Application of Modified Burn-Off Testing in Sustainable Marine Composites

Natural fibers, such as hemp and flax, are sustainable materials that offer biodegradability, low density, and lightweight advantages. These properties have led to their increasing application in the automotive and construction industries, with marine applications also showing promising potential. However, cellulose-based fibers have inherent challenges, including moisture absorption at ambient conditions and interfacial adhesion issues between fibers and the polymer matrix, necessitating optimized fabrication techniques. In hemp fiber composites, increasing the fiber volume fraction results in higher moisture absorption, which can lead to degradation in mechanical properties. Since
composite structures must maintain consistent glass content as per design specifications, it is crucial to investigate the effects of moisture absorption on glass content in hemp- and flax-based natural fiber composites. However, due to the boiling point variations between cellulose fibers and synthetic resins, conventional burn-off test methods are not applicable. Thus, an adapted version of ASTM D3171 was employed in this study to accurately evaluate the fiber content of hemp and flax composite materials using a modified burn-off test.