Modification of cotton fabric has been carried out through chemically induced graft copolymerization of binary mixture of acrylonitrile (AN) and 4-vinyl pyridine (4-VP) using ceric ammonium nitrate, (CAN) as initiator.

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Crosslinked copolymers of gelatin and poly(vinyl alcohol) (PVA) with excellent water absorption and water retention abilities were successfully synthesized using 60 Co c radiation. Ammonium persulfate (APS), as a water-soluble initiator and sodium bicarbonate (NaHCO 3 ) as a foaming agent were used. The best synthesis conditions were evaluated with regard to the maximum percentage of swelling as a function of the APS concentration, NaHCO 3 concentration, amount of water, and reaction time. The maximum swelling percentage (1694.59%) of the copolymer gelatin-co-PVA, was obtained at the optimum parameters [APS] 5 2.92 3 10 21 mol/L, [NaHCO 3 ] 5 7.94 3 10 22 mol/L, and 1.5 mL of water with 31.104 kGy of the c radiation dose. The copolymer was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) methods. The SEM analysis showed a highly nanoporous and cellular structure of the copolymer. The copolymer was used as a support for lipase immobilization. The optimization of the reaction conditions, including the pH and temperature for immobilization, on the basis of the hydrolysis of p-nitrophenyl palmitate, was carried out. An excellent efficiency for protein loading (70%) at pH 8.5 by the copolymer was observed. The results observed during the evaluation of the hydrolytic properties showed excellent activity of the bound lipase.The porous gelatin-co-PVA bound lipase was found to be stable at 75 C and pH 8.5; it displayed 2.326 6 0.005 U/g of lipase activity.The stability and activity of the copolymer-bound lipase were also studied as a function of the time at 75 C, and the biocatalyst was found to be stable and active up to 1 h, beyond which the activity decreased.