Effect of Ionizing Radiation on Physicomechanical Properties of Surface-treated Mica-reinforced High-density Polyethylene

Abstract

Treated mica, micro-particles, were used as model fillers to study the effect of filler loading on physicomechanical properties of polymer composites. The mica particles were surface treated by silane coupling agents. The effect of gamma rays, in air up to 50 kGy, on the physicomechanical properties of such composites was also investigated. The modulus and tensile strength of filled composites increased while the strain at break decreased with increasing filler— matrix interactions. Physical crosslinking due to a network of filler particles with polymer layer supplemented radiation crosslinking of the polymer matrix. As a result, the overall crosslink density was effectively enhanced. The strength of the networks, and hence the stiffness of the composites, increased with increasing particle—matrix interactions. However, strong matrix—filler interaction caused a loss of polymer flexibility at the particle—matrix interface, resulting in a gradual decreased elongation at break of the particle-filled composites. The thermogravimetric analysis of the composites showed that the presence of treated mica in the composites reduced the rate of decomposition. The activation energy of decomposition of the composites increased with increasing filler loading. The activation energy of decomposition was also affected by the irradiation dose.