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Geopolymers based on fly ash are an emerging alternative to ordinary Portland cement, with a low impact on the environment and a potential to increase the sustainability of the concrete-based construction. Reported here is the design and investigation of new wood fiber reinforced geopolymer composites (WFRGC) based on fly ash and wood fiber (5–35 wt%). These WFRGC showed reduced mechanical properties with rising wood fiber addition as calculated by compressive strength with the cylindrical test (7.83–59.82 MPa); compressive strength at cubic test (6.95–50.23 MPa); force load at upper yield (0.70–5.02 KN); flexural strength (1.71–11.05 MPa); compressive modulus at cubic test (0.13–054 GPa); and flexural modulus (3.91–1293.61 MPa). The adding of wood fiber showed decreases of the density WFRGC (1.58–1.87 g/cm3) and decreases the thermal conductivity of WFRGC. The addition 20 wt% wood fiber could be the limit for acceptable mechanical properties. WFRGC with 20–35 wt% wood fibers may be a promising green material for building.

The goal of this study is to find out how some properties of wood–polymer nanocomposites are affected by the processing technology, the nanomaterials, and the ratio of coupling agents. To achieve this objective, the extruded and dry blended samples are made from wood flour with MAPP, ZnO nanoparticles (0, 1, 3, and 5 wt%), and polypropylene. The mechanical properties of the nanocomposites improve significantly with ZnO and MAPP loading. Due to the more homogeneous structure of nanocomposites, better mechanical results are obtained with the extrusion method. With ZnO and MAPP loading, the thermal stability of nanocomposites improves. The storage and loss modulus values indicate that the processing technology of nanocomposites could be a key factor in the resistance of the materials obtained by extrusion. The storage and loss modulus of nanocomposites manufactured by the extrusion technology are determined to be higher than those of the samples produced using the dry blending method.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova-Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH-urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova-Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340-474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

This study was to investigate sepiolite clay nanofibers (SCNs) on some physical, mechanical, and thermal properties of wood-plastic nanocomposites. To meet this objective, pinewood flour with maleic anhydride polypropylene (PP), sepiolite nanofibers (0, 1, 3, 5, and 7 wt%), and PP were compounded in a twin-screw corotating extruder. The mass ratio of the wood flour to PP was 50/50 (wt%/wt%) in all compounds. The test specimens were produced using an injection molding machine from the pellets. Flexural and tensile properties, thickness swelling, water absorption, thermogravimetric analysis, and morphology of the manufactured nanocomposites were evaluated. Based on the findings in this study, flexural and tensile properties of the wood-plastic nanocomposites increased with increasing the content of the sepiolite nanofibers. By increasing the amount of SCNs, thickness swelling and water absorption properties of wood-plastic nanocomposites were improved. Increasing the loading of SCNs increased the amount of residual ash and thermal stability. [ABSTRACT FROM AUTHOR]

Biobased HDPE (bioHDPE) was melt-compounded with different percentages (2.5 to 40.0 wt.%) of short hemp fibers (HF) as a natural reinforcement to obtain environmentally friendly wood plastic composites (WPC). These WPC were melt-compounded using a twin-screw extrusion and shaped into standard samples by injection molding. To improve the poor compatibility between the high non-polar BioHDPE matrix and the highly hydrophilic lignocellulosic fibers, a malleated copolymer, namely, polyethylene-graft-maleic anhydride (PE-g-MA), was used. The addition of short hemp fibers provided a remarkable increase in the stiffness that, in combination with PE-g-MA, led to good mechanical performance. In particular, 40 wt.% HF drastically increased the Young’s modulus and impact strength of BioHDPE, reaching values of 5275 MPa and 3.6 kJ/m2, respectively, which are very interesting values compared to neat bioHDPE of 826 MPa and 2.0 kJ/m2. These results were corroborated by dynamic mechanical thermal analysis (DMTA) results, which revealed a clear increasing tendency on stiffness with increasing the fiber loading over the whole temperature range. The crystal structure was not altered by the introduction of the natural fibers as could be seen in the XRD patterns in which mainly the heights of the main peaks changed, and only small peaks associated with the presence of the fiber appeared. Analysis of the thermal properties of the composites showed that no differences in melting temperature occurred and the non-isothermal crystallization process was satisfactorily described from the combined Avrami and Ozawa model. As for the thermal degradation, the introduction of HF resulted in the polymer degradation taking place at a higher temperature. As for the change in color of the injected samples, it was observed that the increase in fiber generated a clear modification in the final shades of the pieces, reaching colors very similar to dark woods for percentages higher than 20% HF. Finally, the incorporation of an increasing percentage of fibers also increased water absorption due to its lignocellulosic nature in a linear way, which drastically improved the polarity of the composite.

