜 (SEM)等对接枝层组成的表征结果证实了接枝层的存在 .在不同温度下 ,接枝膜的FTIR谱图中酰胺I带和酰胺II带特征吸收峰发生位移 ,表明它具有温度敏感特性 .同时 ,SEM研究发现由于接枝膜的温度敏感特性而导致的球状表面形态结构

PREPARATION AND SURFACE MORPHOLOGY OF PNIPAAm-GRAFTED LAYERS ON POLYPROPYLENE FILMS

N-Isopropylacrylamide (NIPAAm) was introduced onto the surface of polypropylene (PP) films to form a layer of poly(N-isopropylacrylamide) (PNIPAAm) by UV-induced surface photograft polymerization reaction.Improvement on UV intensity and reaction temperature favored the increase of the grafting yield,yet it went through a maximum as monomer concentration was increased.Two photograft techniques,the xanthen-9-one pre-dipping method and dormant radical method,were tried and higher grafting yields were achieved by the latter.The existence of PNIPAAm grafted polymer layer was confirmed by FTIR,ESCA and SEM measurements.The acrylamide band I and II in FTIR spectra of the grafted polymer shifted as the temperature changed,which revealed the temperature sensitivity of the grafted films.Moreover,a special sphere-like surface morphology of the NIPAAm layers due to the temperature-responsive behaviors was observed by SEM.