The effects of reactive compatibilizer and processing temperature on the morphology and the mechanical properties at the weld line of 60/40 (wt/wt) polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) copolymer blends were investigated. Amine functionalized styrene/n-phenyl maleimide/maleic anhydride terpolymer (amine-SPMIMA) was used as the in-situ reactive compatibilizer for PC/ABS blend. Weld tensile strength increased as the content of amine-SPMIMA was increased. Weld impact strength showed maximum value for the blend containing about 3% amine-SPMIMA. The variation in the mechanical property at the weld line was correlated with the change in the morphology of the blend. (C) 2008 Wiley Periodicals, Inc.