Wood–plastic composite (WPC) is an environmentally friendly and cost-effective materials, while the high density and suboptimal mechanical properties of traditional WPC limit their broader applications. In this study, a wood fiber/polypropylene composite foam (WPCF) is fabricated via chemical foaming enabled by Nano-polytetrafluoroethylene (PTFE). Compared with the unmodified wood fiber/polypropylene composite foam, our developed WPCF demonstrates a 37.69% increase in cell density and a 29.45% decrease in cell size with uniform cell distribution. The fine cell structure of WPCF is attributed to the improved crystallization and suitable viscoelastic behavior due to the addition of nano-PTFE. As a result, WPCF demonstrates superior mechnical performance. When the PTFE content was 1 wt%, WPCF shows a tensile strength of 9.41 MPa, a flexural strength of 22.63 MPa, and a improved impact strength of 5.27 kJ/m², which is 47.65, 33.12, and 76.23% higher than those of unmodified WPCF. Given to the mechanical robustness and low density of WPCF, the as-prepared high-performance wood fiber/polypropylene composite foam is a promising alternative as a green and sustainable material to traditional wood in construction, furniture, and packaging sectors.

This study investigated the development of thermoplastic composites by incorporating crude lignin extracted from coir fiber waste, into poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polymer. The extracted crude lignin was blended with PHBV as a matrix, and spent coffee grounds (SCG) were used as biofillers. SCG were chemically modified through sodium hydroxide (NaOH) treatment and maleic anhydride (MA) grafting to enhance their compatibility with the PHBV/lignin blend. Raw and modified SCG were characterized for their functional, morphological, and thermal properties before being incorporated. Thermoplastic biocomposites were prepared via melt compounding and compression molding and evaluated for water barrier, morphological, mechanical, and thermal properties. Results showed that MA-grafted SCG significantly enhanced PHBV-lignin properties, increasing tensile strength by 23.7% and thermal stability by 11.9% compared to the control matrix. Optimal performance was observed at 5% MA-grafted SCG filler loading. However, higher SCG concentrations (7%) led to filler agglomeration, negatively affecting the material properties. This research demonstrated the potential of utilizing agricultural and food waste to create high-performance thermoplastic composites for future applications in biodegradable packaging, contributing to the advancement of a circular economy and environmental sustainability.

This study uses a rotomolding procedure to produce hollow cubes made of linear low-density polyethylene (LLDPE) and coconut fibers (CF). The purpose is to investigate the effect of different CF content (0, 5, 12.5, and 20 wt%) and size (100 and 50 mesh) on composite properties. As the CF content rises, the density of all composites decreases due to an increase in material porosity, a result of poor adhesion between the fiber and LLDPE. Impact strength reduced as the content of CF increased, except for the composite with 5 wt% of CF and 50 mesh size. The ineffective adhesion between coir fibers and LLDPE, along with the presence of voids in the matrix, caused the mechanical properties to deteriorate as the CF content increased. The flammability test revealed that all samples dripped. The neat LLDPE sample deformed, whereas the LLDPE/CF composites maintained their shape. This behavior suggests that CF plays a structural role in burning composites. Maleic anhydride-grafted polyethylene (MAPE), calcium stearate, and magnesium stearate additives did not contribute to reducing the composite’s porosity. MAPE was the only additive that did not reduce the elastic modulus of composites.