International Wood Products Journal

This study explored the effect of multiple recycling on the dimensional stability of wood–plastic composite. For this purpose, the injection moulding parameters effective on dimensional stability were first optimized based on the response surface method. Optical scanning, melt flow index (MFI), and differential scanning calorimetry (DSC) tests were used to analyse the shrinkage and deformation of recycled samples. The obtained results revealed that some recycled samples were subjected to thermal changes during the grinding and injection moulding process. The MFI and DSC results showed that the high-density polyethylene thermoplastic used in the wood–plastic composite was broken with long chains. Also, thermal changes occurred during the grinding and injection moulding process. The samples recycled three times had the highest dimensional instability (2.8% of shrinkage values). Finally, with the reduction of DSC, the semi-crystalline structure changed to amorphous, and the samples recycled four and five times had 2.7% and 2.5% shrinkage percentage, respectively.

The fibre of Grewia bicolor bark (GB) was extracted and used as reinforcement for the development fibreboards using orthophtalique unsaturated polyester (UP) as a matrix. Two methods of extraction of fibres were used, namely biological retting and chemical extraction by a sodium hydroxide solution at a 5% concentration. Chemical, Physical, mechanical, and thermal characteristics were determined using ATF FTIR, mechanical test and thermogravimetric analysis. The theoretical density of the characterized fibres was 1.30 g/cm³. The porosity decreases by 5% from the root to the leaves. The SEM analysis indicated the presence of fibrils coated with a rough sheath similar to a honeycomb cell structure. The use of NaOH in the extraction method removes the hemicellulose, pectin, wax, and lignin from the fibres. The average elasticity modulus of untreated and treated fibres are, respectively, E = 35.18 ± 2.25 MPa and E = 33.47 ± 2.35 MPa and internal bond of fibreboards are 0.98 ± 0.05 MPa and 1.06 ± 0.02 MPa.

This study comprised two focus groups exploring technical challenges and opportunities for small diameter sweet chestnut hardwood in construction. Five structural building products were designed and fabricated informed by the findings from the focus groups. Simple mobile sawmill and manual cleaving processes were used to align with regional skills and wood processing infrastructure. The building products developed were designed to provide a regenerative alternative to imported softwood timber that dominates the UK construction sector. Radially-sawn beams were found to provide high yield from small diameter roundwood and cleaving of short lengths of coppice was an effective way of producing building products from the highest proportion of short-rotation, coppiced sweet chestnut trees.

This work aimed to evaluate the effect of a closed system thermal modification process on some physical and mechanical properties of eucalypt and teak short-rotation wood. We assessed untreated eucalypt and teak (EW and TW) and thermally modified eucalypt and teak wood (TMEW and TMTW). The process was carried out at 160°C for 45 min, and we performed some physical and mechanical tests. Thermal modification reduced the mechanical resistance and hygroscopicity and increased the dimensional stability of wood. The normal density (ρ₁₂) of TMTW was reduced, but no significant effect was verified for TMEW, although it had an absolute reduction of 7%. For both conditions (untreated and thermally modified), teak was more resistant to failure (higher MOR in static bending), and no difference between the species was verified for MOE. Eucalypt wood was more resistant to compression parallel to the grain in both conditions.

Pinus wallichiana and Dalbergia sissoo wood is widely used in the construction and furniture industry in Pakistan. However, directional variability of physical properties, which can be important for wood-based industry, remains poorly documented. In both wood types, water and moisture uptake, water contact angle, and compressional strength varied significantly along the three directions. Water and moisture uptake was found significantly higher in tangential direction while water contact angle, and compressional strength was found the highest along the longitudinal direction in both wood types. Furthermore, thermal conductivity and diffusivity were found the highest along longitudinal direction however, specific heat capacity was found the highest in radial direction. Based on the results it can be concluded that although, dimensional variability was more pronounced in Dalbergia sissoo wood however, studies on site-specific variations in physical properties need further investigations for better recommendations.