Hydrogel coating of RVNRL film by electron-beam irradiation

The tackiness properties of radiation-vulcanized natural rubber latex (RVNR L) film surfaces coated by various monomers were investigated in order to d efine the suitable hydrogels which reduce the tackiness of the film. In thi s context, different types of monomers, namely, N-vinyl-2-pyrrolidone (NVP) , N,N-dimethylaminoethylamide (DMAEA), acrylic acid (AAc), n-butyl acrylate (n-BA), and 2-hydroxyethyl methacrylate (HEMA) as well as the monomer mixt ures were tried with varying degrees of success. Coating the RVNRL film wit h 80% HEMA/20% n-BA by irradiation at 80 kGy using a low-energy electron be am gave a remarkable reduction in the surface tackiness of the RVNRL film. Several other attempts were made such as priming the RVNRL film with acid a nd aluminum sulfate prior to coating, mixing the aluminum sulfate into the monomer mixtures, and dipping the partially wet RVNRL film into the monomer to enhance the wettability of the monomers with the film. The photomicrogr aphs taken illustrate that the decrease in tackiness with the coating is du e to the increase of the surface roughness at an 80-kGy irradiation dose. T he studies also revealed that the reduction in the contact angle and the in crease in water absorption of the RVNRL film after irradiation are due to t he formation of the hydrogel layer. (C) 1999 John Wiley & Sons, Inc.