Geopolymers based on fly ash are an emerging alternative to ordinary Portland cement, with a low impact on the environment and a potential to increase the sustainability of the concrete-based construction. Reported here is the design and investigation of new wood fiber reinforced geopolymer composites (WFRGC) based on fly ash and wood fiber (5–35 wt%). These WFRGC showed reduced mechanical properties with rising wood fiber addition as calculated by compressive strength with the cylindrical test (7.83–59.82 MPa); compressive strength at cubic test (6.95–50.23 MPa); force load at upper yield (0.70–5.02 KN); flexural strength (1.71–11.05 MPa); compressive modulus at cubic test (0.13–054 GPa); and flexural modulus (3.91–1293.61 MPa). The adding of wood fiber showed decreases of the density WFRGC (1.58–1.87 g/cm3) and decreases the thermal conductivity of WFRGC. The addition 20 wt% wood fiber could be the limit for acceptable mechanical properties. WFRGC with 20–35 wt% wood fibers may be a promising green material for building. [ABSTRACT FROM AUTHOR]

Biobased HDPE (bioHDPE) was melt-compounded with different percentages (2.5 to 40.0 wt.%) of short hemp fibers (HF) as a natural reinforcement to obtain environmentally friendly wood plastic composites (WPC). These WPC were melt-compounded using a twin-screw extrusion and shaped into standard samples by injection molding. To improve the poor compatibility between the high non-polar BioHDPE matrix and the highly hydrophilic lignocellulosic fibers, a malleated copolymer, namely, polyethylene- graft -maleic anhydride (PE-g-MA), was used. The addition of short hemp fibers provided a remarkable increase in the stiffness that, in combination with PE-g-MA, led to good mechanical performance. In particular, 40 wt.% HF drastically increased the Young's modulus and impact strength of BioHDPE, reaching values of 5275 MPa and 3.6 kJ/m 2 , respectively, which are very interesting values compared to neat bioHDPE of 826 MPa and 2.0 kJ/m 2 . These results were corroborated by dynamic mechanical thermal analysis (DMTA) results, which revealed a clear increasing tendency on stiffness with increasing the fiber loading over the whole temperature range. The crystal structure was not altered by the introduction of the natural fibers as could be seen in the XRD patterns in which mainly the heights of the main peaks changed, and only small peaks associated with the presence of the fiber appeared. Analysis of the thermal properties of the composites showed that no differences in melting temperature occurred and the non-isothermal crystallization process was satisfactorily described from the combined Avrami and Ozawa model. As for the thermal degradation, the introduction of HF resulted in the polymer degradation taking place at a higher temperature. As for the change in color of the injected samples, it was observed that the increase in fiber generated a clear modification in the final shades of the pieces, reaching colors very similar to dark woods for percentages higher than 20% HF. Finally, the incorporation of an increasing percentage of fibers also increased water absorption due to its lignocellulosic nature in a linear way, which drastically improved the polarity of the composite.

The problem of using natural building materials in low-rise construction lies in ensuring their durability during operation in conditions of atmospheric fluctuations, as well as in ensuring their thermal insulation properties. The purpose of this study is to find the thermal insulation properties of materials, namely thermally modified common hornbeam wood (the outer surface of the building), common pine wood (the inner surface of the building) and a thermal insulation layer of reeds, which allow justifying the effectiveness of their use in construction. The study uses a comprehensive research method, which included figuring out the thermal insulation properties of materials and justifying their feasibility in construction. The thermal insulation properties of wood and reed materials were calculated based on thermophysical dependences. The coefficient of thermal conductivity for wood reaches 0.0082 W/(m∙K), and for reed – 0.0022 W/(m∙K). Therewith, the thermal conductivity is no more than 0.19·10-6 m²/s, the heat capacity of wood is within 70÷90 kJ/(kg·K), and the heat capacity of a reed product is 337.2 kJ/(kg·K) respectively, which refers them to thermal-insulating materials. The practical value of this study lies in the substantiation of the method of establishing thermal insulation characteristics of building materials by finding their physical and thermophysical properties. The obtained results also expand the scope of application of products and building structures made of wood and reed. [ABSTRACT FROM AUTHOR]

