MEMBRANE-PROPERTIES OF POLYETHYLENE FILMS PHOTOGRAFTED WITH HYDROPHILIC MONOMERS

Hydrophilic monomers such as methacrylic acid (MAA), 2-(dimethylamino) ethyl methacrylate (DMA) and N-isopropylacrylamide (NIPAAm) were photo grafted onto PE films by simultaneous irradiation of UV rays to obtain functional membranes. Permeabilities of MAA-g-PE and DMA-g-PE films t o glucose had maximum values at pH 9 and pH 6, respectively, where the ir respective grafted polymer chains are considered to be most expande d from the viscometric measurements of aqueous polymer solutions with a change in pH. The methylene blue (MB) permeation behavior for NIPAAm -g-PE film showed the 'on' state at 10-degrees-C and the 'off' state a t 50-degrees-C in analogy with some crosslinked thermosensitive polyme r gel samples due to the formation of the dense layers. On the other h and, DMA-g-PE films were permeable to glucose and MB at 50-degrees-C, and not at 10-degrees-C because enlarged pores were formed at 50-degre es-C due to the contraction of grafted PDMA chains. This was completel y opposite to the on-off regulation of permeation for NIPAAm-g-PE film s. These grafted PE films could possess adequate mechanical strength i n the swollen state to be of use for functional membranes.