Rubber-toughening of polycarbonate-nylon blends

Abstract

Incompatible and brittle polymer blends of polycarbonate (PC) and nylon-6 [polyamide (PA)] have been compatibilized with high-molecular-weight bisphenol A epoxy resin and toughened by reactive and unreactive core-shell rubbers. The epoxy resin has proved to be an effective, reactive, in situ compatibilizer for the incompatible PC-PA blends. Rubber particles in the PC-PA blends can be controlled so as to be distributed in either PC, PA, or both phases. Unreactive methyl methacrylate-butadiene-styrene (MBS) rubber is more compatible with PC than with PA and tends to reside in the PC phase and near the PC-PA interface. Reactive MBS rubber containing maleic anhydride and methacrylic acid (MBS-MA) can react with nylon end groups, and the resulting nylon-linked rubber particles are retained within the nylon phase. Rubber distributed in the PC phase is more effective in toughening the PC-PA blends than that distributed in the nylon phase. Rubber-toughening of blends with PC as a matrix is more efficient than in blends with nylon as a matrix.