Biobased HDPE (bioHDPE) was melt-compounded with different percentages (2.5 to 40.0 wt.%) of short hemp fibers (HF) as a natural reinforcement to obtain environmentally friendly wood plastic composites (WPC). These WPC were melt-compounded using a twin-screw extrusion and shaped into standard samples by injection molding. To improve the poor compatibility between the high non-polar BioHDPE matrix and the highly hydrophilic lignocellulosic fibers, a malleated copolymer, namely, polyethylene-graft-maleic anhydride (PE-g-MA), was used. The addition of short hemp fibers provided a remarkable increase in the stiffness that, in combination with PE-g-MA, led to good mechanical performance. In particular, 40 wt.% HF drastically increased the Young's modulus and impact strength of BioHDPE, reaching values of 5275 MPa and 3.6 kJ/m2, respectively, which are very interesting values compared to neat bioHDPE of 826 MPa and 2.0 kJ/m2. These results were corroborated by dynamic mechanical thermal analysis (DMTA) results, which revealed a clear increasing tendency on stiffness with increasing the fiber loading over the whole temperature range. The crystal structure was not altered by the introduction of the natural fibers as could be seen in the XRD patterns in which mainly the heights of the main peaks changed, and only small peaks associated with the presence of the fiber appeared. Analysis of the thermal properties of the composites showed that no differences in melting temperature occurred and the non-isothermal crystallization process was satisfactorily described from the combined Avrami and Ozawa model. As for the thermal degradation, the introduction of HF resulted in the polymer degradation taking place at a higher temperature. As for the change in color of the injected samples, it was observed that the increase in fiber generated a clear modification in the final shades of the pieces, reaching colors very similar to dark woods for percentages higher than 20% HF. Finally, the incorporation of an increasing percentage of fibers also increased water absorption due to its lignocellulosic nature in a linear way, which drastically improved the polarity of the composite. [ABSTRACT FROM AUTHOR]

Due to its relatively lower thermal conductivity, the suitability of wood is called into question when selecting the flooring material best suited to radiant heating systems. The European standard EN 1264 considers floorings with a thermal resistance over 0.15 m2 K/W to be out of scope. This belief was partially disproved in a previous article that studied wooden floors for Madrid’s climate. However, the effect of climate still needs to be addressed. The present study extends the previous research to worldwide climates and aimed to answer the following questions: (1) Do the lowest thermal conductivity woods present good thermal performance when used in radiant floors? (2) Should the flooring have a maximum thermal resistance value? (3) Is the standard thermal resistance limit of 0.15 m2 K/W objectively justified? And (4) Do the answers of the preceding questions depend on the climate and the construction characteristics? To answer these questions, 28 cities were selected according to the Köppen–Geiger climate classification. In each city, 216 different dwellings were simulated with 60 wood floorings and one of low thermal resistance as a reference, comprising a total of 368,928 cases. Thermal performance was evaluated in terms of three parameters: energy demand, thermal comfort, and start-up lag time. Consequently, the answers to the previous questions were: (1) The lowest thermal conductivity woods can be used efficiently worldwide in radiant floor heating systems with start-up lag times close to that of the reference flooring; (2) There is no limit value for thermal resistance for floorings that can be applied to all dwellings and climates; (3) No objective justification was found for establishing a thermal resistance limit for flooring of 0.15 m2 K/W; and (4) Climate and construction characteristics can play an important role in the correct selection of flooring properties, especially in severe winters and dwellings with the greatest outdoor-exposed envelope and the worst insulation.

