NOTCHED IMPACT STRENGTHS OF COMPACT AND MICROCELLULAR POLYCARBONATE

摘要

The notched impact strength of compact polycarbonate depends on the temperature, thickness (with a tough brittle transition at thickness increases), contribution of sharp notches (transition of the flat tension to the flat stretching condition) and processing parameters. Microcellular polycarbonate foams produced by injection molding process using physical blowing agent (MuCell) with or without gas counterpressure process, shows significantly higher notched impact strength then compact polycarbonate, if the compact polycarbonate is brittle under the same test parameters. When the compact polycarbonate breaks toughly, the notched impact strength of microcellular foams is always significantly lower. Therefore it is very important to pay attention to the test parameters by comparing the notched impact strength between compact and microcellular polycarbonate.