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Effect of mixed solvent consisting of water and organic solvent on photografting of glycidyl methacrylate on polyethylene film



The effect of a mixed solvent consisting of water and organic solvents such as acetone and methanol on the photografting (λ > 300 nm) of glycidyl methacrylate (GMA) on linear low-density polyethylene film (thickness = 30 μm) was investigated at 60°C. Xanthone was used as a photoinitiator by coating the film surfaces with it. The maximum percentage of grafting was observed at a certain concentration of organic solvent in the mixed solvent, which depends on the nature of organic solvents such as methanol (ca. 5 vol %) and acetone (ca. 15 vol %). On the basis of attenuated total reflection infrared spectroscopy of the grafted film, the absorbance ratio of the carbonyl peak of grafted poly(GMA) chains at 1728 cm−1 to the methylene peak of polyethylene substrate at 1460 cm−1 increased with increasing the concentration (0–15 vol %) of organic solvent, which was commonly observed for methanol and acetone. Distribution of grafted poly(GMA) chains in the cross section of the grafted film was examined using a scanning electron microscope. The results showed that the grafted chains of the GMA-grafted samples prepared in water solvent tended to penetrate into the inside of the film compared to those of the grafted samples prepared in the mixed solvent due to higher affinity of the GMA monomer to the polyethylene substrate compared to the organic solvents used. Grafted poly(GMA) chains were aminated with ethylenediamine (En) in N,N′-dimethylformamide at 70°C for 3 h. It was found that the reactivity toward En was higher for the sample prepared in mixed solvent than for the sample prepared in water solvent. The aminated GMA-grafted sample had the ability to adsorb cupric ions, showing that a higher amount of adsorbed cupric ion is recorded for the sample prepared in mixed solvent than for the sample prepared in water solvent. Complexes of aminated GMA-grafted chains with cupric ion exhibited the catalytic activity of decomposition of hydrogen peroxide at 50°C, and its ability depended on the location of the grafted chains in the film substrate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 994–1000, 2004