The article focuses on the study of the thermal properties of pine wood, a material traditionally used in construction, especially in Poland. The trend towards sustainable construction necessitates a deeper analysis of its properties. Due to the insufficient amount of data in the literature on the thermal conductivity of pine wood, detailed studies were conducted, taking into account different wood densities. Seasoned wood samples were subjected to various processes and tests, measuring the heat conduction coefficient under different conditions. These results are relevant in the context of sustainable construction and will assist in further research on wood as a building material. The studies also took into account the effects of temperature and humidity on the thermal properties of wood, which are crucial for its application in various environmental conditions. [ABSTRACT FROM AUTHOR]

In civil construction, one of the primary challenges associated with wood application is its high flammability and low durability during fires. Although chemical treatment with fire-retardant properties exists, they are expensive and of non-renewable origin. Tannin, a wood extractive, being a phenolic compound, holds promise for enhancing the thermal properties of wood. This study aimed to assess the efficacy of tannin as a fire retardant and compare it with a commercial product, as well as comparing different application techniques for these products. Wood samples from the Simarouba amara Aubl. species were utilized. Tannin and a commercial flame retardant were applied via immersion, vacuum impregnation, brushing, and a treatment of tannin incorporated into water-based wood varnish. Alongside the burning test performance, assessments of the wood's physical properties, such as colorimetry, thermal stability, and mass retention, were conducted. The application of tannin altered the wood's color and reduced the spread of fire; its presence significantly reduced the flame duration and maintained the wood's structural integrity. However, tannin retention was lower compared to commercial flame retardant, leading to reduced fire retardancy. Among the methods tested, immersion proved to be the most effective in enhancing the wood's resistance to flame contact. [ABSTRACT FROM AUTHOR]

Heat storage technology（TES） can effectively improve the thermal performance of building materials. Phase change materials used for TES have high heat storage and good biocompatibility, but low thermal conductivity and low heat transfer efficiency. By TES technology, new wood-derived composites with different SAED content were prepared with delignin wood（DW） as the carrier, polyethylene glycol（PEG） as the heat storage material, and SrO·Al2O3:Eu2+,Dy3+（SAED） as the thermal conductivity material. Meanwhile, the influence of SAED content on the thermal properties of wood-derived composites was investigated. Combined with the actual process, the heat transfer model of the heat storage process is established and solved. The results show that the thermal conductivity and heating rate of 40%SAED/PEG/DW are 57.14% and 29.76% higher than that of pure PEG/DW, respectively. The model was used to solve the pure PEG/DW, 20%, 30% and 40% SAED/PEG/DW heat storage process, and the standard error SE was 1.35 ℃, 1.92 ℃, 1.73 ℃ and 1.35 ℃ respectively by comparing the actual value and the simulated predicted value. The prediction errors PE are 2.82%,-0.41%,-0.19% and-0.55%, respectively. The simulation results are in good agreement with the measured results, which can effectively predict the temperature change of the heat storage process and guide the actual production. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the parameters controlling auto-ignition, degradation and auto-extinction of wood. For this purpose an extensive set of experiments was conducted varying extrinsic parameters such as external heat-flux but also the type of wood. Varying the wood species allowed to explore the role of thermal properties and wood composition. Seven wood samples were tested, some light and some heavy, both hardwood and softwood. The experimental setup was based on a double-cone calorimeter, which allowed to accurately change the imposed heat flux at a predefined moment. More than 600 tests were carried out in a vertical orientation, allowing a statistical analysis. For each test, mass loss, surface temperature and in-depth temperature of the samples were measured using a precision scale, an infrared camera and thin wire thermocouples embedded using a special machining, respectively. The auto-ignition study showed that the time to auto-ignition increases linearly with density. Despite a wide range of these times to ignition, the surface temperatures at ignition were in the same order of magnitude for all species considered: between 450 and 700 °C for auto-ignition before 2 min and between 700 and 800 °C for auto-ignition after 2 min. The onset of char oxidation was observed at low heat fluxes. It occurs at different times depending on the wood species, but at similar surface temperatures, between 380 and 400 °C. The sliding double heating cone made it possible to identify the criteria for auto-extinction: the heat flux for auto-extinction can vary from 40 to 55 kW.m−2 depending on the wood species, and a linear correlation was found between the mass loss rate at extinction and the initial density of each sample studied. The study highlights the dominant role of density for auto-ignition and auto-extinction. • Study of fire behavior in vertical orientation by 600 tests at the cone calorimeter scale. • Comparison of piloted and spontaneous ignition as well as surface temperature at ignition of 7 wood species through more than 150 tests. • Study of the degradation of seven species of wood by measuring the surface temperature, in-depth temperatures and mass loss rate for five heat fluxes. • Study of flame extinction conditions for the seven wood species (critical heat flux and critical mass loss rate). [ABSTRACT FROM AUTHOR]

