Abstract: For study the relation between grafted starch physicochemical properties and its sizing performance, grafted cationic starch (GCS) with different graft ratios (GR) were prepared by grafting cationic starch with acrylamide, β-hydroxyethyl methacrylate and n-butyl acrylate using microwave-assisted method, the grafted copolymer was characterized by FT-IR and XRD. The physicochemical characteristics of GCS were studied, as well as its sizing performances. Results showed that, within a certain range of GR, the physicochemical properties of GCS improved, including enhanced hydration capacity and rheological propertiy, improved anti-retrogradation and paste clarity, but an excessive high graft level could deteriorate the physicochemical properties of starch. Sizing performance of GCS increased with the increase of GR, the tensile strength, elongation at break and abrasion resistance reached an optimum value when GR was 13.58%, and then decreased with further growth of graft level. The research results also indicated that the improved physicochemical properties of grafted starch were closely related to its sizing performance improvements.

Key words: grafted starch, graft ratio, microwave, physicochemical characteristic, sizing