Glass and Aramid Fibre-reinforced Bio-based Polymer Composites Manufactured By Vacuum Infusion: A Statistical Approach to Their Physical and Mechanical Properties

This work compares the behaviour between epoxy and novel bio-based castor oil matrix composites reinforced with glass and aramid fibres manufactured by vacuum infusion. A full factorial design is applied to statistically identify the effects of polymer and fibre-type factors on the physical, tensile, flexural, and impact properties of these composites. Aramid fibre composites have lower apparent density but higher porosity and water absorption, especially if combined with a castor oil polymer. The tensile properties of aramid fibre composites are approximately 76% greater than glass fibre composites, while the epoxy matrix outperforms (up to 39%) bio-based castor oil polymer composites. In three-point bending, the epoxy system provides an increase of up to 46% in flexural properties; in contrast, the type of fibre used is not statistically significant. Regarding the impact test, the main factors and their interaction significantly affect energy properties, and castor oil glass fibre-reinforced composites have 78% more impact resistance than the other combinations. Finally, the low bulk density of castor oil polymer combined with aramid fibres provides a specific performance equivalent or superior to other synthetic composites commonly used for secondary structural applications.