Abstract: Acid hydrolysis can be more efficient than water hydrolysis, particularly in breaking down cured adhesives found in waste panels within a shorter reaction time that could benefit large-scale industrial processes. This study evaluates the effects of various acid hydrolysis conditions on the thermal, physical, and chemical properties of recycled particles intended for particleboard production. Particleboards were recycled using oxalic acid and ammonium chloride at different concentrations and reaction times at 122 °C. The thermal stability of the particles was determined by thermogravimetric analysis. Particle size distribution, particle morphology, nitrogen content, pH and acid/base buffer capacity were analyzed. The effect of the recycled particles on the urea-formaldehyde (UF) curing was assessed using differential scanning calorimetry and the gel time method. The recycled particles exhibited a higher thermal degradation beyond 200 °C, indicating their thermal stability for manufacturing new panels. The acid treatments did not damage the anatomical structure of the particles. The nitrogen content of recycled particles decreased by up to 90% when oxalic acid was used, compared to raw board particles. Recycled particles had a lower pH, a lower acid buffer capacity, and a higher base buffer capacity than those of raw board particles. The recycled particles did not significantly affect the peak polymerization temperature of the UF adhesive. However, some treatments affected the gel time of the adhesive. The results indicate that particleboards can be effectively recycled through acid hydrolysis, mainly with oxalic acid, which gives better results than hydrolysis using water alone. Oxalic acid showed increased selectivity in eliminating the cured UF adhesive, resulting in recycled particles suitable for manufacturing new panels.

Abstract: This study aimed to develop a mathematical model describing the thermal dissipation kinetics during the post-processing cooling phase of flat-pressed wood–polymer composites (FPWPC). The model elucidates the relationship between the composite's cooling time and the spatiotemporal temperature distribution across its thickness, as influenced by wood particle content, initial surface temperature, and bulk density. Analysis of the thermal profile in the core layer revealed three distinct phases: an initial temperature increase, a thermal peak, and a convective cooling phase. The results demonstrate that both the wood particle content and the initial surface temperature significantly affect the thermal dissipation rate. Higher initial surface temperatures (e.g., 200 °C) led to an initially accelerated cooling rate, followed by a deceleration phase. Composites with higher wood particle content (60%) exhibited slower cooling rates, which is attributed to the lower thermal conductivity of wood relative to the thermoplastic polymer matrix, resulting in greater thermal retention. Bulk density was also found to play a critical role in thermal management by influencing the composite’s specific heat capacity, thermal conductivity, and convective heat transfer efficiency. The proposed mathematical model offers potential for optimizing FPWPC manufacturing processes by enabling more precise control over cooling dynamics.

Abstract: The pine cone is an important forest product for the Portuguese economy. However, it is associated with environmental impacts, such as the generation of waste and the increased risk of forest fires. The objective of this research is to valorise waste from the production of Pinus pinaster Aiton in the form of natural dyes. The pine cone extracts were characterised in different alkaline solutions (1%, 5% and 10% NaOH) in order to evaluate the dyeing process on cotton knitwear, using the CIELab coordinates. The dyed samples were also subjected to light and water fastness tests. The extracts showed an increase in solids content with increasing alkalinity and a reduction in antioxidant content. The phenol content increased in the extract with 5% but decreased with the 10% concentration. All the dyes expressed a pink colour, but with different shades. About the L* coordinate (luminosity), the colours became lighter as the NaOH increased. n the a* coordinate, all the samples had a reddish colour and, in the b* coordinate, all the samples had a yellowish colour. About light and water fastness, all the samples lost colour, but in the water test it was not noticeable.

Abstract: This paper discusses how to make a diaper made with biodegradable materials. With the population increasing, pollution has become more prevalent in our current society, especially with waste that cannot be broken down and composted. Other companies that make diapers do not make use of environmentally friendly materials. Instead, they use gels and cloths that are not able to decompose. We used kapok fiber and bamboo cloth to tackle this problem and create environmentally safe and fully biodegradable diapers. We tested the diaper prototype dubbed the “Kaboo Diaper” using the rewet and absorbency test. The absorbency test showed that the diaper absorbed 323g of simulated urine. The rewet test showed that the diaper picked up 24g of water over time, passing industry standards. Showing the diapers to mothers contacted by the Health and Sanitation unit of Brgy. Oranbo deemed the prototype ready to use.

