To address the flammability of bamboo decorative filament, seven waterborne composite flame-retardant coating systems were developed using waterborne acrylic resin as the film-forming matrix, with boric acid, borax, ammonium polyphosphate (APP), nano-SiO2, and disodium octaborate tetrahydrate (DOT). The filament was treated as primer-only, topcoat-only, and combined primer/topcoat application. The combustion performance was evaluated by a cone calorimeter following ISO 5660-1: 2002. The results indicated that in the primer-only coating system, the boric acid/borax/disodium octaborate tetrahydrate composite system reduced total smoke production (TSP) by 11.90%, while the total heat release (THR) of the boric acid/borax/disodium octaborate tetrahydrate/ammonium polyphosphate composite system decreased by 18.83%. In the topcoat-only system, the boric acid/borax single-component system exhibited the optimal comprehensive performance, which the peak value of heat release rate (HRR) and the TSP decreased 13.54% and 8.24%, resp. In the combined primer-topcoat systems, THR reductions of 10.99% and 10.21% were achieved. Notably, nano-SiO2/boric acid/borax exhibited superior smoke suppression performance, with a 14.12% decrease in TSP, attributed to the synergistic physical barrier effect between the silicate network formed by nano-SiO2 and the boron-based glassy protective layer.
This study proposes a novel approach involving steam explosion for the production of fibrillated cellulose using distillery refuse as a by-product of bioethanol production. The effect of the steam explosion with or without additional pre-treatment or post-treatment of distillery refuse on lignin and hemicellulose degradation was studied by infrared spectroscopy and fibre length distribution. Partial decomposition of hemicellulose was observed after the use of steam explosion combined with acid-alkali pre-treatment. The process was less effective by using steam explosion, followed by oxidation and bleaching, however, it showed better results in comparison with steam explosion followed by single oxidation. Steam explosion combined with acid-alkali pre-treatment or with oxidation combined with bleaching effectively decomposed lignin. Average arithmetic fibre length after treatment by single steam explosion rapidly decreased but additional treatments no longer caused its further decline. The application of fibrillated cellulose obtained by a single steam explosion on the filter decreased the average pore size. Anchoring of metal salts combined with fibrillated fibres on paper surface was confirmed by SEM-EDS and its ability to act as a barrier against microorganisms was proved.
This study evaluated the ACQ treatability of 24 local timber species through vacuum pressure impregnation and correlated preservative retention and penetration with physical and anatomical wood properties. Retention ranged widely from 0.478 kg m⁻³ (Bridelia retusa) to 14.980 kg m⁻³ (Cullenia ceylonica and Cupressus macrocarpa). Based on retention and Chrome Azurol S (CAS) penetration assessment, species were classified into four treatability classes. One-way ANOVA confirmed highly significant differences in density (F₂₃,₄₈=199.79; p<0.001), moisture content (F₂₃,₄₈=48.04; p<0.001), and ACQ retention (F₂₃,₄₈=82.75; p<0.001) across species. Pearson correlation analysis revealed a very strong positive relationship between fibre wall thickness and wood density (r=0.955; p<0.05) and a strong negative relationship between fibre lumen diameter and density (r= −0.903; p=0.001), demonstrating that fibre morphology is the dominant determinant of wood density. Neither density (r= −0.411; p=0.163), moisture content (r = 0.005; p = 0.987), total ray area (r=0.097; p=0.789), total vessel area (r= −0.021; p=0.932), fibre wall thickness (r=0.082; p=0.725), nor fibre lumen diameter (r=0.302; p=0.183) produced statistically significant correlations with ACQ retention, indicating that preservative uptake is governed by the combined interactive influence of multiple anatomical and chemical wood properties rather than any single parameter. Cullenia ceylonica, Cupressus macrocarpa, and Ficus amplissima were identified as the most effectively treatable species, classified as very easy to treat (Class 4, retention >10 kg m⁻³) with full penetration exceeding 25 mm. These findings provide a species-specific treatability database for Sri Lankan timber and highlight the need for multi-variable modelling in future preservative research.
This article deals with the influence of gypsum board cladding and mechanical fastening on the thermal degradation of a timber substrate exposed to external radiant heat flux. Test specimens consisting of spruce wood protected by either standard gypsum board or fire-rated gypsum board were exposed to a heat flux of 50 kW & centerdot;m-2 in a cone calorimeter. Temperature development was monitored using thermocouples placed at the gypsum board-wood interface and inside the timber element within a pre-drilled hole with a diameter of 1 mm. In addition, thermogravimetric analysis of the individual components of the tested assembly was performed. The results indicate that the dehydration of gypsum significantly slows down heat transfer to the timber substrate. Samples protected by fire-rated gypsum board showed a slower temperature increase, lower CO production, and a greater residual thickness of timber compared to samples with standard gypsum board. No significant effect of the screw on temperature development or residual timber thickness was observed.
In this study, wood-plastic composites were prepared using waste wood powder (WWP) and polybutylene succinate (PBS). Three interfacial modifiers, gamma-glycidoxypropyltrimethoxysilane (KH560), isopropyl tri(dioctylpyrophosphate) titanate (CS201), and maleic anhydride-grafted PBS (MAPBS) were used to modify the interface of the composites and enhance the mechanical properties. The materials were characterized using infrared spectroscopy, three-point bending, and water absorption tests. The results indicated that all three interfacial modifiers were successfully grafted onto the wood powder surface, thereby influencing the mechanical properties. When the mechanical properties of the composites reached their optimal levels, the optimal loading levels of KH560, CS201, and MAPBS were 2%, 1%, and 2%, resp. At this point, compared to the unmodified composite, the elastic modulus increased by 9.44%, 15.03%, and 12.92%, resp; the flexural strength increased by 5.35%, 11.51%, and 8.91%, resp; the water absorption decreased by 4.88%, 3.68%, and 6.21%, resp; and the thickness swelling decreased by 4.56%, 3.08%, and 7.54%, resp.
