Effect of Alkalization on Mechanical and Moisture Absorption Properties of Azadirachta indica (Neem Tree) Fiber Reinforced Green Composites

The concern for the environmental pollution and the prevention of non-renewable and non-biodegradable resources has attracted researchers seeking to develop new eco-friendly green materials and products based on sustainability principles. In this experimental study, two different composites were fabricated by reinforcing untreated and alkali treated neem fibers by using polyester resin matrix. The mechanical properties such as tensile strength, flexural strength, impact strength, shear strength and moisture absorption properties of these composites were evaluated. The composites reinforced with untreated neem fibers was able to hold the maximum tensile strength of 58.38 MPa, flexural strength of 1.75 kN, impact strength of 4 kJ/m2 and shear strength of 4.6 MPa. Whereas the composites reinforced with alkali treated neem fibers was able to withstand the maximum tensile strength of 68.76 MPa, flexural strength of 2.09 MPa, impact strength of 4.8 kJ/m2 and shear strength of 5.48 MPa. Then the effect of alkalization on these properties were observed. The results indicated that these composites performed better in terms of mechanical properties and moisture absorption behaviour and the alkalization had the significant effect on these properties. Scanning electron microscopy (SEM) analysis was carried out to study the fiber matrix interfaces and analyse the structure of the fractured surfaces.