The effect of cold rolling on crazing of polycarbonate

This work shows the crazing behaviour of pre-oriented polycarbonate after tensile testing close to the liquefaction temperature of nitrogen (77 K). The pre-orientation achieved by cold rolling reveals the presence of crazes from 0% to 50% pre-orientation. Crazes were suppressed at 75% pre-orientation. Surface crazes were observed and, where they did occur, the form of the crazes changed as the pre-orientation increased. Increasing pre-orientation resulted in a decrease in craze density, depth and length. This reduction in craze dimension and concentration is attributed to the molecular orientation.