A Study on the Anionic Graft Polymerization of Acrylamide onto Silk Fibroin

견피브로인의 아크릴아미드에 의한 음이온 그라프트 중합에 관한 연구

Sodium metalated silk fabric was prepared by means of an ion exchange reaction between the preswollen substrate and methanolic sodium methoxide solution. The metalation percent increased with the increase of reaction temperature and time and the concentration of sodium methoxide in methanol. The metalation reaction was enhanced by the addition of dimethyl sulfoxide, pyridine, and dimethyl formamide to the system as a cosolvent. The swelling effect of solvents on the metalation percent was also examined and the effect was sucessfully explained in terms of solubility parameter concept. In order to find the site of metalation, the hydroxyl and amino groups of amino acid residue of silk fibroin were blocked by acetylation with acetic anhydride. The metalation percent decreased in a linear relation with the increase of acetyl value. From the result, it was suggested that the hydroxyl group in silk fibroin is to be a site of metalation reaction. The kinetics was introduced in metalation reaction, assuming that all the hydroxyl groups of amino acid residues in silk fibroin have the same metalation function. The apparent activation energy of sodium metalation was about 6.8 Kcal/mole. Acryl amide was anionic graft polymerized onto sodium metalated silk fabric under various reaction conditions including the variations of acryl amide concentration. metalation percent, reaction temperature, reaction time, and solvents. The graft yield increased with the increase of monomer concentration, metalation percent, reaction temperature, and reaction time, whereas with the increase of the dielectric constant of solvent, the reduced yield was obtained. Poly(ß-alanine) in the grafted silk was quantified by means of amino acid analysis and the transition ratio(t-ratio) of poly(acrylamide) to poly(ß-alanine) was calculated. T-ratio increased with the increase of graft yield. The dyeability and crease-recovery of the grafted silk fabric were improved by increasing the graft yield, but the handle and drape were impaired in comparison with the untreated silk fabric.