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

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 δ 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

Static and dynamic mechanical properties of cotton/epoxy green composites

A study on the effect of alkaline treatment on the mechanical properties of cotton fabric reinforced epoxy composites is presented in this paper. One hour treatment of cotton fabric was performed using three different concentrations of sodium hydroxide (NaOH) solution. 1% NaOH treated fabric reinforced composites exhibited maximum improvement in tensile strength. It was concluded that the said NaOH concentration improves interfacial adhesion between the cotton fabric and epoxy resin. Moreover the morphology of the fracture surface, evaluated by scanning electron microscopy (SEM), indicated that surface treatment can yield better adhesion between the fabric and matrix, demonstrating the effectiveness of the treatment. The dynamic mechanical analysis (DMA) results revealed that alkali treated (1% and 3% NaOH) fabric composites exhibit higher storage moduli and glass transition temperature (Tg) values as compared to the untreated fabric composites. However, for all the composite specimens, the storage modulus decreased with increasing temperature (25 -100 degrees C). Tg values of 50.9, 56.7, 52.8 and 37.7 degrees C were recorded for the untreated and (1%, 3% and 5%) treated composites, respectively. The tan delta values decreased for all the composites with increasing temperature, indicating enhanced interactions between the polymer matrix and fabric reinforcement.Yüzüncü Yıl Üniversitesi - 2015 VMYOBO6

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

89-93Effect 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 δ 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

Effect of Pumice Powder on Mechanical, Thermal, and Water Absorption Properties of Fiberboard Composites

Composites were produced using medium-density fiberboard (MDF) flour with pumice powder which was mixed at various ratios by the hand lay-up technique. Mechanical properties, such as tensile and three-point bending strengths, were determined by ASTM D3039 and ASTM D790 respectively. The best three-point bending and tensile strength properties were maximum values obtained from composites containing 20wt% pumice powder (pp) and 50wt% pumice powder (pp) respectively. It is observed that the water absorption rate into the composites decreases with an increase in the pumice powder-to-ratio. The composite filled with 50wt%pumice powder absorbed the least amount of water compared to the other composites. All composites were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetry analysis (DSC). SEM images revealed a near-homogeneous surface partly free of defects and holes. However, lateral profile images showed the presence of MDF flour particles agglomerated and a considerable number of bubbles and cavities that could interfere with the mechanical properties of the composites. The results of the mechanical, and thermal properties suggested that pumice powder epoxy composites with MDF flour can increase their tensile, three-point-bending strength, and glass transition temperature for the pure MDF flour composite