Wood-polyvinyl chloride (PVC) composites were prepared using industrial wood particles used for manufacturing three-layer particleboards. The effect of particle size (0.25–0.5, 0.5–1, 1–2, and 2–4 mm) on the mechanical properties of the composites was investigated. The effect of cross-section size (4×10, 6×15 and 8×20 mm²) of composite pieces made by an injection moulding method was also studied. Both the particle size and specimen cross-section area significantly influenced these properties. The tensile and flexural properties as well as the impact strength in general increased with increasing particle size, and decreased with increasing cross-section size.

Particles derived from milling three-layer particleboards, with sizes from 0.5 to 3 mm, were used for making composites with polypropylene by an injection moulding method. Maleated polypropylene was used as a coupling agent. The objective of this study was to evaluate the mechanical and physical properties of the composites made from particleboard and polypropylene with respect to the content of particles derived from particleboard and coupling agent addition. Properties of the composites did not differ significantly from those of composites with virgin industrial wood particles used for manufacturing particleboards. Moreover, these properties were comparable with the properties of typical wood–plastic composites with wood flour. Particles derived from milling particleboards have proved to be an effective alternative wood component of wood–plastic composites.

Biocomposites based on polylactic acid (PLA), tall wheatgrass (TWG), and hemp (H) were made by injection molding. The article discusses the impact of the agrofiller content on the composite properties, including thermal (DSC, DMA, and TG) and mechanical characteristics (tensile modulus, tensile strength, and impact strength). Generally, the introduction of a plant filler into the polylactide matrix reduced the thermal resistance of the resulting composites. Plant fillers influenced primarily the cold crystallization process, probably due to their nucleating properties. The addition of fillers to the PLA matrix resulted in an increased storage modulus across all tested temperatures compared to pure PLA. In the case of a composite with 50% of plant fillers, it was almost 118%. The mechanical properties of the tested composites depended significantly on the amount of plant filler used. It was observed that adding 50% of plant filler to PLA led to a twofold increase in tensile modulus and a decrease in tensile strength and impact strength by an average of 23 and 70%, respectively. It was determined that composites incorporating tall wheatgrass (TWG) particles exhibited a slightly elevated tensile modulus while showcasing a marginally reduced strength and impact resistance in comparison to composites containing hemp (H) components.

Wooden glued constructions require touch-free monitoring of destructive processes, especially in adhesive bonds that are most exposed to failure. The objective of the investigations was to describe failure processes in the adhesive bond of wood joints, in particular to determine their initiation, propagation, and destruction. The acoustic emission (AE) method was employed as the carrier of information about changes occurring in glued joints, whereas the numerical method was applied to determine values of distribution of tangential stresses generated in adhesive bonds. The acoustic phenomena examined were described using the AE cumulative counts. The authors analysed acoustic signals generated in loaded wooden and plastic overlap samples glued together using polyethyl methacrylate glue as well as in solid samples. On the basis of the acoustic emissions obtained, it was possible to establish characteristic places and stages of escalating structural defects generated from bonds of adhesive joints. This was utilised later on, in conjunction with results of numerical calculations, to determine correlations occurring between the AE cumulative counts and generated tangential stresses. Dependencies established in this way were used to determine characteristic points during the propagation of destructive phenomena of wood adhesive joints. The results obtained proved that it was possible to predict the development of the destruction of wood adhesive joints on the basis of observations of the increasing AE cumulative counts of acoustic signals in combination with tangential stresses determined using the finite elements method.

This study presents the results of investigations into the properties of a composite made from the commercial biopolymer with varying concentrations of ground coffee husks (CH) at 10, 30, and 50 wt%. Thermal, thermomechanical, physical, and mechanical properties were determined for the composites. Results indicate that the inclusion of CH into the polymer matrix significantly enhances the thermomechanical properties of the obtained composites, particularly in terms of storage modulus at 30 °C. The addition of coffee filler did not alter the characteristic thermal curves. Still, it reduced the thermal resistance of the composites, lowering the degradation temperature by approximately 40 °C compared to the pure polymer. Furthermore, the incorporation of CH introduced an additional stage of mass loss on the thermogravimetric curves, associated with the thermal decomposition of CH. The physico-mechanical properties of the composite depend on the content of the filler. Increasing the coffee content increases the dynamics of water absorption by the composite. It also increases the composite’s stiffness while reducing its tensile and flexural strength. The obtained results suggest that biopolymer-based composites filled with ground CH can be effectively used for manufacturing biodegradable products, with the moisture diffusion behavior indicating susceptibility to degradation that is modulated by the CH content.