Study On Grafting Of Silk With Hydroxyl Containing Acrylate Monomer Catalyzed By HRP

In this work,horseradish peroxidase?HRP?was applied to catalyze the grafting modification of silk fabric to improve the crease resisitance property of the silk fabrics.Firstly,the influence of different conditions on the activity and stability of HRP were discussed.And then the hydroxyl containing acrylate monnmer were grafted onto silk fabric via HRP-catalyzed ATRP method and HRP/H₂O₂/ACAC system,respectively.The optimal reaction conditions of grafting were investigated.The structure and properties of grafted silk fabric were characterized.The results showed that the activity and stability of HRP had a significant difference under variable conditions.HRP activity decreased with the temperature increasing.When pH value was in netural or weak alkaline condition?7-9?,HRP activity kept at a higher level.With the increase of the dosage of H₂O₂ and ACAC,HRP activity reduced gradually.High concentration HRP is profitable to maintain its stability under a weak alkaline and low temperature condition.HRP was used as catalyst of ATRP to take the place of transition metal,which accorded with the environmentlly friendly idea.HEMA,HPMA and HPA were successfully grafted onto the surface of silk fabric by HRP-catalyzed ATRP.The optimum reaction conditions were obtained as follows:monomer concentration 120²10%?o.w.f?,HRP concentration360⁴80U/mL,the molar ratio of HRP to NaAsc 1:150,reaction at 50⁶0?,reaction time for 24h.Based on HRP/H₂O₂/ACAC system,the optimum reaction conditions of grafting with HEMA,HPMA on silk fabric were as follows:monomer concentration 120%?o.w.f?,HRP concentration 240U/m L,the concentration of H₂O₂ 3.4×10^-7mol/mL,the concentration of ACAC 2.0⁴.0×10^-4mol/mL,reaction at 50?for 12h.The structure and properties of grafted silk fabric based on two systems were characterized,respectively.Raman and infrared spectrum showed that the monomers were successfully grafted onto the surface of silk fabric.XPS and thermal analysis further illustrated that the monomers were successfully grafted on the surface of silk fabric.XRDanalysis indicated the grafting reaction mainly occurred in amorphous region of silk.Amino acid analysis of grafted silk by HRP/H₂O₂/ACAC system showed that the grafting reaction mainly occurred in amorphous region of silk,and hydroxyl from tyrosine is an important reactive site.SEM photos showed that the surface of grafted silk became rougher with the increase of grafting yield,and the polymer obtained by ATRP was much well-distributed.The crease-resistant recovery property of grafted silk fabrics was greatly improved.Especially,the grafting by ATRP method was more effective in improving wet crease recovery angle?WCRA?.The breaking strength in warp and weft of grafted silk fabrics both decreased and the moisture regain descended slightly.