Abstract: The use of veneer composites as structural components in engineering requires special design. The dimensioning of laminated wood can be optimized by varying the wood species, veneer thickness, orientation, arrangement, number of single layers, and other factors. Composite properties can be calculated by suitable model approaches, such as the classical laminate theory. Thus, an optimization can be achieved. The present study verifies the adaptability of the classical laminate theory for veneer composites. Native veneer, adhesive-coated veneer, and solid wood were investigated as raw materials for the plywood layers. Mechanical properties were determined by tensile and shear tests and used as parameters to calculate the composite properties of the plywood. The plywood was bending tested, and the values obtained were compared with the calculations. The best prediction of the plywood properties is obtained by using the properties of the adhesive coated veneer as a single layer.

Abstract:

With portable electronics and new-energy vehicles booming, the demand for high-performance energy storage devices has skyrocketed. Supercapacitor separators are thus vital. Traditional ones such as polyolefins and non-woven fabrics have limitations, while cellulose and its derivatives, with low cost, good hydrophilicity, and strong chemical stability, are potential alternatives. This study used regenerated cellulose Lyocell fibers. Through fiber treatment, refining, and in situ deposition, a composite regenerated cellulose separator (NFRC-Ba) with nano-barium sulfate was made. Its physical, ionic, and charge–discharge properties were tested. The results show that NFRC-Ba excels in terms of mechanical strength, porosity, hydrophilicity, and thermal stability. Compared with the commercial NKK30AC-100 separator, it has better ionic conductivity, better ion-transport ability, a higher specific capacitance, better capacitance retention, and good cycle durability. It also performs stably from -40°C to 100°C. With a simple and low-cost preparation process, NFRC-Ba could be a commercial separator for advanced supercapacitors.

Abstract:

Inferring forest properties is crucial for the timber industry, enabling efficient monitoring, predictive analysis, and optimized management. Nondestructive testing (NDT) methods have proven to be valuable tools for achieving these goals. Recent advancements in data analysis, driven by machine learning (ML) algorithms, have revolutionized this field. This study analyzed 492 eucalyptus trees, aged 3 to 7 years, planted in São Paulo, Brazil. Data from forest inventories were combined with results from ultrasound, drilling resistance, sclerometric impact, and penetration resistance tests. Seven machine learning algorithms were evaluated to compare their generalization capabilities with conventional statistical methods for predicting basic wood density. Among the models, Extreme Gradient Boosting (XGBoost) achieved the highest accuracy, with a coefficient of determination (R²) of 89% and a root mean square error (RMSE) of 10.6 kg·m⁻³. In contrast, the conventional statistical model, using the same parameters, yielded an R² of 33% and an RMSE of 26.4 kg·m⁻³. These findings highlight the superior performance of machine learning in nondestructive inference of wood properties, paving the way for its broader application in forest management and the timber industry.

Abstract:

Wool fibers have long been used in home textiles and clothing, but their future looks even more promising with the growing consumer demand for natural, renewable, and sustainable materials. Beyond traditional clothing, wool is gaining increasing attention in the field of technical textiles due to its unique properties that make it suitable for a wide range of applications. As a natural and renewable fiber, wool offers benefits including tremendous moisture absorption, temperature law, and flame resistance, which make it a perfect material for technical textiles. In this study, two styles of Moroccan wool (Sardi and Timahdite), sourced from one-of-a-kind areas become accrued to explore their bodily and chemical homes and to investigate their capacity use within the manufacturing of nonwoven textiles for technical applications. Various analyses were carried out, inclusive of Fourier-remodel infrared spectroscopy and the Optical Fiber Diameter Analyzer, together with numerous check techniques based totally on global standards. These tests evaluated parameters which include grease content material, alkali content, acid content, solubility in alkali, and tensile strength. The results showed that Timahdite wool is the most suitable for nonwovens, way to its fineness and excessive absorbency compared with the Sardi wool.

