TOUGHENING POLYCARBONATE WITH CORE-SHELL STRUCTURED LATEX-PARTICLES

The toughness as a function of temperature of polycarbonate modified b y blending with core-shell structured latex particles was evaluated. C omparisons were made among a commercial core-shell latex (MBS), other core-shell (CS) latexes that incorporated a single component rubbery c ore, and a new class of interpenetrating polymer network (IPN) core-sh ell latexes with two elastomers in the core. Notched tensile tests dif ferentiated among the blends in terms of their toughness. The most eff ective modifier at low temperatures was the commercial MBS latex. The CS latexes produced blends that were only slightly less tough than the MBS blends despite better dispersion of MBS and better adhesion to th e matrix. The IPN blends were the least tough at low temperatures; how ever, at 25 degrees C, a blend with IPN had the highest impact strengt h. Differences between CS and MBS blends were attributed to difference s in the percent of butadiene-containing rubber and the chemical natur e of the shell. A comparison among the CS latexes showed that increasi ng the acrylonitrile content of the shell increased the toughness, and increasing the rubber content or the gel fraction of the core increas ed the toughness. (C) 1996 John Wiley & Sons, Inc.