Effect of elevated temperatures on flexural strength of hybrid Napier/glass reinforced epoxy composites

The effects of elevated temperatures on the flexural strength of hybrid Napier/glass reinforced epoxy composites were investigated. Hybrid composites laminates were fabricated using untreated, 5%, or 10% alkali-treated Napier fibres with woven E-glass fibres and epoxy resin. The composites were manufactured using a vacuum infusion process; the volume fraction of the Napier, glass fibres and epoxy resin were 24%, 6% and 70% respectively. When tested at room temperature (RT), the maximum flexural strength was recorded for the hybrid composites with the 5% alkali-treated Napier fibres. When the test temperature greater than 60 degrees C, the matrix cracking and delamination were occurred due to the temperature that approached the glass transition temperature (Tg) of the composites, which resulted in a reduction of the flexural strength. The fracture surface morphologies indicated that the 5% alkali-treated Napier fibres improved the fibre-matrix interfacial bonding of the hybrid Napier/glass reinforced epoxy composites.