Preparation Of Crosslinked Carrageenan Fibers

Carrageenan is a natural polysaccharide extracted from red algae. It is water-soluble and has a gel characteristic. Carrageenan fibers have been successfully prepared in our research team. In order to increase the mechanical strength of carrageenan fibers, cross-linking carrageenan fibers were studied with the reaction between carrageenan macromolecule and cross-linking agents.First of all, the cross-linked structure was formed between carrageenan macromolecules and metal ions as metal ions can form complexes with carrageenan. Carrageenan fibers were made with different types of carrageenan and different kinds of metal salt solution, the most appropriate type of carrageenan is iota-carrageenan and the most appropriate type of metal salt solution is BaCl2 solution.Secondly, the hydroxyl groups in the carrageenan macromolecules can react with cross-linking agents such as epichlorohydrin, succinic anhydride, maleic anhydride, PMDA to form ether bond or ester bond. The result shows that the best cross-linking agent is epichlorohydrin. In order to obtain high quality crosslink ing carrageenan fiber, the optimal reaction condition is as follows:the epichlorohydrin added with the concentration of 6.25%, the reaction temperature is 90℃, the reaction time is 2.Oh, and the pH value is 10.0. In the water reaction system, the succinic anhydride or maleic anhydride can not reacted with carrageenan because of the hydrolysis of the anhydride and has no desired product. And so does PMDA. In the oil reaction system, the succinic anhydride or maleic anhydride can react with carrageenan to obtain cross-linked product.Finally, the epichlorohydrin cross-linked carrageenan fiber was prepared via wet-spinning technology. The fiber strength is 12.3cN/tex which is 2.3 times of carrageenan fibers and the elongation is 13.46% which is 1.25 times of carrageenan fibers. The mechanical strength of cross-linked carrageenan fibers is significantly improved.