PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 11, Number 3, 2025
However, MDF produced with 100% recycled fibres exhibited a dramatic decrease in physical and mechanical properties, despite a reduction in formaldehyde content. Compared to MDF with virgin fibres, the internal bond strength of recycled MDF statistically decreased at all substitution ratios. In contrast, other properties were comparable at 15% or 25% rates for fibres produced using the mTMP process. Finally, MDF containing mTMP fibres showed similar density profile values, slightly higher than MDF with ST fibres. “Flammability and mechanical performance of fibreboards based on wool fibres and extracellular polymeric substances recovered from wastewater sludge”, Mufidatul Ula, Tan Minh Le, Yuemei Lin, Mark C.M. van Loosdrecht, Debes Bhattacharyya, Krishnan Jayaraman & Nam Kyeun Kim, Materials Today Sustainability , 31, September 2025, 101210. This study investigates the influence of extracellular polymeric substances (EPS), recovered from wastewater sludge, on the flame-retardant and mechanical properties of wool-based fibreboards. The thermal properties of wool, resin, and EPS were analysed using thermogravimetric analysis and differential scanning calorimetry to determine manufacturing parameters and assess their impact on the thermal decomposition of the fibreboards. A specialised fibreboard manufacturing setup, incorporating a drum mixer, tube blender, and hot press, was developed to fabricate the composite boards. Results indicate that increasing the hot-pressing time enhances both flexural and internal bond strength. The incorporation of EPS significantly improves the internal bond strength compared to fibreboards without the biopolymer. Moreover, the combined effects of wool and EPS promote effective char formation and lead to a V-0 rating, showing self-extinguishing behaviour in vertical burn tests. Cone calorimeter analysis reveals that while EPS contributes to a reduction in the heat release rate, its effect reaches a saturation point. However, the fire growth index, along with barrier and protective effect values, demonstrates that EPS effectively mitigates fire spread and propagation. These findings highlight the potential of wastewater-derived EPS as a sustainable additive for enhancing the fire resistance and mechanical integrity of wool-based fibreboards. “Shear performance of single-layer unidirectional strand board (USB): modified testing methods”, Ahmadreza Ghazanfari, Lukas Malzl, Maximilian Pramreiter, Roman Myna, Johannes Konnerth & Benjamin Kromoser, Wood Material Science & Engineering , online, https://doi.org/10.1080/17480272.2025.2478600. Timber construction has gained significant attention as a sustainable solution to meet the increasing demand driven by population growth. However, climate-induced hazards like forest fires, coupled with the scarcity of high-quality round timber raw materials, pose challenges to the production of traditional engineered wood products. Therefore, strand-based materials like unidirectional strand board (USB) have been developed to address these challenges, by utilizing low-quality wood resources. Shear properties are vital for USB's use in wall and slab elements facing lateral loads. However, the variety of direct and indirect shear methods complicates the determination of reliable results. This study evaluates the shear performance of single-layer USB using modified panel and planar shear tests, with comparisons drawn to oriented strand board (OSB/4). Both modified methods effectively characterized material’s directional variability, with vertical or orthogonal shearing dominating the failure modes. The findings confirmed the orthotropic behavior of USB, with higher shear properties in the processing direction compared to the transversal direction. In addition, USB demonstrated comparable shear performance to OSB/4 in the panel and planar tests in the processing direction. Future research should investigate other mechanical and physical properties, as well as the suitable shear methods for multi-layer USBs to account for mass timber.
Technical Abstracts
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