Improvement of physicochemical properties of natural rubber and polyvinyl alcohol blends by radiation vulcanization

Variable compositions of natural rubber latex (NRL) and polyvinyl alcohol (PVA) have been blended. The contents of PVA in the blends were varied from 0.5 phr to 3.0 phr and the total solids contents of NRL was fixed to 50%. The blends were irradiated at different irradiation doses (0-20kGy) in the presence of normal butylacrylate (n-BA). The permanent set; swelling ratio and elongation at break point of the blended films at all compositions decrease with the increase of radiation doses whereas increase is observed in cross-linking density, gel content, tensile strength and modulus. Sharp changes of all the properties were observed between 3-5kGy radiation doses. On the other hand, at higher radiation doses, >= 5 kGy, the permanent set, swelling ratio, gel content did not show any appreciable change whereas cross-linking density, tensile strength, modulus and elongation at break point are changed. The maximum cross-linking density of blend is observed with 2.0 phr PVA at 12kGy radiation. The highest value of modulus and tensile strength of the same blend are found at 10kGy and 5 kGy respectively. Blends with 2.0 phr PVA for all compositions proved to be optimum for improving varies properties at 5-12kGy radiation doses.