Abstract: An advanced, eco-friendly, and fully bio-based flame retardant (FR) system has been created and applied to the cellulose structure of the cotton fabric through a layer-by-layer coating method. This study examines the flame-retardant mechanism of protein based and phosphorus containing coatings to improve fire resistance. During combustion, the phosphate groups (-PO₄²⁻) in phosphorus containing flame retardant layer interact with the amino groups (-NH₂) of protein, forming ester bonds which results in generation of crosslinked network between the amino groups and the phosphate groups. This structure greatly enhances the thermal stability of the residual char, hence, improving fire resistance. Tests such as the cone calorimeter and flammability tests show significant improvements in fire safety, including lower peak heat release rates, reduced smoke production, and higher char residue, all contributing to better flame-retardant performance. pHRR, THR and TSP of the flame-retarded cotton fabric demonstrated 25, 54 and 72% reduction, respectively. These findings suggest that LbL-assembled protein-phosphorus based coatings provide a promising, sustainable solution for creating efficient flame-retardant materials.

Abstract: This study evaluates the chemical, physical, mechanical, and biological properties of untreated and heat-treated Cryptomeria japonica wood from the Azores, Portugal. Heat treatment was performed at 212°C for 2 hours following the Thermo-D class protocol. Chemical analysis revealed an increase in ethanol extractives and lignin content after heat treatment, attributed to hemicellulose degradation and condensation reactions. Dimensional stability improved significantly, as indicated by reduced swelling coefficients and higher anti-swelling efficiency (ASE), particularly in the tangential direction. Heat-treated wood demonstrated reduced water absorption and increased density, enhancing its suitability for applications requiring dimensional stability. Mechanical tests showed a decrease in bending strength by 19.6% but an increase in the modulus of elasticity (MOE) by 49%, reflecting changes in the wood's structural integrity. Surface analysis revealed significant color changes, with darkening, reddening and yellowing, aligning with trends observed in other heat-treated woods. Biological durability tests indicated that both untreated and treated samples were susceptible to subterranean termite attack, although heat-treated wood exhibited a higher termite mortality rate, suggesting potential long-term advantages. This study highlights the impact of heat treatment on Cryptomeria japonica wood, emphasizing its potential for enhanced stability and durability in various applications.

Abstract: In this study, we explored the structural and chemical modifications of cellulose fibres subjected to chemical and mechanical treatments through an innovative analytical approach. We employed photoacoustic spectroscopy (PAS) and reversed double-beam photoacoustic spectroscopy (RDB-PAS) to examine the morphological changes and the chemical integrity of the treated fibres. The methodology provided enhanced sensitivity and specificity in detecting subtle alterations in the treated cellulose structure. Additionally, we applied Coifman wavelet transformation to the PAS signals, which facilitated a refined analysis of the spectral features indicative of chemical and mechanical modifications at a molecular level. This advanced signal processing technique allowed for a detailed decomposition of the PAS signals, revealing hidden characteristics that are typically overshadowed in raw data analyses. Further, we utilized the concept of energy trap distribution to interpret the wavelet-transformed data, providing insights into the distribution and density of energy states within the fibres. Our results indicated significant differences in the energy trap spectra between untreated and treated fibres, reflecting the impact of chemical and mechanical treatments on the fibre’s physical properties. The combination of these sophisticated analytical techniques elucidated the complex interplay between mechanical and chemical treatments and their effects on the structural integrity and chemical composition of cellulose fibres.

Abstract: 3D printing technology has made significant strides in smart textiles—fabrics embedded with electronics like conductive fibers and sensors—now widely applied in areas such as health con-dition monitoring, wearable energy-harvesting devices, and interactive textiles that respond to environmental conditions and color changes. Different 3D printing methods, such as Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), Direct Ink Writing (DIW), and PolyJet printing, are used in the fabrication of smart textiles. This study provides a detailed, applica-tion-specific overview of 3D printing technologies—such as FDM, SLS, DIW, and PolyJet print-ing—and their use in smart textiles across various sectors, including wearable technology, medical textiles, and smart fashion design. We gathered articles and reports from Scopus and Google Scholar, providing a concise assessment of 3D printing materials for smart textiles to give readers a quick understanding of the field. The timeline of 3D printing’s use in smart textiles, from 2016 to 2023, highlights significant advancements in various additive manufacturing techniques applied to smart textiles. The review emphasizes the importance of understanding 3D printing techniques such as FDM, SLS, DIW, and PolyJet, as their applicability for selecting the best approach to in-corporating advanced functionalities into smart textiles.

