Mechanical Properties and Fracture Morphology of Blends of PC with PMMA

Abstract The poly methyl methacrylate (PMMA) and polycarbonate (PC) residues were collected from waste LCD panels for use as raw materials to prepare PC/PMMA polymer blends (1/99, 3/97, 5/95, 10/90), which were extruded in a twin screw extruder. The extrudates were subsequently pelletized and then dried in an oven before injection molding into tensile bars of ASTM D638-91, type I. The tensile bars were placed in an Instron-type tensile tester and the load-elongation curves of tested 5/95 specimens demonstrated distinctively varied yielding before final brittle fracture but 10/90 showed some sign of ductile behavior, peak in the load-elongation curve attributable to formation of a neck. The tensile strength increased from 569.6 to 633.3 kgf/cm2 with PC concentration in the range of 1 to 5 wt% while it decreased at 10 wt% PC. On the contrary, transverse rupture strength increased with added amount of PC. Addition of PC could have toughened recycled PMMA matrix under impact test conditions. Finally, the fractured surfaces were examined by scanning electron microscopy and numerous fine particles dispersed in the matrix of 10/90 are regarded as PC phase, in reasonable agreement with literature results. On the other hand, fracture surface of 5/95 showed nearly homogeneous matrix phase of PC/PMMA.