Abstract: In order to investigate the effect of amylose content on the properties of grafted starch size, branched chain starch and amylose were used as raw material, and mixed branched amylose which proportion of branched chain starch and amylose were at 10:0, 7:3, 5:5, 3:7 and 0:10, respectively, was graft copolymerized by methacrylic acid, and acetic acid vinyl ester, which proportion was 1:1, and equal to 40% of starch content. Butyric acid two methyl ester and ammonium cerium nitrate were used as initiator to obtain grafted starch size. The adhesive force of grafted starch size to pure cotton (40S), polyester/cotton(45S) and the mechanical properties of starch film were tested. Results indicated that when the content of the branched chain was less than 70%, the adhesion of the grafted starch sizing agent to the cotton and polyester/cotton roving increased with the decrease of the content of the straight chain; When the content of the branched chain exceeded 70%, the adhesion of the grafted starch sizing agent declined. And the change of the ratio of the amylopectin had a larger impact on polyester/cotton roving than that of the cotton roving. With the increase of the straight chain content, the mechanical properties of the graft starch film are increased.

Key words: grafted starch size; branched and straight chain; adhesion; film; breaking strength