聚(N-异丙基丙烯酰胺)微凝胶的流变性能研究

摘要

首先采用无皂乳液聚合法成功制备出粒径均匀的聚N-异丙基丙烯酰胺(PNIPAM)微凝胶,利用动态光散射法(DLS)测得微凝胶的粒径随温度的升高而下降,结果表明:PNIPAM微凝胶具有明显的温度敏感性.利用旋转流变仪对微凝胶分散液的稳态和动态粘弹性进行了研究,结果表明:当温度低于体积相转变温度(VTPP)时,微凝胶呈现出剪切变稀的特性;应力、应变保持不变,随着温度的升高及温度不变,随着频率的增加微凝胶都由液态变成了粘弹性固体,这可能是由于出现了三维逾渗网络结构造成的.%At first poly(N-isopropyl acrylamide) microgel with uniform particle size was prepared by soap-free emulsion polymerization,the method of dynamic light scattering (DLS) was used to measure the particle size change of the microgel with temperature.The results show that the PNIPAM microgel has obvious temperature sensitivity.The rotational rheometer was used to study steady-state and dynamic viscoelasticity of the micro gel dispersion liquid.The results show that when the temperature is lower than the volume phase transition temperature (VTPP),the shear thinning characteristic of the microgel appears;under constant stress and strain,with the increase of temperature and frequency,the micro gel can be converted into viscoelastic solid from liquid.