Caracterização de compósitos de polietileno de baixa densidade/atapulgita e avaliação dos efeitos do tratamento ácido da carga sobre as propriedades do compósito.

Abstract

The mechanical properties of low-density polyethylene composites densities with different conventional fillers (talc and calcium carbonate) and unconventional (atapulgite treated with mineral acids and untreated), were studied. The evaluated properties were the tensile strength, flexural strength and impact strength. The hardness and the degree of crystallinity of the polymer and its composites. The experimental results showed that atapulgite, due to its fibrous constitution, acted as a charge reinforcement for polyethylene, which was evidenced by the increase in resistance to the composite traction with up to 30% by weight of incorporated filler. Comparisons made with low density polyethylene composites using such as talc and calcium carbonate, classified as inert, have shown that only hardness and impact resistance showed an increase, being that the composite that presented the highest energy absorbed in the impact test was or 20% by weight of the filler (talc) incorporated. The effect of treatments of atapulgite with hydrochloric and nitric acids, and it was verified, after treatment, increased porosity of the load and increased resistance mechanics of the composite, attributed to the phenomenon of "mechanical coupling" and greater physical adsorption of the charge to the polymer. Treatment with nitric acid was which promoted a greater mechanical resistance to the composites, and the effect of the The addition of fillers in polyethylene showed that only 10% by weight of there was an increase in the degree of crystallinity and that, for the other percentages (20 to 40% by weight), the charges acted as inhibitors of crystallization.