Water Absorption in Sisal Fiber Reinforced-Polymeric Matrix Composites: Three-Dimensional Simulations and Experiments

Abstract

In this work was conducted a theoretical and experimental study of water absorption in polyester matrix composites reinforced with sisal fiber at temperatures of 25, 50 and 70°C. A fiber content 44.6% sisal fibers, and 55.4% polyester matrix were used in the manufacture of the polymer composite. The dimensions of the composite were 20x20x3mm3 and 20x20x6mm3. Water absorption tests were conducted by immersion of the samples in a distilled water bath and the water uptake calculated by weight difference of the samples in the dry and wetted condition at different elapsed time. A three-dimensional mathematical model was developed to predict mass transfer during the water absorption inside the parallelepiped solid. Results of water absorption kinetic and moisture content distribution inside the composites showed the more favorable areas which presents delamination problems due the weakness of the fiber-matrix interface and consequently, reduction in the mechanical properties. It was found that the high water bath temperatures accelerate the absorption process and that the water absorption of the sisal reinforced polymer composite with 3 mm of thickness was faster than the with 6 mm of thickness.