Flame retardancy of radiation cross-linked poly(vinyl chloride) (PVC) used as an insulating material for wire and cable

Abstract

Various formulations of radiation cross-linked poly(vinyl chloride) (PVC) were prepared to improve the flame retardancy for wire and cable insulation applications. Limiting oxygen index (LOI) was used to characterize the flammability of the developed formulations. The effect of different plasticizers, dioctyl phthalate (DOP), di-isodecyl phthalate (DIDP) and tri-2-ethylhexyl trimellitate (TOTM) and different flame-retardant fillers, Sb 2O 3, zinc borate, Al(OH) 3 and Mg(OH) 2 on the mechanical properties and flammability was investigated. The influence of radiation dose on the mechanical properties was minimal both at room temperature and after thermal aging for 168 h at 136 °C. The highest LOI was 39% for PVC formulations containing DOP as a plasticizer and TMPTA at absorbed doses of 90 and 120 kGy. Both DTG peak maxima and temperature for loss of 50% mass decreased with increasing irradiation dose. No influence of plasticizer type or flame-retardant filler on the thermal properties was observed.