Synthesis Of Cationic Silk Fibroin Agent And Its Application In Cotton Fabric Hydrogen Peroxide Bleaching

In the hydrogen peroxide bleaching of cotton fabric the dosage of alkali is large andthe bleaching temperature is high.And therefore the problem of energy consumptionand environmental pollution is severe.In consideration of that,in this paper the wastesilk fibroin was used as raw materials. Fristly, the fibroin was dissolved, made intoprotein agent and then reacted with the self-made cross-linking cationic modifier WLSto synthesize a cationic type of biological protein additives. Then this biological proteinadditive was applied to the hydrogen peroxide bleaching of cotton fabric.The synthesisand bleaching process conditions of hydrogen peroxide bleaching using cationic silkfibroin agent were optimized by the testing of whiteness, capillary, strength and dyeingproperties.Then cation fibroin protein agent and sodium silicate was mixed.The effectof mixed agent on the bleaching of the cotton fabric was also studied. And theapplication effect of the cationic fibroin protein agent on the hydrogen perxidebleaching of cotton fabric was evaluated. The results show that the optimized processconditions of silk fibroin dissolving were sodium hydroxide25g/L, the reactiontemperature90℃, the reaction time3h and the solid-liquid ratio (volume ratio of cationfibrion agent and the solution)1:30.The optimizd synthesis conditions were the massratio of silk and WLS1:4,sodium hydroxide2g/L, the synthesis temperature90℃, thesynthesis time3h.And the optimized bleaching process conditions were H2O2(30%)20mL/L, the cationic fibroin protein agent2g/L, sodium silicate2g/L, sodiumhydroxide3g/L, temperature70℃and time50min.The results show that thewhiteness of cotton fabric bleached by the new systerm of the cationic fibroin proteinagent and hydrogen peroxide can achieve the effect of traditional high-temperatureand high-alkali bleaching cotton fabric.In addition the capillary and dyeing propertywas significantly improved.Then the cotton fabric was dyed by reactive dyes and thedyeing depth,color fastness to rubbing and washing were signifcantly improved. So thesalt-free reactive dyeing can be realized.At last the mechanism of the cationic silk fibroin agent in the hydrogen peroxidebleaching was studied.In this part, the influence of the agent on the hydrogen peroxide decomposition rate and the complexing power for metal ion,the adsorption performanceof cationic silk fibroin agent on cotton fabrics were discussed.The quasi level dynamicsmodels and quasi secondary dynamics models were used to simulate the experimentaldata and the adsorption kinetic parameters of cation protein agent on the cotton fabricswere calculated. And three theoretic adsorption models，i.e.，Langmuir，Freundlich andNernst isotherm were used to simulate the experimental data at the temperature of60℃and the thermodynamic parameters of cationic silk fibroin agent on the cotton fabricwere calculated.In this paper the adsorption dynamics performance and adsorptionthermodynamics performance of cationic silk fibroin agent on cotton fabrics werediscussed and the mechanism of the obtained cationic silk fibroin agent in the hydrogenperoxide bleaching was analyzed.The results show that the cationic fibroin proteinagent had catalytic decomposition effect on hydrogen peroxide and had complexingpower for metal ion.The calcium value was28.64mg/g, iron value was17.18mg/g andcopper value is50.8mg/g.Moreover,the adsorption capacity of the cationic fibroinprotein agent on the cotton fabric was very good.The adsorption process of the cationicsilk fibroin agent on the cotton fabric fits quasi secondary dynamics model andisotherm adsorption model fits Langmuir adsorption model.It was showed that thebleaching effect was influenced and improved by the cationic fibrion protein agent inthe hydrogen peroxide bleaching system.And the cotton fabric was cationic modified,thus the dyeing performance was improved.