No abstract

Magnetic nanoparticles were prepared from gum Arabic (GA), 2-hydroxyethylmethacrylate (HEMA) copolymer hydrogel using gamma irradiation. Factors affecting the preparation of (GA/HEMA) copolymer hydrogel and the magnetic nanocomposite of (GA/HEMA)-(Fe 3 O 4), such as irradiation dose, copolymer composition, copolymer concentration and magnetite concentration, were investigated. The swelling property of the prepared hydrogels was studied and the results showed that the swelling percent increases with increasing PH and reaches equilibrium swelling after 6 h. The obtained hydrogel and its magnetic nanocomposites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission electron microscope (TEM). The presence of Fe 3 O 4 inside the GA/HEMA-Fe 3 O 4 nanocomposites was confirmed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The magnetic properties were characterized by Vibrating sample magnetometer (VSM). Finally, the drug loading and in vitro release properties of the (GA/HEMA) copolymer hydrogel and its magnetic nanocomposites were also evaluated using endoxan as an anticancer drug model. The results showed that the optimum endoxan drug release was 97% from (GA/HEMA)-(Fe 3 O 4) nanocomposite during 210 min. It could be concluded that (GA/HEMA)-(Fe 3 O 4) nanocomposite could be used for localized drug delivery for the endoxan drug in a neutral environment of the intestine.

A novel hydrogel based on wheat flour (F) and acrylic acid (AAc) was performed by gamma irradiation. The parameters that controlled the preparation conditions were studied including irradiation dose and hydrogel composition. Characterization of the produced hydrogel (F/AAc) was done by infrared spectroscopy to confirm the structure and the change in morphology was investigated by the scanning electron microscope. The thermal stability was also investigated using thermogravimetric analysis (TGA). The swelling properties were investigated in relation to time and irradiation dose. The developed hydrogel was used for the removal of Congo Red dye (CR) from aqueous solution. Effects of different operating parameters such as effect of pH, contact time, concentration of the dye and temperature on the adsorption capacity of the dye have been studied. It was found that marvelous adsorption capacities were obtained at pH 3. The adsorption capacity at pH 3 is 19.5 mg/g for (F/AAc) hydrogel contains (15wt% AAc) at 2.5 kGy, 17.3mg/g for (F/AAc) hydrogel contains (15wt% AAc) at 20 kGy, and 13.4 mg/g for (F/AAc) hydrogel contains (20 wt% AAc) at 20 kGy. The pseudo-second-order model and the Freundlich model describe well the adsorption kinetic and isotherm, respectively.

Ethylene propylene diene terpolymer (EPDM) was blended with high-density polyethylene (HDPE) in the ratio 1 : 1. The blends obtained were vulcanized with sulfur or with peroxide vulcanizing systems. The vulcanized samples were subjected to radiation graft copolymerization with acrylonitrile (AN). The parameters affecting graft yield, such as irradiation dose, monomer concentration, and type of solvent, were investigated. It was found that sulfurvulcanized blends are less susceptible towards graft copolymerization than peroxide-vulcanized blend even after purification from residual additives. Thus, the maximum graft yield was found to achieve 5% and 45% for sulfur-and peroxide-vulcanized sam- 1Copyright 0 1997 by Marcel Dekker, Inc. Downloaded by [Queensland University of Technology] at 05