Abstract: Handmade papers, as carriers of paper-based cultural relics, have played a crucial role in the development of human culture, knowledge, and civilization. Understanding the intricate relationship between the structural properties and degradation mechanisms of handmade papers is essential for the conservation of historical documents. In this work, an artificial dry-heat accelerated ageing method was used to investigate the interplay between the mechanical properties of paper, the degree of polymerization (DP) of cellulose, chemical composition, hydrogen bond strength, crystallinity, and degree of hornification. The results show that the mechanical properties of handmade bamboo paper exhibited a first plateau region, a rapid decline region, and sometimes a second plateau region. A critical point in the mechanical properties of the paper occurs when the cellulose DP decreases to a range of 400-600, signifying a shift from the initial plateau to a sharp decline phase. The strengthening of intermolecular hydrogen bonds and the hornification process help counteract the embrittlement of fibers caused by cellulose chain scission due to DP reduction. A secondary plateau emerges when the DP is smaller than 400, cellulose degradation is slow, and the component content, hydrogen bond strength, crystallinity, and degree of hornification reach a secondary plateau.

Abstract: Corner joints and edge banding play crucial roles in the strength, durability, and aesthetics of furniture made from particleboards. This review highlights the importance of edge banding on corner joints in enhancing the overall quality of panel furniture. The choice of joint type, materials, and construction techniques can significantly influence the overall appearance and design of the furniture. The quality and design of corner joints directly affect the durability and longevity of furniture. Strong and well-designed corner joints ensure that furniture can withstand various forces and loads without failure or deformation. In addition, corner joints contribute to the aesthetics of furniture by providing seamless and visually appealing connections between different elements. Edge banding plays a crucial role in influencing the strength of corner joints in the furniture. Different edge-banding materials have varying levels of resistance to impact, scratches, and abrasion, which protect furniture surfaces. Overall, edge banding not only enhances the visual appeal of furniture, but also ensures its durability and longevity, both in the service of its purpose and during disassembly and/or transport due to the remodeling of the living space or its relocation. The findings aim to unify the knowledge and set parameters for further research on the quality of corner joints and edge bands in particleboard furniture.

Abstract: The growing prevalence of disposable toilet seat covers in public restrooms stems from concerns about personal hygiene, given the direct contact between the seat and various users' skin. To enable flushing these disposable cover sheets down the toilet instead of discarding them in the trash, they must possess specific properties. These include rapid water absorption for quick disintegration, strength to endure user movement or moisture on the toilet seat surface, and a comfortable texture. To address these challenges, the study investigated the disintegration characteristics of flushable cover sheets prepared under different refining conditions. Alkyl ketene dimer (AKD) was also employed to enhance water resistance, while an organic antibacterial agent was used to impart antimicrobial properties. The findings revealed that adding 0.2% AKD and 1% organic antibacterial agent to pulp stock with a freeness of about 650 mL CSF was suitable for manufacturing disposable cover sheets with disintegration characteristics like toilet tissue paper.

Abstract: The purpose of this work is to analyze heat-treated ash wood at temperature of 185 ºC, in order to analyze its dimensional stability. For comparison, native ash/ not thermally treated wood, was be used. In order to analyze heat-treated ash wood, some main properties such as water absorption, swelling in thickness, roughness, Brinell hardness, modulus of rupture and elasticity, color change toward black with CIELab space, and many others properties were determined and processed. The results obtained after processing the experimental data have showed that heat-treated ash wood had good physical properties as absorption and swelling in thickness, and the slight increase in elasticity offers new fields of use. As a general conclusion of the work, it was established that the ash wood can be properly thermally treated, the dimensional stability characteristics being very good, and the decrease in bending resistance being almost imperceptible.