Polymer composites especially bio composites can be manufactured using different combination of matrix and fiber-reinforcement materials and produces different properties for different combinations. But with the usage of natural fibers and certain matrix materials, it leads to moisture absorption in these materials which causes deterioration of bonding between matrix and fiber. This can lead to reduction in tensile properties, flexural properties, and impact properties of the composite. This problem can be overcome by using chemical-treated fiber, coating fiber, or composite with suitable materials, addition of certain fillers in the composite, or by hybridizing the fibers used as reinforcement in the composite. In this present study, various factors affecting moisture absorption by a composite, its effect on the properties of the composite, different liquids which can get absorbed by the composite, models used to study moisture absorption, and methods to reduce moisture absorption in the composite are discussed. [ABSTRACT FROM AUTHOR]

Plant-based hemp natural fibre-reinforced composites are sustainable in the view of the environment. However, these composites have not attracted many applications due to their less mechanical properties compared to the synthetic fibre-reinforced composites. The present work reports the hemp fibre-reinforced composite loaded with cellulose-based filler to improve their mechanical properties. At equal proportions of cellulose filler such as pistachio shell powder, teak wood powder, groundnut shell powder reinforced with the hemp fibre-reinforced epoxy composite, the improvement in the tensile strength, flexural strength, % of elongation and % of deformation is reported. The hemp fibre/epoxy composite loaded with 5 wt% of pistachio shell powder shows a 9.28% increment in tensile strength, 50.96 % increment in flexural strength compared to hemp fibre/epoxy composite. The hemp/epoxy composite loaded with 5 wt% teak wood powder particles shows enhancement in tensile, flexural by 31.56 %, 35.97%, respectively. The hemp/epoxy composite loaded with 5 wt% groundnut shell powder particles shows enhancement in tensile, flexural by 42.99 %, 83.99%, respectively. [ABSTRACT FROM AUTHOR]

This study was focused on developing and evaluating the impacts of wood and graphite fillers on an E-glass fibre-reinforced polyester composite. The fillers employed in this study include teak, casuarina, psuedon wood dust, graphite, and hybrid fillers such as casuarina and graphite fillers. They tested for tension, flexural, impact, hardness, and dynamic mechanical analysis. In the current work, the optimum loading level is 15 wt% which was determined through testing at various loading levels. The experimental results have shown that the mechanical, physical, and thermomechanical properties of glass fiber reinforced polyester composites improvement mechanism analysis depend upon chemically treated wood dust fillers by avoiding surface delamination during fabrication. By using the hand layup method, composites were created by maintaining the fibre constant while distributing the fillers following the rule of mixture; a hybrid composite has a filler distribution of 1:1. Hybrid composite has exhibited increased flexural strength and hardness by 72.77%, 63.33% compared to casuarina wood of 15 wt% by avoiding incompatibility of casuarina wood filler with the resin. The glass transition value of the hybrid composite was increased by 1.4% compared to the above said casuarina wood composite, making it a more thermally resistant material. The hardness of the hybrid composite has increased by 2.78% compared to the teak wood of 15 wt% composite. [ABSTRACT FROM AUTHOR]

