Absorção de água em materiais compósitos de fibra vegetal: modelagem e simulação via CFX.

Abstract

Studies in polymer composites reinforced with vegetable fiber show that they are enough sensitive to influences from environmental agents such as water and temperature. The moisture causes degradation of the mechanical properties of natural fiber reinforced composites to a large extent when compared to synthetic fiber reinforced composites. This is a consequence of the higher moisture absorption, and the hydrofilic nature of the natural fiber. In this sense, the purpose of this work is to study theoretically the water absorption in unsaturated polyester composites reinforced with caroá natural fiber (Neoglaziovia variegata) at the temperatures 25, 50 e 70°C. The composite had a weight composition of 30% caroá and 70% unsaturated polyester resin and dimensions of 20x20x3 and 20x20x6 mm3. Results of the average moisture content and moisture content distribution during the absorption process are presented and analyzed. Comparison between numerical and experimental data of the average moisture content presented good agreement. It can be concluded that the water absorption rate is faster in the vertex region of the composites, mainly at increased temperature.