Synthesis and characterization of novel melt-processable ionomers based onradiation induced styrene grafted natural rubber

Graft ionomers based on natural rubber were prepared by sulfonating radiati on induced styrene grafted natural rubber (SGNR) with acetyl sulfate reagen t, followed by the neutralization of the precursor acid using methanolic zi nc acetate. The modified natural rubber was characterized using spectroscop ic techniques such as Xray fluorescence (XRFS), Fourier transform infrared (FTIR), Fourier transform NMR (FTNMR), thermo-gravimetric analysis (TGA) an d also by the evaluation of mechanical properties. The IR studies of the io nomers reveal that the sulfonate groups are attached to the Para-position o f the benzene rings of the polystyrene blocks. NMR studies give credence to this observation. Thermal analyses show that incorporation of ionic groups makes profound improvement in the thermal stability of SGNR. The presence of ionic groups results in enhancement of mechanical properties as well as retention of properties even after three cycles of processing at 150 degree sC.