【作者】 郭辉； 查刘生；

【Author】 Hui GUO;Liusheng ZHA;College of Materials Science and Engineering, Donghua University;

【机构】 东华大学材料科学与工程学院；

【摘要】 采用旋转流变仪测试不同浓度(1.5 wt%、2.5 wt%、3.5wt%)由交联聚(N-异丙基丙烯酰胺)(PNIPAM)和交联聚丙烯酸(PAA)形成的、具有互穿聚合物网络结构(IPN)的pH/温度双重敏感性微凝胶(PNIPAM/PAAIPN微凝胶)水分散液的动态流变性能在pH值分别为3或7时随温度(20℃～40℃)的变化关系。结果发现,当pH值为3时,分散液的损耗模量(G")始终大于储能模量(G’),其粘弹性在任何浓度和温度下都以粘性为主。当pH值为7时,分散液的G’在温度低于32℃时均小于G",且都随温度升高呈缓慢下降的趋势;当温度超过32℃时,分散液的G’和G"均随温度升高而急剧上升,并且G’上升的速度大于G"。超过某一临界温度Tc后,分散液的G’反过来大于G",其粘弹性由以粘性为主转变为以弹性为主。另外,还发现Tc随分散液浓度升高而降低。更多还原

【Abstract】 The temperature dependence on the dynamic rheological property of the aqueous dispersion of the pH/temperature dually sensitive microgels with interpenetrating polymer network(IPN) structure(PNIPAM/PAA IPN microgles), composed of crosslinked poly(N-isopropylacrylamide)(PNIPAM) and crosslinked poly(acrylic acid)(PAA), was investigated by rotation viscometer. When the pH value of the aqueous dispersion was 3, its loss modulus(G’’) of the dispersions was always larger than its storage moduli(G’) over the entire measured temperature range, indicating its viscoelastic property is dominated by viscosity. When the pH value of the dispersion was 7, its G’ was smaller than its G’’ at the temperatures below 32℃, and both of them were lowered with the temperature rising. As the temperature rised and exceeded 32℃, its G’ and G" were notably increased, and G’ increased more rapidly than G". When the temperature exceeded some critical value(Tc), G’ was inversely bigger than G", and its viscoelastic property is dominated by elasticity. Moreover, it was found that Tc was lowered with the dispersion concentration increasing.更多还原