Effect of fly ash on thermal stability, flammability, oil resistance and transport properties of chlorinated styrene butadiene rubber composites

Abstract

Fly ash (FA) can be used as a filler in rubber vulcanizates to get rid off their waste. Polymer composite based on chlorinated styrene butadiene rubber (CSBR)/containing varying amount of FA composites has been developed by melt compounding followed by dicumyl peroxide vulcanization. The influence of increased loading of FA on the cure characteristics, mechanical properties, thermal stability, flame and oil resistance has been investigated. The increase in FA loading in CSBR matrices has been found to accelerate the curing process up to 37% compared to unfilled sample. The uniform distribution of FA in CSBR has been confirmed by scanning electron microscopy, which also explained the improved mechanical properties, flame and oil resistance of the composites. The diffusion rate of aromatic hydrocarbon solvents through the composite film is minimum for composites with 30 phr of filler and the rate is increased with increasing the filler content. Activation parameters are estimated and the molecular mass is calculated using Flory–Rehner theory. The sorption data are used to estimate the enthalpy, entropy and free energy of mixing. Mechanical properties such as tensile strength, modulus and hardness of the samples decreased after immersion in ASTM oil and the decreasing trend is lower for 30 phr FA-filled samples.