Synthesis and Grafting Efficiency of Poly(vinyl alcohol)-graft-Fibroin Peptides.

A new product of poly(vinyl alcohol)-g-fibroin peptides (PVA-g-FP) is produced by graft-copolymerization of PVA with allyl fibroin peptides (AFP). The AFP was obtained from a nucleophilic substitution reaction of fibroin peptides (FP) with allyl chloride. The optimal parameters of preparing the PVA-g-FP, corresponding to the acquired grafting efficiency, 10.1 wt%, were selected on the basis of the orthogonal experiments design of L16 4^5, and the influence of reaction conditions on the grafting efficiency are discussed in detail, according to the data obtained from the orthogonal experiments. The FP was successfully modified and grafted onto the PVA macromolecules, which was confirmed by the analyses of the FTIR spectra of AFP and PVA-g-FP, and the reaction mechanisms for the formation of AFP and PVA-g-FP are proposed. The results of the orthogonal experiments have indicated that, relative to other parameters, the reaction temperature and the molar ratio of potassium peroxide sulphate (KPS) to AFP seemed to be more effective on the grafting efficiency. The highest grafting efficiency of FP was obtained under the reaction temperature of 60°C for 3 h reaction time, with AFP/PVA weight ratio of 3/7, and molar ratio of KPS/AFP of 1/20, having a solution concentration of 10 wt%. The product may be potentially useful in the fields of biomaterials, textile industry, and chemical engineering.