Polycarbonates find applications in food industries due to their clarity and ductility. Sometimes failure of a polycarbonate part occurs. In food blender jars molded from polycarbonate, cracks were observed in the sealed joint only a few days after assembly. The root cause was investigated via microscopy, FTIR and GC-MS analyses. It was determined the cracks initiated and radially propagated from the bottom raised lip of the part. The root cause was a combination of a high stress in the lip region due to molding and design, and environmental chemical compounds, i.e., esters from a melt nut used in the assembly. The failure was typical environmental stress cracking (ESC) problem.
展开▼
