Development of hybrid fiber-reinforced vinyl ester composites for civil and automotive applications

Building and automotive sectors are accelerating the development of biodegradable hybrid natural fiber composites due to their potential for lightweight structural applications and their significant environmental benefits. This study focused on improving the mechanical properties of vinyl ester polymer composites through the hybridisation of natural fiber mats made from sisal, Indian mallow, roselle and banana fibers. Tensile, flexural, impact and hardness properties, as well as the thermal behaviour, of the hybrid biocomposites were investigated by producing five different combinations of hybrid composite laminates and varying the stacking arrangement of the natural fiber mats. The sisal/roselle fiber mat (SRM) bio-composite sample exhibited optimum mechanical properties, with higher tensile, flexural and impact strengths, as well as better thermal properties in terms of heat deflection temperature, than the other samples of double-layer sisal fiber mat (DSM), sisal/Indian mallow fiber mat (SIM) and sisal/banana fiber mat (SBM) reinforced vinyl ester composites. The vinyl ester composite reinforced with sisal/Indian mallow mat exhibited maximum impact strength and hardness values of 213 kJ/m² and 72, respectively, compared to other composites. SEM analysis of fractured samples confirmed good interfacial adhesion between the hybrid sisal fiber and the vinyl ester matrix.