Effect of microcrystalline cellulose on the mechanical properties of flax reinforced methylmethacrylate and urethane acrylate composites

Many structural applications are attracted to natural fibre-reinforced polymeric composites due to their eco-friendliness, recyclability, and cost-effectiveness. While significant progress has been made, their interface compatibility with the polymeric matrix is still challenging. Therefore, the present study proposed a method for improving the mechanical and dynamic mechanical performance of flax-reinforced novel methylmethacrylate (Elium^®) and urethane acrylate (Crestapol^®) composites. The technique involved the dispersion of microcrystalline cellulose (MCC) in the matrix at different weight percentages (0.5–0.75%) to improve the fibre/matrix interface. Flax/Elium^® (FE) and flax/Crestapol^® (FC) composites with varying weight percentages of MCC were manufactured using the vacuum infusion method. The resulting improvements in mechanical and dynamic properties were evaluated through in-plane shear (± 45° tensile), flexural, short beam shear, and dynamic mechanical analysis (DMA). The effects of MCC on these properties of flax/Elium^® were compared to those of flax/Crestapol^® composites. The addition of MCC improved the in-plane shear strength (FE: 13–20%, FC: 10–17%), flexural strength (FE: 6–13%, FC: 13%) and interlaminar shear strength (FE: 9–17%, FC: 10–20%). Also, FE composite showed 7–11%, 10–14% and 10–17% higher in-plane shear, flexural and interlaminar shear strengths, respectively, compared to FC composites. The DMA results confirmed the positive effect of Elium^® resin and MCC on the dynamic storage and loss modulus.