The best approaches to minimizing resource scarcity, removing valuable waste streams, and re-establishing a circular economic chain of recycled thermoplastics are to cascade them into product life cycles and their valorization combined with sustainable raw materials. As one part of this goal, WPC was formulated from three recycled PE plastic wastes: linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and underutilized EHB. The chemical composition of EHD, chemical structure, crystallinity, melting and crystallization points, residual metal additives, and polycyclic aromatic hydrocarbons (PAHs) of recycled PE were investigated using standard chromatographic and spectroscopic methods such as HPAEC-UV/VIS, FTIR, DSC, GC/MSD, and XPS. The properties of WPC formulations from different compositions of bamboo particles (BP) as dispersed phase, individual recycled PE plastics, and equal melt blend (EM) as polymer matrix were investigated extensively and measured with a known standard. These comprised tensile strength (TS), modulus of elasticity (TM), flexural strength (FS), modulus of rupture (FM), and unnotched impact strength (UIS). It also included the effect of various alkaline surface treatment ranges on the interface surface interaction. The results show improved mechanical properties for all blending ratios of surface-treated BP, which resulted from better encapsulation in the polymer matrix. Despite its inherent immiscibility, WPC formulation from equal melt blending revealed unusual properties compared to separate phase blends, which is attributed to thermally induced cross-linking. This implies that melt blending of the weakest and cheapest recycled LLDPE with relatively cheap recycled MDPE and HDPE improves the properties of the blend, particularly toughness, while simultaneously retaining some of their properties.

The sudden availability of Italian stone pine (Pinus pinea L.) wood due to the infestation of pathogenic fungi and insects highlighted the need to promote its use as a short supply chain resource in Italy and other Mediterranean countries. However, the durability of stone pine sapwood must be enhanced if outdoor use is to be considered. The impregnability of stone pine wood was studied following the standard EN 351-1:2008, using immersion, vacuum, and high-pressure methods with natural waxes and organic solvent-based and copper-amino-based preservative solutions. The efficacy of the impregnation was determined by calculating the kilos of preservative absorbed per cubic meter of wood and by measuring the penetration depth of the preservative. Thermal modifications were carried out using five different maximum temperatures, and their efficacy was determined by measuring the mass loss and color change. Subsequent to thermal treatments, the wood was exposed to a water-vapor-saturated atmosphere, and the increase in mass was calculated for different periods. Stone pine and Scots pine sapwoods showed similar response to the treatments with the exception of soaking impregnation methods where stone pine showed higher uptake, in particular when Silvanolin was used. Our investigation shows that stone pine can be a suitable short supply chain resource in Italy that, when impregnated, could be tested for outdoor use, exactly as is the case with Scots pine.