Buildings consume significant energy, much of which is used for heating and cooling. Insulation reduces undesired heat transfer to save on heating and cooling energy usage. Radiant barriers are a type of insulation technology that reduces radiant heat absorbed by a structure. Applying radiant barriers to buildings reduces costs and improves both energy efficiency and occupant comfort. However, homes often have favorable thermal gradients that could also be used to reduce energy usage if the insulation properties were switched dynamically. This article introduces two dynamic radiant barriers intended for residential attics, which can switch between reflecting and transmitting states as needed. These radiant barriers are manufactured as a single deformable assembly using sheet materials and are compatible with various actuation mechanisms. The efficacy of these radiant barriers is reported based on a hotbox experiment and numerical calculations. The experimental results demonstrate that both proposed dynamic radiant barrier designs increase effective thermal resistance by factors of approximately 2 when comparing insulating to conducting states, and by approximately 4 when comparing the insulating state to the case without a radiant barrier. Additionally, the dynamic radiant barriers achieve heat flux reductions up to 41.9% in the insulating state compared to tests without a dynamic radiant barrier. [ABSTRACT FROM AUTHOR]

A significant waste material threatening sustainability efforts are post-consumer food packaging goods. These ubiquitous multi-materials comprise chemically disparate components and are thus challenging targets for recycling. Herein, we undertake a proof-of-principle study in which we use a single-stage method to convert post-consumer multi-material food packaging (post-consumer peanut butter jars) to a high compressive strength composite (PBJS90). This is accomplished by thiocracking the ground jar pulp (10 wt. %) with elemental sulfur (90 wt. %) at 320 °C for 2 h. This is the first application of thiocracking to such mixed-material post-consumer goods. Composite synthesis proceeded with 100% atom economy, a low E factor of 0.02, and negative global warming potential of −0.099 kg CO2e/kg. Furthermore, the compressive strength of PBJS90 (37.7 MPa) is over twice that required for Portland cement building foundations. The simplicity of composite synthesis using a lower temperature/shorter heating time than needed for mineral cements, and exclusive use of waste materials as precursors are ecologically beneficial and represent an important proof-of-principle approach to using thiocracking as a strategy for upcycling multi-materials to useful composites. [ABSTRACT FROM AUTHOR]

Lightweight engineered trusses support sustainable construction with the benefits of mass production and fast construction at lower costs. However, the truss system has raised concerns due to premature failure in fire conditions. This study investigates the effect of a thin soot layer on the surface of the gusset plate and the teeth of the gusset plate on the temperature development within lightweight wood specimens in fire conditions. A 10 cm long, 8.9 cm wide, and 3.8 cm thick dimensional lumber (often called 2 by 4) partially covered by a gusset plate was exposed to a constant incident radiant heat flux. A total of 12 experiments were conducted with four different configurations, bare gusset plates with and without teeth and soot-coated gusset plates with and without teeth, at three different external radiative heat fluxes of 10, 15, and 20 kW/m2. The exposure durations were set to be 60, 40, and 30 min, respectively, to allow the total applied amount of radiant energy for each specimen to be identical. Three thermocouples were installed at a depth of 13 mm from the exposed wooden surface: two beneath the gusset plate and one below the uncovered wooden surface, and an additional thermocouple was between the gusset plate and the wood surface. The obtained temperature data showed that soot-coated gusset plates absorb significantly more radiation and record higher temperatures within the specimens than the specimens with the bare gusset plates. It was also found that the bare gusset plate works as a protective layer for the wood at 20 kW/m2, but not at 10 and 15 kW/m2. The teeth certainly contributed to heat transfer increasing the temperatures within the wood higher than those without teeth, but the effect was only meaningful for the soot-covered specimens. Connection strength was also qualitatively analyzed and it was discovered that the bare specimen retained a strong connection between the gusset plate and wood. In contrast, the soot-coated specimen was easily removed by hand, even when exposed to the same heat flux. Applying these results to a realistic scenario, this loss in connection strength could result in truss failure and structural collapse, which may result in injury to or even death of the responding firefighters. Additional gusset plate protection measures may be necessary to prolong the connection strength and prevent structural collapse. [ABSTRACT FROM AUTHOR]

