Effect of alkaline treatment on mechanical properties of voile fabric reinforced epoxy composites

Abstract

Effect of alkali treatment on the mechanical properties of epoxy composites reinforced with alkali-treated voile fabric has been studied. The voile fabric is treated with different concentrations of NaOH solution (1% and 3% ) for 1 h at 20 ± 2 °C. The epoxy-based composite obtained by reinforcing the alkali-treated fabric is evaluated for its tensile strength, and dynamic mechanical properties. Composite reinforced with 3% NaOH solution treated fabric shows significant improvement in tensile strength (~32.72%). This implies that the concentration of NaOH treatment greatly influences the interfacial adhesion between the voile fabric and the epoxy. Results of dynamic mechanical analysis show an increase in the storage moduli of the composites reinforced with 1% and 3% NaOH treated fabric as compared to untreated composites at 20 -100 °C. However, for all the composites, the storage modulus decreases with the increase in temperature with a significant fall in the temperature range 25 - 100 °C, indicating that the incorporation of voile fabric in epoxy matrix unconcluded reinforcing effects appreciably at higher temperatures. The loss moduli of untreated and treated composites decrease with the increase in temperature. The glass transition temperatures of the untreated and treated (1% and 3% NaOH) composites are found to be 35.36 °C, 35.81 °C, and 30.55 °C respectively. For all the composites, the value of tan <i>δ </i> decreases with the increase in temperature which indicates the level of interactions between the polymer matrix and the reinforced fabric. The fractured surface of composites is observed using SEM, which indicates the surface modification of the voile fabrics with alkali treatment and subsequent improvement in fibre-matrix adhesion.