Desenvolvimento de compósitos binários de polietileno de alta densidade carregados com alumina e com fibra de vidro

Abstract

In this work, composite materials made from high density polyethylene (HDPE) and alumina (Al2O3), as well as from high density polyethylene and glass fiber (GF) were developed, aiming to improve the polymer thermal and mechanical properties. The effect of each reinforcement element on the polymer properties was evaluated. The influence of some process variables such as: the surface treatment of alumina with vinyltrietoxisilane (VTES), the addition of a coupling agent, polyethylene grafted with maleic anhydride (PE-g-MA), the surface treatment of glass fiber with γ-aminopropyltriethoxy-silane, on the properties of the composites, HDPE/ Glass Fiber and HDPE/Al2O3, respectively, were also investigated. The tensile, flexural and impact properties of the obtained materials were determined. The thermal properties were evaluated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The morphology of the samples was examined by using scanning electron microscopy (SEM). The composites with treatment glass fibers with γ- aminopropyltriethoxy-silane did not obtained better properties in compare with the unloaded HDPE and it is therefore preferable to use HDPE composites with untreated glass fibers if the required performance parameters of material is to obtain better mechanical properties in tensile and flexural. The composite that presented the best properties among the composites loaded with fiberglass was HDPE / 9.8% FVnt. The treatment of alumina with VTES did not promote significant changes in thermal properties, except for an increase in thermal stability of the composite where 1.1% v/v of treated alumina was incorporated into the HDPE matrix. Regarding the mechanical properties, the treatment of the alumina did not cause changes in the Young Modulus, but increased, in relation to the untreated alumina, the tensile resistance, the flexural modulus and the resistance of the composites produced, however, only in flexural properties was observed an increase when compared to pure HDPE. Regarding the impact resistance, the treatment of alumina caused a reduction on this property. The composite that presented the best properties among the composites loaded with alumina was HDPE/3.3%Al2O3t. The use of compatibilizing agent did not show significant changes in the thermal and mechanical properties obtained, although, the morphological analysis of the composites with the use of the compatibilizing agent apparently showed that there was a better interaction between the matrix and the loads.