Preparation And Properties Of Chitosan Modified Polysaccharide Fibers

Chitosan, as a natural polysaccharide, has many excellent natural properties. While the high price of chitosan fiber has limited its application. Polysaccharide fiber is one kind of natural fibers, with lower price for raw materials widely found in nature, but also has its own disadvantages. Two kinds of polysaccharide fibers, viscose fibers and alginate fibers, were chosen as the research objects. The fiber surface is coated with chitosan in chemical modification methods, aiming at giving polysaccharide fibers excellent performance of chitosan.Firstly, selective oxidization of polysaccharide fibers with sodium periodate is carried out. The influences of sodium periodate concentration, oxidizing temperature and time on strength, mass loss and fiber aldehyde groups content are studied. And the optimum process conditions are obtained, in which way fibers feature more aldehyde groups, lower strength loss and mass loss.Afterwards, oxidized polysaccharide fibers are grafted with chitosan. The reactive amino groups on the chitosan form a combination of Schiff base with aldehyde groups in oxidized fibers, forming a covalent bond in the fiber surface. The influences of process conditions such as chitosan concentration, grafting temperature, grafting time and pH value on mass gain of fibers before and after modification are studied. Also, the changes of strength and absorbency of fibers before and after modification are explored.Lately, the original and modified fibers are dyed with direct dyes. The influences of chitosan concentration, grafting temperature, grafting time and pH value on fiber dyeing properties are studied. The results show that the polysaccharide fiber grafted with chitosan has no significant change of strength, but more mass and dye uptake. In the same time, better wash durability is gained.