AbstractBinary blends of poly(vinyl chloride) (PVC) and chitin‐graft‐poly(2‐methyl‐2‐oxazoline) showed miscibility in the blend fraction range of the latter lower than ca. 10 wt.‐%. The glass transition temperature of PVC, which was determined by differential scanning calorimetry, changed to lower temperatures with increasing modified chitin contents up to 10 wt.‐%. Segmental interaction between PVC and the graft copolymer was confirmed by the carbonyl stretching band shift in the F