Preparation and properties of montmorillonite/organo-soluble polyimide hybrid materials prepared by a one-step approach

Montmorillonite (MMT)/organo-soluble polyimide (PI) hybrids were prepared using a one-step approach. The organo-modified MMT was dispersed in a solution of diphenylether-3, 3′4,4′-tetracarboxylic dianhydride and 4,4′-diamino-3,3′-dimethyldiphenylmethane. The solution polycondensation followed by a direct solution imidization at 180 °C resulted in MMT/PI hybrid solutions. From wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) results, the MMT is basically exfoliated in the hybrid films cast from the solutions when the MMT content is below 5 wt%. Further increase in the MMT content leads to severe aggregation. The properties of a MMT/PI hybrid are significantly dependent upon the MMT content. When the MMT content is below 6 wt%, the introduction of the MMT leads to strengthening and toughening to the PI matrix at the same time. The introduction of the MMT also results in improved thermal stability, marked decrease in coefficient of thermal expansion, slight increase in glass transition temperature and increase in modulus.