Effects of graft modification on the properties of chitosan for warp sizing

Abstract

Unmodified chitosans exhibit poor water-solubility, are unable to meet the water-based sizing requirement satisfactorily, and have limited industrial application as warp sizes. In order to impart good water-solubility to chitosans and extend their practical utilization in textile field, various amounts of hydrophilic vinyl monomers-acrylamides (AM) were grafted onto the molecular chain of chitosan. A series of chitosan-g-PAM with different grafting percentages were prepared and the composition of the graft copolymer was characterized by FTIR. Then effects of the graft modification on main sizing properties of chitosan were surveyed in terms of water-solubility, apparent viscosity, mechanical properties of sizing film, and adhesion to fibers. It was found that, by grafting appropriate amounts of AM onto the molecular chain of chitosan, the watersolubility, viscosity stability, mechanical properties of sizing film, and adhesion to fibers were improved markedly. In view of overall performance of the grafted chitosan sizes, the optimum value should be 11.90 % when the grafting percentage was in range of 0-26.89 %.