Potential end of life application of African star apple shell and waste toner powder as composite filler materials

This study contributes towards showing the potential end-of-life application of common wastes namely: Waste Toner powder (WTP) and African star apple shell powder (ASASP) as low cost reinforcement for polymer composites. Herein, the effect of varying weight fractions ranging from 0 to 25 wt% for ASASP and 0–10 wt% for WTP on some mechanical properties were studied. Results showed that incorporation of both waste materials into unsaturated polyester led to a reduction in flexural properties, and a significant improvement in tensile strength, Young’s modulus and hardness of polyester. For WTP-reinforced composites, WTP1 with tensile strength, flexural strength, elongation at break and hardness value of 31.4 MPa, 109.1 MPa, 5.77% and 823 HLD, respectively, exhibited the best combination of properties. Similarly, ASASP4 with tensile strength, flexural strength, elongation at break and hardness value of 28.9 MPa, 66.9 MPa, 3.016% and 703.5 HLD, respectively, exhibited the best combination of properties for ASASP-reinforced composites. Morphological analysis showed that although fine natured, with a higher tendency to agglomerate, WTP showed better interfacial bonding and lesser particle agglomeration than ASASP. These results show that utilizing these wastes as composite filler extends their life cycle and is coherent with the principles of circular economy.