State Key Lab for Modification of Chemical Fibers and Polymer Material, College of Material Set Eng., Donghua University, Shanghai 201620, P. R China

摘要

A mode! is presented to describe the structure and formation mechanism of PAAm/clay nanocomposite gels (NC gels), by post-treating the nanocomposite gels in the presence of monomer solution. The PAAm/clay NC gels composed of a unique organic (PAAm)/inorganic (clay) network were first immersed in acrylamide aqueous solution with different concentration for certain time at room temperature. It is found that the resulting nanocomposite gels became swollen, even network collapsed in the monomer solution Then the above solutions were studied by Transmission electron microscopy (TEM), Element analyses (EA) respectively. It was elucidated that PAAm/clay nanocomposite gels are novel physical crossliking gels, the inorganic clay acts as a multifunctional physical crosslinker in place of an organic cross-linker (BIS) as used in conventional gels. With increasing the post-treatment time, PAAm chains in the PAAm/clay nanocomposite gels detached gradually from the clay surfaces in the monomer solution. TEM images further showed that the clay platelets with about 30nm in diameter and 1 nm in thickness dispersed uniformly into the solution, which are in good agreement with the literature values for hectorite platelets.