Fabrication and characterisation of proton exchange membrane from sulfonated natural rubber for possible use as an alternative separator in AGM battery

Proton Exchange Membrane was fabricated from sulfonated natural rubber (NR) as an alternative to absorptive glass mat (AGM) separator for AGM battery. The separator was fabricated using chlorosulphuric acid as the sulfonating agent at 0 °C under continuous stirring. Water uptake at 25 °C ranges from 0 to 58% while at 60 °C the range is from 4 to 38%, which suggest a strong attraction between the water molecules and sulfonate moiety. The acid uptake ranges from 18 to 83% for all three membranes (A, B and C) fabricated, which proves excellent electrolyte uptake, resistance to oxidation and acid attack. The FTIR analyses, water uptake, acid uptake and Carbon-Sulphur analysis confirm that the sulfonation occurred in NR through substitution reaction on the alpha carbons. The incorporation of ZnO and SiO2, caused increase in cell size, which indicate the porous and spongy structure throughout the surface area of each membrane, which indicate promising materials for application in AGM battery.