Mechanical properties of gamma irradiated TiO2NPs/MWCNTs/LDPE hybrid nanocomposites

Abstract

This work investigates the impact of ϒ-irradiation on the mechanical properties of titanium oxide nanoparticles (TiO2NPs)/multi-walled carbon nanotubes (MWCNTs) hybrid low-density polyethylene (LDPE) nanocomposites. Hybrid LDPE nanocomposite films prepared using melt mixing technique were exposed to different doses of ϒ-radiation, ranging from 5 to 50 kGy. The tensile strength was diminished after TiO2NP or MWCNT addition, then increased with a further increase in the carbon nanotube (CNT) content. This behavior can be ascribed to stress transfer between the filler and the LDPE network. Besides, the tensile strength was enhanced after exposure to a dosage of 5 and 25 kGy of ϒ-radiation, then followed by a decline when exposed to 50 kGy, especially in the case of hybrid films due to the degradation and cross-linking of LDPE chains caused by ϒ-radiation. Because of the absorbance and antioxidant effects of CNTs, the CNT addition retarded the degradation of LDPE networks and decreased the catalytic activity of TiO2NPs to activate degradation upon radiation exposure. Therefore, the tensile strength was retained after exposure to a dose of 50 kGy of ϒ-radiation, especially in case of less TiO2NPs and more CNTs filled hybrid films. Furthermore, the % of the total elongation at break is decreased after incorporating MWCNTs. The % of the total elongation at break after exposure to a dosage of 25 kGy was reduced as a result of chain scissions and molecular weight decrease. Young’s modulus of the irradiated composites was lower than without irradiation. This effect was more significant for neat LDPE and TiO2NPs filled LDPE films, whereas MWCNTs had some stability effects on the nanocomposites.