Abstract:

In order to solve the swelling problem of sodium alginate / krill protein(SA /AKP) composite fiber in salt solution, salt resistant SA/AKP composite fiber was prepared by cross-linking reaction of boric acid with composite fiber. Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimeter and X-ray diffraction were used to study the chemical structure, thermal properties and crystallinity of composite fiber. The relationship between cross-linking degree and fiber morphology was investigated, and the correlation between fiber mechanical properties and cross-linking temperature was evaluated. The results show that the B—O bond is formed by the reaction between boric acid and sodium alginate. The swelling degree of the SA/AKP composite fiber decreases and the equilibrium of the fiber is balanced at 30 min and 80 ℃ after the cross-linking time is prolonged and the cross-linking temperature increases. The swelling degree of the cross-linking fiber can be reduced to 82.30% by 136.99%, and the salt resistance of the fiber is improved obviously. At the point, the breaking strength of the fiber is 2.18 cN/dtex. The breaking strength of the cross-linking fibers with the cross-linking temperature firstly increased and then decreases, and a longitudinal groove structure exists on the surface of the cross-linking fiber and the non-cross-linking fiber. After the cross-linking, the fiber was treated with salt solution, the surface still has the groove structure.

Key words: sodium alginate, krill protein, composite fiber, boric acid, salt otlerance, cross-linking reaction