Effect of moisture on the tensile properties of composites with bio-based fibers and matrix

Fibers and matrices made in full or part with plant-based (bio-based) materials are attracting increased attention in the composites industry on account of their potential for environmental sustainability. However, many bio-based constituents are known to be susceptible to moisture absorption and associated degradation. The objectives of this investigation are to evaluate the quasi-static tensile behavior of composites made with different combinations of jute and E-glass fibers and bio-based and synthetic (fossil-fuel based) epoxy matrices in the as-received condition and after a 24-hour soak in water at 66°C. The composites were manufactured using vacuum-assisted resin transfer molding. Fiber volume contents were determined for the composites. Tensile strength and modulus were measured on as-received and water-soaked composites. After water exposure, the jute fiber composites suffered a large reductions in modulus with either type of matrix and a large reduction in strength with the bio-based matrix but not the synthetic matrix. The E-glass composite with the synthetic matrix, which was only tested in the as-received condition, had much higher modulus and strength in comparison to the jute fiber composites.