A Comparison of Commercial Carbon Fiber and Flax Fiber Under Mechanical Stress and Heat Fatigue

This study evaluates the mechanical viability, impact resistance, and thermal resilience of a sustainable flax fiber composite as an alternative to traditional carbon fiber in performance sports equipment. A 3-point bending apparatus was created, and baseline and post fatigue specimens were tested under both room temperature and extreme heat. Quantitative results revealed carbon fiber had the highest absolute stiffness of 24.02 gigapascals, at room temperature, post-impact, it lost 14 percent of its stiffness in its flexural modulus due to microfracturing. Flax experienced a 24.1 percent decline in its modulus; however, most notably at elevated temperatures, the flax was optimized, experiencing matrix post-curing from the heat, resulting in a 257.2 percent stiffness increase, a significant change in comparison to carbon fiber. These findings demonstrate that while flax doesn’t have the absolute stiffness of carbon fiber, it offers a reliable, sustainable alternative with similar stiffness retention and unique heat optimization for high-performance sports use.