Gel permeation chromatography (GPC) and solid-state C-13-NMR techniques were used to analyze the structural changes of poly(vinyl chloride) (PVC) in blends of a low-density polyethylene (LDPE) and PVC during melt blending. The GPC results showed that the weight-average molecular weight (M-w) of PVC increased with LDPE content up to 13.0 wt % and then decreased at a LDPE content of 16.7 wt %, whereas the number-average molecular weight remained unchanged for all of LDPE contents used. The C-13-NMR results suggest that the increase in M, was associated with the formation of a LDPE-g-PVC structure, resulting from a PVC and LDPE macroradical cross-recombination reaction during melt blending. (C) 2004 Wiley Periodicals, Inc.