Study On Salt-resistant Modification And Properties Of Calcium Alginate Fibers

With the rapid development of society,humans have developed and utilized earth resources,resulting in greenhouse effect and environmental pollution,which have made people’s lives potentially threatened.The development of new environmentally friendly new materials to meet human demand for fiber products has become urgently Task.Alginate extracted from algae in the sea is a natural macromolecule raw material that can be degraded by microorganisms and does not put pressure on the environment.It can be used to adsorb heavy metals in wastewater,printing,and thickening in dyeing.Additives and other aspects of food additives.The calcium alginate fiber prepared from alginate will displace Ca²⁺in the chelate structure in the presence of a salt solution,causing some changes in its properties,resulting in poor performance.In this dissertation,citric acid and glyoxal were used as modifiers to modify calcium alginate fibers.The optimal method for the salt-tolerant modification of citric acid and glyoxal was studied.The mechanical properties of the fibers before and after modification were studied.Stability and liquid-absorbing and liquid-holding properties are expected to expand the application of seaweed fibers.The research content mainly includes the following parts:l.The calcium alginate fiber raw materials used in this paper were prepared by the laboratory’s own wet spinning,and modified calcium alginate fibers were prepared using citric acid as a modifier.The effects of the concentration of modifier citric acid,the concentration of sodium hypophosphite catalyst,cross-linking time and cross-linking temperature on the degree of fiber swelling were explored through single-factor experiments and orthogonal tests to determine the optimal modification process.Conditions:citric acid concentration 7%,sodium hypophosphite concentration 5%,cross-linking time 120 s,cross-linking temperature 160°C.Infrared spectroscopy,thermogravimetry,and scanning electron microscopy analysis demonstrated that the citric acid interacted with calcium alginate fiber macromolecules to form ester bonds;the salt tolerance,mechanical properties,and aspiration of the calcium alginate fibers before and after modification were compared.With respect to the liquid retention properties,it was found that the salt tolerance of calcium citrate modified calcium alginate fibers was improved compared to that of unmodified calcium alginate fibers,and the breaking strength was improved,but the elongation at break was improved.The rate dropped,the liquid absorption performance and the liquid retention performance decreased.2.The calcium alginate fiber raw material used in this paper was prepared by the laboratory’s own wet spinning,and the modified calcium alginate fiber was prepared with glyoxal as the modifier agent.The effects of the modifier glyoxal concentration,the concentration of catalyst magnesium chloride,the crosslinking time and crosslinking temperature on the degree of fiber swelling were investigated by single-factor experiments and orthogonal tests,and the optimum modification process conditions were determined:The concentration of glyoxal was 10%,the concentration of magnesium chloride was 3%,the crosslinking time was 120 seconds,and the crosslinking temperature was 150°C.Infrared spectroscopy,thermogravimetry,and scanning electron microscopy analysis demonstrated the aldol condensation reaction of aldehyde groups on glyoxal with calcium alginate fiber macromolecules;the salt tolerance,mechanical properties,and absorption of calcium alginate fibers before and after modification were compared.Liquid and liquid retention performances showed that the salt resistance of glyoxal-modified calcium alginate fibers was improved compared to that of unmodified calcium alginate fibers,and the breaking strength was improved,but the elongation at break decreased.Absorption performance and liquid retention performance decreased.