Dehulled coffee husk-based biocomposites for green building materials

Abstract

In this work, coffee husk (CH) was used as a reinforcement for polypropylene (PP) to fabricate bio-based composites by compression molding. The effects of three different ratios of CH/PP (70:30, 80:20, 90:10 wt%/wt%) and densities (0.5, 0.75, and 1.0 g cm−3) on the mechanical properties, flame retardancy, water stability, sound, and thermal insulation were studied. Results revealed that the 1.0 g cm−3 composite at 80:20 ratio had the highest tensile and flexural strength (24.5 and 21.5 MPa, respectively). With increase in density, the water stability and flame retardancy of the composites improved. The 1.0 g cm−3 80:20 ratio CH/PP composites had the highest sound absorption coefficient of 0.9 and thermal insulation coefficient of 51.8 mW mK−1, which is within the acceptable range of standards for insulation materials according to TS 805 EN 601 standards. CH/PP composites exhibit favorable properties to be used in false ceiling and insulation panels.