Preparation and properties of hybrids of organo-soluble polyimide and montmorillonite with various chemical surface modification methods

Montmorillonite (MMT)/Organo-soluble polyimide (PI) hybrids were prepared using a monomer solution intercalation polymerization method. The organo-soluble polyimide was based on pyromellitic dianhydride and 4,4'-diamino-3,3'-dimethyldiphenylmethane. The MMT was ogano-modified with three types of intercalation agents: amino acids, primary aliphatic amines and quaternary ammonium salt. The dispersion behavior of MMT in organic solvents and polyimide depends on the type of the functional group and the bulky group of the intercalation agent. The MMT modified with 1-hexadecylamine is observed to possess the best dispersion behavior. The properties of a MMT/PI hybrid are also greatly dependent upon the dispersion behavior of MMT particles. When the MMT is well dispersed, a MMT/PI hybrid would possess desired properties such as strengthening and toughening at the same time, improved thermal stability, decreased thermal expansion coefficient, retaining of the solubility of the polyimide matrix and high optical transparency. (C) 1999 Elsevier Science Ltd. All rights reserved.