REDUCTION OF RESIDUAL-STRESS IN MONTMORILLONITE EPOXY COMPOUNDS

An epoxy resin was cured while in intimate contact with small amounts of epoxyphilic montmorillonites. It was determined that cured epoxy ex ists within the montmorillonite interlayer by the observation of very high interlayer spacings, even greater than 8 nm. Generally, epoxy com pounds containing montmorillonites that had been swollen in the curing agent prior to curing exhibited larger interlayer spacings, especiall y among the non-dispersed montmorillonite layers. The maximum observed residual stress was reduced by greater than 50% in the epoxyphilic mo ntmorillonite/epoxy compounds over that of the pure epoxy. The epoxyph ilic montmorillonite/epoxy compounds generally exhibited higher values of glass transition temperature, flexural modulus, and ultimate flexu ral strength than the pure epoxy. The tyramine montmorillonite compoun ds typically had the highest values overall.