Process Optimization for the Production of Bio-composite Using Waste Plastic (HDPE) and Coffee Waste (Silver Skin)

dc.contributor.advisorShimelis Kebede
dc.contributor.authorRedeat Habtamu
dc.date.accessioned2026-08-04T21:16:54Z
dc.date.available2026-08-04T21:16:54Z
dc.date.issued2026-06
dc.description.abstractThis study investigated the production and optimization of the recycled High-Density Polyethylene (HDPE) and coffee silver skin (CSS) Bio-composites as a sustainable approach for valorizing plastic and agricultural wastes. Coffee silver skin (CSS), the main by-product obtained after coffee beans roasting and has no commercial value, can be potentially used as filler to develop a sustainable Bio-composite using recycled High-Density Polyethylene (rHDPE) as polymer matrix. Chemical treatment of CSS significantly improved cellulose content, structural order, thermal stability, and surface morphology, providing a high-quality reinforcement material. In this research work, CSS was grounded and fractionated in to three different sizes (100μm, 300μm, and 500μm) with varying filler ratio (10, 20, and 30wt.%), the Composites were fabricated through compounding and consolidation processes. Fabrication process was optimized for tensile strength of the resulted composite, achieving a maximum of 5.99MPa, under conditions of a particle size of 285.82μm, 10.44% of filler ratio, and a temperature of 175.97℃. Under this optimized processing conditions composite from treated CSS achieved 6.71MPa of tensile strength. Thermal, morphological and physicochemical properties of the bio-composite also investigated. The results show that the fabricated composite own suitable for replacing the conventional building material by sustainable Bio-composite through waste valorization align with the principles of circular economy.
dc.identifier.urihttps://etd.aau.edu.et/handle/123456789/8798
dc.language.isoen
dc.publisherAddis Ababa University
dc.subjectCSS
dc.subjectSustainable Bio-composite
dc.subjectCircular Economy
dc.subjectHDPE
dc.subjectOptimization
dc.subjectTensile Strength
dc.titleProcess Optimization for the Production of Bio-composite Using Waste Plastic (HDPE) and Coffee Waste (Silver Skin)
dc.typeThesis

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