A STUDY OF THE DEVELOPMENT, CHARACTERISATION AND DEGRADABILITY OF POLYESTER/NANO-LOCUST BEAN PODS ASH COMPOSITE

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Department of Engineering

ABSTRACT
This study produced locust bean pods ash, synthesized from it nanoparticles which were subsequently used for the production of polyester matrix composite. It characterized the synthesized particulates and the composite produced. It also evaluated the effects of degradation of the composite subjected to different agents on mechanical properties such as hardness, tensile, flexural and impact strength. This was with a view to determining the degradability of the composite.Scanning Electron Microscopy (SEM) was used to characterize the synthesized nanoparticles and some testsamples (composite). The minimum average Particle size of the synthesized LBPA Nanoparticles was 52.4nm, which falls within the range of 1 – 100nm, the recommended particle size required for a material to be classified as Nanomaterial. The mechanical properties of the control samples increased as the reinforcement was increased from 0%LBPA – 12%LBPA; the impact, tensile and flexural strengths increased from 0.03 – 0.37J/m, 4.30 – 6.84MPa and 10.75 – 14.17MPa, respectively. The mechanical properties of buried and weathered samples decreased with increase in reinforcement (from 0%LBPA – 12%LBPA) and exposure time (90days). The impact, tensile, flexural and hardness values of the buried samples decreased from 0.04 – 0.023J/m, 32 – 10MPa, 47.27 – 16.47MPa and 8.7 – 6.5HRF indicating 43, 69, 65 and 25% decrease,espectively. Similarly, decreases were observed in the impact, tensile, flexural and hardness values of the weathered samples from 0.05 – 0.023J/m, 28 – 12MPa, 62.13 – 8.73MPa and 11.6 – 6.6HRF indicating a decrease of 54, 57, 86 and 43% decrease, respectively. It was noted that the composite became more susceptible to degradation with increase in reinforcement. The swelling and shrinking of natural filler when exposed to natural weather and activities of microorganisms in the soil might have been responsible for the decrease in their properties. The rate of moisture absorption of the composite samples increased with increase in reinforcement; the highest value of 1.42% was obtained at 12%LBPA. The percentage by weight losses for the impact, tensile, flexural and hardness tests samples after soil burial and weathering were respectively, 0.55, 1.01, 0.09, 0.77 and 0.35, 0.93, 0.14, 0.42% after 90days of exposure. SEM examinations of the weathered and buried samples showed roughened surfaces with some voids and pits observed on the soil buried samples.