Physical and Mechanical Characterisation of Recycled Pet/Coconut Shell Powder Composite for Assistive Device Applications
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This study investigated the mechanical and physical properties of recycled polyethylene terephthalate (PET) reinforced with coconut shell powder, with the aim of assessing its suitability for assistive device applications such as crutches. Composites were produced by mechanically mixing PET and coconut shell powder at various weight fractions (0–25%) followed by compression molding. Physical tests conducted included density and water absorption measurements, while mechanical evaluation comprised of tensile, flexural, compressive and impact strength tests. The results showed that the density of the composites increased from 1.18 to 1.32 g/cm³ as the reinforcement increased, reflecting the higher density of coconut shell powder compared to the PET matrix. Water absorption also increased with reinforcement, with sample E recording above 50 % absorption after prolonged immersion, while the unreinforced sample absorbed less than 10 %. This behavior was linked to pores created at higher fibre content. Tensile strength ranged from 2.53 to 9.07 MPa, with the optimum performance at 15 % reinforcement (sample D). Young’s modulus varied from 2.85 MPa in the control to 159.09 MPa in the highest reinforcement sample, indicating improved stiffness with reinforcement. Flexural results showed modulus of elasticity values between 2205.5 and 4135.3 MPa, and modulus of rupture values from 18.9 to 36.5 MPa, again with sample D showing the best performance. Compressive strength ranged from 0.60 to 1.48 MPa, with the highest value at 15 % reinforcement. Impact strength increased from 0.2 J in the unreinforced sample to 2.5 J in sample D. These findings demonstrate that moderate reinforcement with coconut shell powder enhances both stiffness and toughness without significantly increasing weight. The developed composite showed improved mechanical properties that make it a candidate material for lightweight assistive devices. Its low density, reasonable strength and improved impact resistance suggest potential for use in crutch production, contributing to comfort, user safety, and sustainable material application
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