Characterization and evaluation of a novel renewable plant product (RPP) gum as a flame retardant additive in chloroprene and natural rubber

Abstract

With an objective to search a new class of polymer / rubber additives specially flame retardant (FR) from the plant origin as a suitable substitute of conventional FR additive Sb2O3, an attempt was made to explore the effectiveness of a renewable plant product (RPP), collected as a gum from an Indian local plant, Spondias dulcis, Anacardiaceae family, as a flame retardant additive in chloroprene (CR) and natural rubber (NR) vulcanizate. FTIR spectra were recorded and the relevant functional groups present in RPP gum were assigned. TGA and DSC were registered to study the thermal response of the gum. The crystalline behaviour was judged by XRD followed by evaluation of surface elemental composition by EDX. Compound formulations containing 10 wt% of RPP were prepared with CR and NR separately along with the control with and without Sb2O3. Flame retarding property of all the filled vulcanizates was monitored by limiting oxygen index (LOI) test and some tensile properties viz., 200, 300 % modulus, tensile strength and elongation at break are measured to study the effect of RPP on physico-mechanical properties of vulcanizates. In a preliminary study LOI value was found to increase by ~17 and ~12 % for CR and NR respectively in the formulations containing RPP in comparison with that of the control without Sb2O3. The flame retarding property of RPP was justified with TGA and DSC results. No significant change of the tensile properties was observed on incorporation of RPP in the formulations.