Reinforcement of polymethyl methacrylate with silane-treated zinc oxide nanoparticles: fire retardancy, electrical and mechanical properties

Abstract

Polymethyl methacrylate (PMMA)/zinc oxide (ZnO) composites were prepared using melt mixing process. A nano ZnO-treated with aminopropyl triethoxysilane (APTS) was used as reinforcing particles. PMMA composites were obtained with different ZnO loadings of 0, 0.5, 1 and 2 parts by weight. This research was focused on determination of the influence of different loadings of silane-treated ZnO particles on the morphology, electrical, mechanical and flammable properties of the PMMA composites. Addition of ZnO to the PMMA composite was observed to enhance the thermal properties and char formation. The results from cone calorimeter showed 21% reduction in the peak heat release rate for the composite loaded with 1.5 wt% of ZnO as compared to that of neat PMMA. The surface resistivity, volume resistivity and EMI shielding properties of the composites as a function of ZnO loading were estimated. The results showed that the surface and volume resistivity of the composites reinforced with ZnO particles decreased and the EMI shielding increased almost linearly with increasing ZnO volume content. However, the tensile strength of the composites showed a slight decrease with increase in ZnO content. The SEM micrographs and AFM images showed dispersion of ZnO particles in the PMMA matrix. The nanoparticles were distributed evenly on the surface. Nevertheless the pockets of agglomerates could be seen at higher ZnO loading level.