Cross-linking Preparation And Properties Of Calcium Alginate Fibers Research

Alginates are natural polysaccharide extracted from various species of brown algae. Alginate gelation takes place when divalent cations interact ionically with blocks of guluronic acid residues, as usually called "egg-box". So alginates are usually used in textile industry, printing and dyeing and absorbing cation of heavy metal and transition metal. But the structure of "egg-box" is destroyed in the Na+aqueous solution, because of ion-exchange process. The Ca2+ions present in polymannuronate units are exchanged with Na+ions. Thus the fiber dissolved and had great impact on its strength. In order to improve the salt and alkaline resistance of the alginate fiber, cross-linking alginate fibers were studied with the reaction between alginate macromolecule and cross-linking agents. The sphere of application of calcium alginate fiber was expanded continuously.The main achievements on this research has been carried out in three fields.1、Alginate was extruded into coagulation bath to form continuous calcium alginate fiber. Alginate fiber was crosslinked by glutaraldehyde. Effects of technological conditions such as crosslinker concentration, crosslinking treatment time, temperature on properties of crosslinked fiber are researched. The optimal crosslink reaction condition is:the temperature is30℃,the concentration of glutaraldehyde is8%, the reaction time is3.0h. The crosslink reaction was proved by FTIR Analysis. By using SEM, TG test, swelling behavior test and tensile property test, the Salt-tolerance of crosslinked fiber is higher than that of uncrosslinked fiber. Swelling capacity of modificated calcium alginate fibre in salt water was98%,27%of unmodified fiber. The breaking strength of the crosslinked fiber is2.23cN/dtex. Fiber treated by salted water keeps a good morphology. Guaranteed the happen of the aldol reaction.2、The hydroxyl groups in the calcium alginate macromolecules can react with epichlorohydrin, which lead to the formation of either link. The epichlorohydrin content is0.5*10-2mol/l, the reaction temperature is45℃,the reaction time is3.0h, and the pH value is10.0. As result, the strength and the kaline resistance properties were increased, the reaction obtained heterogeneous cross-linked structure. The strength improved6.1%, The breaking strength of the crosslinked fiber is2.83cN/dtex, which is analogous to cotton fibers, and much higher than wool fibers. The experimental results indicate that the weight-loss ratio of crosslinked fiber is4.51%after laundered three-quarters of an hour by detergent which is3%concentration. The epichlorohydrin crosslinked alginate fiber has the high adsorption quality and high salt resistance...