Polyethylene-coffee husk eco-composites for production of value-added consumer products
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Jaramillo Zapata, Leyla Yamile | 2021
The annual worldwide production of coffee exceeds 10 million tons, and more than 90% of this production is
waste, including the husk. On the other hand, plastic consumption increases every year, and sustainable alternatives
are necessary to decrease it. This work arises to solve these two problems, and seeks to produce products at an
industrial level from polyethylene/coffee husk eco-composites. Both Low Density Polyethylene and High Density
Polyethylene were used, and the amounts of coffee husk added as filler were 20 and 40 wt%. The composites were
characterized by different morphological, thermal and mechanical techniques. Scanning Electron Microscopy
images showed husk particles embedded in the polymer matrix, but with some gaps between the polymer and
the filler, because no compatibilizer agent was used. The addition of large amounts of natural filler negatively
affected the tensile strength and elongation at break, but increases eco-composites crystallinity, and hence, their
Young modulus and hardness. The industrial applicability of the eco-composites was verified through the
production of five different consumer products by extrusion and injection processes, using mixtures with 40 wt%
coffee husks. All products were obtained without significant defects. If only 3.25 wt% of the polyethylene products
produced each year in Colombia did so with the eco-composites developed in this work, all the coffee husk
produced in the country would be used, and the emission of about 5.390 million m3 of greenhouse gases would
be avoided.
Keywords: Waste valorization, Eco-composite, Natural fibers, Value–added products, Coffee husk, Polyethylene
LEER