锂皂石复合聚合物纳米凝胶的研究

Research on hectorite-composite polymeric nanogels

采用反相微乳液聚合合成了具有化学和物理双网络结构的锂皂石复合聚合物纳米凝胶（HCPN）,重点探讨了锂皂石用量对HCPN吸水速率、吸盐水率、凝胶强度、抗剪切性能、pH响应性和膨胀性的影响,并通过透射电镜（TEM）、XRD衍射对HCPN的形貌和结构进行表征。结果表明HCPN吸水360min左右基本达到平衡,平衡吸水率为67-103g/g。锂皂石的加入可以提高HCPN的凝胶强度和抗剪切性,当锂皂石用量为1.0%,HCPN吸水凝胶体的凝胶强度高达9.1Pa.s。XRD证实锂皂石的结晶结构转变为无定型结构,以纳米片层结构无规分布于聚合物凝胶基体中。TEM表明HCPN基本为球形,形状比较规整,粒径为30-65nm,平均粒径为43nm,HCPN的溶胀具有明显的pH响应性,吸水溶胀300min后粒径可增加到3~4μm。

Hectorite-composite polymeric nanogels（HCPN）were synthesized by inverse microemulsion polymerization.Factors influencing the water absorbency,salt absorbency,gel strength,shear-resistance,pH-sensitivity and expansibility of HCPN,such as hectorite amount were investigated.Morphology and structure of HCPN were characterized by TEM and X-ray diffraction.It was found that HCPN approached water absorbency equilibrium around 360min and had equilibrium water absorbency of 67~103g/g.Gel strength,shear-resistance of HCPN were enhanced by addition of hectorite.Gel strength of HCPN reached as high as 9.1Pa.s when the amount of hectorite was 1.0%.X-ray diffraction results indicated that the crystal structure of hectorite was transformed into an amorphous structure,with its nanosized sheets randomly distributed in the polymer gel matrix.TEM data showed that HCPN had spherical-like and regular shape,with particle size range of 30-65nm and the average particle size of 43nm.HCPN showed obvious pH-responsive swelling behavior.After swelling for 300min,particle size of HCPN increased to 3-4μm.