This study aims to investigate the potential of integrating natural biochar (BC) derived from eggshell waste into flexible polyurethane (FPU) foam to enhance its mechanical and acoustic performance. The study explores the impact of incorporating BC at various weight ratios (0.1, 0.3, 0.5, and 0.7 wt. %) on the properties of the FPU foam. Additionally, the effects of modifying the BC with (3-aminopropyl)trimethoxysilane (APTMS) at different ratios (10, 20, and 30 wt. %) and the influence of diverse particle sizes of BC on the thermal, mechanical, and acoustic characteristics of the FPU composite are investigated. The functional groups, morphology, and elemental composition of the developed FPU composites are analyzed using Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) techniques. Characteristics such as density, gel fraction, and porosity were also assessed. The results reveal that the density of FPU foam increased by 4.32% and 7.83% while the porosity decreased to 50.22% and 47.05% with the addition of 0.1 wt. % of unmodified BC and modified BC with 20 wt. % APTMS, respectively, compared to unfilled FPU. Additionally, the gel fraction of the FPU matrix increases by 1.91% and 3.55% with the inclusion of 0.1 wt. % unmodified BC and modified BC with 20 wt. % APTMS, respectively. Furthermore, TGA analysis revealed that all FPU composites demonstrate improved thermal stability compared to unfilled FPU, reaching a peak value of 312.17°C for the FPU sample incorporating BC modified with 20 wt. % APTMS. Compression strength increased with 0.1 wt. % untreated BC but decreased at higher concentrations. Modifying BC with 20% APTMS resulted in an 8.23% increase in compressive strength compared to unfilled FPU. Acoustic analysis showed that the addition of BC improved absorption, and modified BC enhanced absorption characteristics of FPU, reaching Class D with a 20 mm thickness. BC modified with APTMS further improved acoustic properties compared to the unfilled FPU sample (Class E), with 20% modification showing the best results. These composites present promising materials for sound absorption applications and address environmental issues related to eggshell waste. [ABSTRACT FROM AUTHOR]

Wood sandwich panels are widely utilized in residential, commercial, and industrial settings due to their excellent thermal insulation characteristics, ease of installation, and high strength-to-weight ratio. This review provides an overview on experimental outcomes demonstrating the structural integrity and versatility of wood sandwich panels. It highlights recent advancements in meeting payload requirements and their effectiveness in reducing costs and weights for prefabricated houses. The review focuses on structural applications and material efficiency, showcasing their roles in lightweight, durable constructions for retrofitting and new projects. The potential of novel, sustainable materials in construction is explored, addressing current challenges and emphasizing the diverse applications and environmental benefits of wood-based sandwich panels, underscoring their importance in advancing energy-efficient and sustainable construction. [ABSTRACT FROM AUTHOR]

The main aim of the present work is to evaluate and characterize the mechanical, morphological and thermal properties of wastes coming from the textile industry, mainly composed of cotton and polyester. These wastes will be thereafter implemented in commodity plastic such as polyamide, in order to develop new formulations of environmentally friendly materials. The composites were produced by extrusion and injection-molded processes in amounts between 15 wt.% and 60 wt.% of textile waste. With the objective of improving the properties of the materials, silanes were used as a compatibilizer between the textile fibers and the polymeric matrix. The effect of the compatibilizer in the composites was studied together with the effect of the amount of textile fiber added to the composites. Mechanical, thermal, morphological and wettability properties were analyzed for each composite. The results show that the use of silanes improves the interaction especially in those composites with a higher amount of textile waste, offering a balanced mechanical behavior with significantly high quantities. On the other hand, the melting temperature does not vary significantly with the introduction of silanes and textile waste content, although the incorporation of textile waste slightly reduces up to 23% the degradation temperature of the resulting composites. The wettability of the composites is also increased up to 16% with the incorporation of textile waste. Finally, the appearance of the composites with textile waste is strongly influenced by the incorporation of the reinforcement, offering shades close to dark brown in the whole range of compositions. [ABSTRACT FROM AUTHOR]

The increasing global commitment to carbon neutrality has propelled a heightened focus on sustainable construction materials, with wood emerging as pivotal due to its environmental benefits. This review explores the development and application of eco-friendly polymer nanocomposite coatings to enhance wood's fire resistance, addressing a critical limitation in its widespread adoption. These nanocomposites demonstrate improved thermal stability and char formation properties by integrating nanoparticles, such as nano-clays, graphene oxide, and metal oxides, into biopolymer matrices. This significantly mitigates the flammability of wood substrates, creating a robust barrier against heat and oxygen. The review provides a comprehensive examination of these advanced coatings' synthesis, characterization, and performance. By emphasizing recent innovations and outlining future research directions, this review underscores the potential of eco-friendly polymer nanocomposite coatings as next-generation fire retardants. This advancement supports the expanded utilization of wood in sustainable construction practices and aligns with global initiatives toward achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

