MECHANICAL PERFORMANCE OF BLENDS OF POLY(METHYLMETHACRYLATE) AND BISPHENOL-A POLYCARBONATE WITH AND WITHOUT WELD LINES

The mechanical performance of blends of polymethylmethacrylate (PMMA) and bisphenol-A polycarbonate (PC), prepared by extrusion and subseque nt injection moulding, was analyzed in tensile and impact tests. Test bars without and with a weld line (in the center) were used. The tough ness of the blends was correlated with their phase morphology, which w as characterized by transmission electron microscopy. The properties o f the blends turned out to depend predominantly on the polymer forming the matrix. A PC matrix made the blends ductile and a PMMA matrix bri ttle or semiductile. Blends with a PC matrix exhibited ductile shear y ielding and neck formation even in the presence of a weld line, while blends with a PMMA matrix broke directly in the weld line. Most intere sting is that, in blends with a PMMA matrix and PC domains, the PC act s as an impact modifier making the ('semiductile') blends much tougher than pure PMMA.