Effects of silane-modified Al2O3 and its hybrid filler on thermal stability and mechanical properties of ethylene-vinyl acetate copolymer/polyamide composites

In this work, the effects of silane-modified aluminum oxide (m-Al2O3) and ethylene-vinyl acetate grafted maleic anhydride (EVA-g-MAH)/m-Al2O3 hybrid fillers were studied on the mechanical and thermal properties of the ethylene-vinyl acetate copolymer (EVA)/ternary polyamide (tPA) composites. Surface modification of the pristine Al2O3 was carried out with 3-aminopropyltriethoxysilane (APTES) to enhance dispersion and compatibility of the inorganic filler into the EVA/tPA matrix. These fillers in the range of 20-40 wt% were blended into the composites and their properties were evaluated. FTIR technique was used to investigate the treated Al2O3 fillers. Experimental results showed that the thermal stability and conductivity of EVA/tPA/(m-Al2O3/EVA-g-MAH) with a ratio of 42/18/40 wt% improved significantly up to a differences of 326 degrees C and 0.178 W/m K compared to the neat EVA/tPA composite. Hybrid fillers modified with silane coupling agent and EVA-g-MAH were more effective to improve both tensile and tear strengths. The tensile strength of the EVA/tPA/(m-Al2O3/EVA-g-MAH) composite with a ratio of 49/21/30 wt% increased up to 66% compared to the neat EVA/tPA. Additionally, DSC analysis showed that the melting temperature was not significantly affected. The findings suggested that a silane modification and EVA-g-MAH compatibilizer approach for Al2O3 filler could be considered in the future research work to develop better thermally stable reinforced composites. As they showed great potentials in automotive and oil pipeline applications.