Study On Hydrophilic Modification Of Vinyl Monomer Grafted Onto Jute Fabric Catalyzed By Laccase

Jute fibers are rich in lignin (13.6%-20.4%), but the phenolic oxygen free radicalsproduced by laccase catalysis of the jute fibers can not initiate vinyl monomer free-radicalchain reaction, and only in the presence of organic mediators such as tertiary butyl hydrogenperoxide(t-BHP), graft polymerization between lignin and the vinyl monomer could occur.The previous study indicated that, in the presence of the mediator the grafting rate ofacrylamide to lignin on the jute fabric catalyzed by laccase is relatively low in theheterogeneous reaction. This paper presents a novel grafting method of the jute fabric toovercome this shortcoming. First, eugenol, which contains both phenolic hydroxyl monomerand vinyl C=C as an intermediate monomer, was grafted to the lignin-rich jute fabriccatalyzed by laccase. Then, further grafting polymerization of eugenol monomer to theEugenol-bridged jute mediated by laccase/t-BHP was investigated in this study.In this paper, the surface of the bridging-grafted eugenol to jute fabric (jutefabric-g-eugenol) were characterized by XPS. The bromine determination was used tomeasure the content of the C=C in jute fabric-g-eugenol.In this way, the grafting rate ofeugenol was calculated and the optimal reaction conditions for grafting eugenol to the jutefabric were optimized. The results showed that: laccase can indeed catalyze grafting eugenolto jute fabric and the C=C of eugenol has not been destroyed. The optimum reactionconditions were50℃, pH4,4h, eugenol concentration of5mmol/L, and laccase1.68U/mL.The hydrophilic acrylamide and acrylic as grafting monomers, were grafted to the jutefabric-g-eugenol by laccase.The grafted acrylamides to jute fabric-g-eugenol werecharacterized by FT-IR and elemental analysis. The Kjeldahl nitrogen determination methodwas used to measure nitrogen content of jute graft-copolymer, and the graft rate and graftefficiency were calculated; and elemental analysis was used for characterization of graftedacrylic in jute fabric-g-eugenol. The results showed that acrylamide was indeed grafted ontothe C=C of the jute fabric-g-eugenol in the laccase/t-BHP system,. The optimum conditionsfor jute fabric-g-eugenol grafted acrylamide were as follows: temperature50℃, pH5,acrylamide/jute fabric-g-eugenol mass ratio4/1, laccase concentration2.4U/mL, reactiontime12h, t-BHP concentration2.4mL/L. In laccase/t-BHP system, jute fabric-g-eugenol canbe grafted with acrylic acid too.Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) werecarried out to study the thermal properties of jute fabric-g-eugenol before and aftermodification. The wetting time, equilibrium moisture regain and static contact angle weretested to analyse the wettability of jute fabric-g-eugenol before and after modification. Theresults showed that the thermal stability and the wettability of jute fabric-g-eugenol graftedwith acrylamide or acrylic acid incresed.