原子力显微镜对聚合物絮凝体微观结构的研究

AFM Study of Microstructure of Polymer-clay Floccule

由粘土与部分水解聚丙烯酰胺(HPAM)产生的絮凝体是一类非常重要的堵水剂。用原子力显微镜研究了粘土、HPAM以及不同配方的粘土与HPAM形成的絮凝体的微观结构。实验结果证实了絮凝体存在由聚合物桥接吸附在粘土表面上所形成的网状结构;通过理论计算说明,1个聚合物分子可以吸附在2个粘土片上,而1个粘土片或粘土片聚集体可以吸附多个聚合物分子,吸附个数与聚合物在粘土表面上的饱和吸附量以及聚合物的相对分子质量有关;絮凝体中粘土的含量越高且表面为HPAM覆盖分数接近0.5时,絮凝体的等效半径越大,封堵效果越明显。

Floccule formed by mixing clay with partially hydrolyzed polyacrylamide (HPAM) was a kind of plugging agent used to block the high-capacity channel of strata. Atomic Force Microscopy (AFM) has been performed to measure the microstructure of the clay, HPAM and floccule that formed by different magnitude of clay and HPAM. It has been confirmed that net structure originated from polymer bridging adsorption existed in AFM picture of floccule. Theoretical computation has shown that one polymer molecule could adsorb between two clay particles and one clay particle could adsorb several polymer molecules which were related to saturated adsorption of polymer in particle surface and polymer molecular weight. The equivalent radius of floccule grew with increasing clay content and surface coverage fraction by polymer molecules closing to 0.5.