KINETICS OF DIFFUSION OF STYRENE MONOMER CONTAINING DIVINYL BENZENE THROUGH VULCANIZED NATURAL-RUBBER

Diffusion and sorption of styrene monomer containing divinyl benzene a s crosslinker through vulcanised natural rubber were studied in a temp erature range of 25-45 degrees C. this study is the primary step in th e preparation of an interpenetrating network (IPN) based on natural ru bber (NR) and polystyrene (PS) by the sequential technique, where NR i s swollen in styrene monomer and its crosslinker and initiator, which is then polymerised in situ. The mechanism of diffusion was analysed a nd was found to follow an anomalous trend. The influence of the nature of crosslinks and crosslinking density of NR on the transport propert ies was examined. The diffusion coefficient was calculated and was fou nd to be concentration dependent. Arrhenius parameters for diffusion a nd permeation processes and other thermodynamic parameters of sorption were estimated. The influence of the cure system, the nature of cross links, crosslink density, and temperature on the diffusion process wer e examined in detail. In the presence of crosslinker, the monomer upta ke was lowered, whereas an increase in temperature activated the diffu sion process. Finally, the experimental sorption results were compared with theoretical predictions.