This article presents the results of research on the development of chemically resistant polymer–mineral casting composites based on industrial waste. The aim of this work is to develop a technological basis for obtaining effective inorganic fillers and highly filled composites for use in chlorine-containing environments. On the basis of theoretical data, mineral fillers and a polymer binder for filling composites were selected, optimal quantities of input hardeners and an appropriate thermal curing mode were determined, and the influence of the filling degree on the properties of composites was studied. The influence of various factors on the properties of the obtained composites was also studied, and the possibility of using local raw materials to obtain special-purpose composites was investigated. Ash from a thermal power plant (TPP) was used as an acid-resistant filler in composites. Two components were chosen as binders: phenol formaldehyde resin and mineral filler (TPP ash). As the third component, hydrolytically active fillers—anhydrite, phosphogypsum and phosphate slag—were used. The degree of filling has a significant influence on the properties of composites, including the compressive strength, chemical resistance and degree of curing, the values of which were elucidated across a wide range of composite variations based on the degree of filling. The conducted research allowed us to establish the limit of admissible anhydrite content, which should not exceed 15 mas.%. To optimize the chemical resistance and durability of the composites of the investigated substances, the method of mathematical planning was used. According to the results of this study, the optimal compositions of composites, in terms of anhydrite, phosphogypsum and phosphorus slag contents, were selected. At the maximum possible degree of filling, these composites exhibit high target characteristics. [ABSTRACT FROM AUTHOR]

All-cellulose composites (ACCs) have been fabricated by using a variety of cellulosic sources, versatile technologies, and are sustainable alternatives for traditional composites. In this study, nonwoven-woven ACC laminates were created from wood-based Spinnova short fibers and Lyocell fabrics via partial dissolution and an NaOH-urea solvent system. The less-known wood-based Spinnova fiber is created for the textile industry, but it also has great potential for the composite industry. To identify the mechanical properties of ACCs--which greatly influence the range of material application--tensile, impact, and flexural tests were conducted. The mechanical properties indicated only moderate properties, which are influenced by high porosity and weak fiber bonding. Despite this, valuable information on the nonwoven-woven structured ACCs was obtained. To improve the ACC laminate's ability to resist moisture, biobased coatings (e.g., commercially available birch bark betulin and suberin acid mixture) were applied on the surface of ACCs and it successfully improved the wetting resistance. The results of contact angle analyses demonstrated that the highest contact angle of 128° was measured for betulin-coated laminates and the best stable hydrophobicity calculated a minute after the beginning of the experiment were observed at 109° for the uncommercial pressurized hot ethanol (PHE) extract of birch bark. [ABSTRACT FROM AUTHOR]

This study involved the optimization of the molded pieces manufacturing process from a poly-3-hydroxybutyrate-co-3-hydroxyvalerate biocomposite containing 30% wood flour by mass. The amount of wood flour and preliminary processing parameters were determined on the basis of preliminary tests. The aim of the optimization was to find the configuration of important parameters of the injection process to obtain molded pieces of good quality, in terms of aesthetics, dimensions, and mechanical properties. The products tested for quality were dog bone specimens. The biocomposite was produced using a single-screw extruder, whereas molded pieces were made using an injection molding process. The Taguchi method was applied to optimize the injection molding parameters, which determine the products quality. Control factors were selected at three levels. The L27 orthogonal plan was used. For each set of input parameters from this plan, four processing tests were performed. The sample weight, shrinkage, elongation at break, tensile strength, and Young's modulus were selected to assess the quality of the molded parts. As a result of the research, the processing parameters of the tested biocomposite were determined, enabling the production of good-quality molded pieces. No common parameter configuration was found for different optimization criteria. Further research should focus on finding a different range of technological parameters. At the same time, it was found that the range of processing parameters of the produced biocomposite, especially processing temperature, made it possible to use it in the Wood Polymer Composites segment. [ABSTRACT FROM AUTHOR]