Effect of Recycling Cycles on the Mechanical and Damping Properties of Flax Fibre Reinforced Elium Composite: Experimental and Numerical Studies

This manuscript deals with the effects of recycling on the static and dynamic properties of flax fibers reinforced thermoplastic composites. The corresponding thermoplastic used in this work is Elium resin. It's the first liquid thermoplastic resin that allows the production of recycled composite parts with promising mechanical behavior. It appeared on the resin market in 2014. But until now, no studies were available concerning how it can be recycled and reused. For this study, a thermocompression recycling process was investigated and applied to Elium resin. Flax fiber-reinforced Elium composites were produced using a resin infusion process and were subjected to different thermomechanical recycling operations. For each material, five recycling operations were carried out on the raw material. A total of 10 different materials were investigated and tested by means of tensile and free vibration tests to evaluate the effect of recycling on their behavior. In addition, a finite element model of the dynamic problem was developed to evaluate the loss factor and natural frequencies regarding different cases. The results obtained show that the failure tensile properties of Elium resin as well as flax fiber reinforced composites decrease during recycling operations. Conversely, recycling induces a rise in the elastic modulus. Moreover, improvement in the dynamic stiffness was observed with recycling operations. But repeated recycling appeared to have negligible effects on the loss factor of the recycled materials. The results obtained from the experiment and the numerical analyses were in close agreement.

Automated summary

This study investigates the effects of recycling on the properties of flax fiber reinforced thermoplastic composites, specifically focusing on Elium resin. The findings indicate a decrease in failure tensile properties during recycling operations, although there is an increase in elastic modulus. Dynamic stiffness shows improvement with recycling, while the impact on the loss factor seems to be minimal. The experimental and numerical results are closely aligned.