Characterization Of The Mechanical Proper Ties Of Unsaturated Polyester Reinforced With Varying Fraction Of Particulate Groundnut Shell

ABSTRACT

The objective of this study is to produce and determine the mechanical properties as well as water absorption characteristics of unsaturated polyester-groundnut shell particle composite. The aim of the study with varying weight of groundnut shell particle is to find the composite with optimum mechanical properties. Groundnut shell of undersize particle of 300 microns was introduced at different percentages into the unsaturated polyester resin. Composites were produced at 2%, 4%, 6%. 8% and I 0% volume fraction of groundnut shell particle tillers and the polyester was cast neat at 0% groundnut shell particle filler which served as the control. Mechanical properties of the composites such as tensile properties (tensile stress, tensile strain, Young's modulus, tensile strength and percentage elongation at fracture), flexural strength and hardness were experimentally determined in the engineering laboratories using Double cell Universal Instron machine (Instron 3369) at a cross head speed of 5mm/min and a load cell capacity of 50KN, Rockwell hardness testing machine (HRA 60) and Taber abrasive machine at 150 RPM. Water absorption test was also carried out on the samples. The tensile test specimen preparation and testing procedures were conducted in accordance with the ASTM. Results of the mechanical property tests showed increase in hardness, flexural strength and Young's modulus. The tensile prope1ties showed: that at I 0¾GSF the highest tensile strength of 783MPa compared to the control of I 0.84155 MPa, the cast composite with I 0wt¾ GSF had the best tensile modulus of 783MPa. Increasing the volume fraction of groundnut shell particle filler from 0% to 2%, 4%, 6% and 8% led to decrease in tensile strength from I 0.84 I 55MPa to I 0.29971 MPa of the reinforced composites. The wear property of the composite was enhanced at 4wt% and had the best wear index of 1.04 compared to the control of 0.251.The polymer composites showed irregular pattern in their water absorption prope11y with 2wt¾GSF having the highest water absorption prope11y and 4wt% having the poorest water absorption property. It was deduced from the study that, the groundnut shell reinforced polyester composite will perform in engineering areas of application that require mild strength such as in window frames of automobiles, casing of electrical appliances, and floors of airplanes. Also, Surface coating of groundnut shell particle filler could be used to improve its adhesion to the polyester matrix in order to enhance the mechanical properties of the composites for other engineering applications.