Study On The Modification Of Agar Fiber And Its Post-treatment

Agar is a natural marine polysaccharide extracted from red algae,is widely used in many areas,such as food,biology,chemical engineering,medicine,and other fields,due to its emulsification,thickening,non-toxicity,and stability.Agar is ideal materials for applicating in the medical field because of its good organism compatibility,excellent moisture retention and biodegradability.This paper explored the best conditions for the preparation of agar fibers via wet spinning technology,and prepared agar fibers.Agar fibers were processed by physical modification and chemical modification and agar fibers with different post-processing methods were analyzed.1.Excellent agar fibers were prepared by wet spinning technology at 20 ±2 ?,using DMSO as solvent,spinning solution concentration 12%,7% barium chloride solution as coagulation bath,3% barium chloride solution as stretching bath and at a draw rate of ¹.2.The breaking strength of fibers was 0.69 ± 0.05 c N/dtex,and the elongation at break was 104.88 ± 24.31%.The results of EDS confirmed that a small amount of Ba²⁺ existed on the surface and inside of the fiber.And barium chloride aqueous solution was a good coagulation bath for agar's wet-spinning.2.The agar fibers,prepared by using barium chloride aqueous solution as coagulation bath,were dehydrated with ethanol and then immersed in amino silicone.Amino silicone was absorbed in the surface of the fibers and formed into films on the surface of the fibers owing to the interaction between amino silicone and the hydroxyl groups on the surface of fibers.The fibers immersed in amino silicone were glossy,smooth and soft and the phenomenon of adhesive was disappeared,and the tensile strength increased from 0.62±0.09 c N/dtex to 0.68±0.11 c N/dtex,and the elongation at break increased from 69.15±15.77% to 104.88±21.40%.The water contact angle of the fiber increased from 82.6° to 106.4°,and the hydrophobic capacity of the fiber increased.The amino silicone film on the fiber surface can block the air during buring,making the limiting oxygen of the fiber increased to 20%.3.The dehydrated agar fibers are post-treated with sodium tetraborate.The sodium tetraborate can conduct crosslinking reaction with hydrogen bonding on the surface of agar fibers,and the phenomenon of adhesive was solved.However,the fibers become hard and brittle,with the tensile strength decreased from 0.62 c N/dtex to 0.53 c N/dtex and the elongation at break decreased from 69.15% to 59.56%.The morphology characterization can be seen that the fibers surface was gully,which makes water contact angle change to small,but the flammability of the fiber is improved and it changes from flammable fiber to combustible fiber.4.The agar fibers prepared by wet spinning were treated with epichlorohydrin for cross-linking treatment.The optimum condition of epichlorohydrin cross-linked agar fibers was determined by exploring the concentration of cross-linking agent,reaction temperature,and reaction p H.The degree of cross-linking can be inferred by the change in the morphology of the fibers,the mechanical properties of the fibers after cross-linking are reduced,and the alkaline environment in the cross-linking process can also reduce the mechanical properties of the fibers.The FTIR results indicated that the cross-linking reaction between agar and epichlorohydrin has occurred,and the crosslinking agar fibers have reduced the ability of water absorption.