Resin transfer molding of natural fiber reinforced composites: cure simulation

In this work hemp/kenaf fiber-unsaturated polyester composites were manufactured using a resin transfer molding (RTM) process. The fiber mats, with a moisture content of 4.3% at 50% relative humidity, were dried in the mold under vacuum to reach a moisture content around 1–2%. RTM composites with various fiber contents, up to 20.6% by volume, were manufactured. The wetting of the fibers was very good. The resin injection time was observed to increase dramatically at high fiber contents due to the low permeability of the mat. Keeping a constant mold temperature is the key to obtain fast and homogeneous curing of the part. The cure of the resin in the mold was simulated. It was shown to be in good agreement with experimental results obtained by thermal measurements at different positions in the cavity. The performance of these samples was evaluated by measuring tensile strength and flexural strength.