Abstract: The increasing environmental awareness and carbon-storing capability of wood have amplified its relevance as a building material. The demand for high-quality wood species necessitates exploring alternative, underutilized wood sources due to limited forest areas and premium wood volume. Consequently, the veneer-based industry is considering lower-value hardwood species like grey alder, black alder, and aspen as substitutes for high-quality birch. Initially less appealing due to their lower density and mechanical properties, these species show promise through densification, which enhances their density, strength, and hardness. This study aims to enhance plywood screw withdrawal capacity and surface hardness by densifying low-density wood species and using them in plywood face veneer layers or all layers. The relationship between wood density, surface hardness, and screw withdrawal capacity of plywoods made of low-value species like aspen and black alder is examined. Experimental work with a pilot-scale veneer and plywood production line demonstrates improved surface hardness (65% and 93% for aspen and black alder, respectively) and screw withdrawal capacity (16% and 35% for aspen and black alder, respectively) in face veneer densified low-value hardwood plywood. This research highlights the potential of densified low-value wood species to meet construction requirements, expanding their practical applications.

Abstract: The wood-based panel industry is experiencing an excessive accumulation of solid residues from the production of medium-density fiberboard (MDF) panels and moldings. It is possible to create new MDF products with acceptable physical and mechanical properties by revaluing MDF residues. Additionally, those products’ thermal properties can be improved by incorporating phase change materials (PCMs). This study aims to develop a wood-based fiberboard made of MDF residues, capable of storing thermal energy. Two types of PCMs, two PCM ratios, and two types of adhesives were used to produce eight different types of panels. The vertical density profile, thickness swelling, water absorption, internal bond (IB), and static bending properties – modulus of elasticity (MOE) and modulus of rupture (MOR) – were determined for each panel type. The specific heat of the panels was also determined. The results show the panels’ densities were greater than 700 kg/m3. Thickness swelling in water improved by 23% compared to the reference value of the control panel PCMs after PCM incorporation. The highest IB value was 1.30 MPa, which is almost three times the minimum required by regulation standards. The incorporation of PCMs reduced the panels’ bending properties compared to the properties of the control panels. Even though the values obtained are sufficient to comply with the minimum values set out in ANSI standard A208.2 with a MOE value of 2072.4 MPa and the values obtained are sufficient to comply with the minimum standards with a MOE value of 2072.4 MPa and a MOR value of 16.4 MPa. When microencapsulated PCM is used, the specific heat of the panels is increased by more than 100% over that of the control panels. This study develops a feasible alternative for using MDF residues: to create fiberboard that is capable of storing thermal energy and has adequate physical and mechanical properties.

Abstract: Elastic yarns are the key component of high-performance compression garments. However, it remains a challenge to fabricate anti-fatigue yarns with high mechanical force and long elongation for generating compression garments with prolonged wear. In this paper, we report the development of anti-fatigue double-wrapped yarns with excellent mechanical properties by wrapping high-denier Spandex with nylon filaments in opposite twists. In particular, 560D high-denier Spandex as the core was untwisted which can maximumly reduce the interaction between the core and wrapping filaments, enabling high elongation of the double-wrapped yarns. In addition, we chose 70D nylon filaments with a tensile force of 387.40 ± 8.82 cN as the wrapping materials to provide sufficient force for double-wrapped yarns. Notably, opposite twists were induced for the inner and outer wrapping filaments to achieve a balanced stable yarn structure. By systematically optimizing manufacturing parameters including inner wrapping density, outer wrapping density, taking-up ratio, and drafting ratio, we obtained double-wrapped yarn with excellent tensile force (952.00 ± 24.03 cN) and elongation (357.28% ± 9.10%). Notably, the stress decay rate of optimized yarns was only 12.0% ± 2.2%. In addition, the optimized yarn was used as the weft-lining yarn for generating weft-lined fabrics, the elastic recovery rate of the obtained fabric was only 2.6% after cyclic stretching, much lower than the control fabric. Our design of anti-fatigue double-wrapped yarns could be widely used for fabricating high-performance compression garments.

Abstract: Fires constitute a significant threat due to the pollutants emitted and the destruction they cause. People who take part in fire-fighting operations must be equipped with appropriate tools, including special clothing that will allow them to work and guarantee safety. One of the threats are compounds from the PAH group, which are characterized by high toxicity and carcinogenicity. Therefore, it is important that the materials used constitute a barrier to contamination. Various materials from which individual elements of special firefighter's clothing are made were tested. Additionally, the importance of height on the possibility of sorption of PAH compounds on a given type of material was analyzed. Based on the results obtained, it was found that the type of material and the zone in which the clothing items are used are important in the sorption processes of pollutants. Data in this area may be important for taking further actions regarding the modification of materials used in special fire brigade clothing and in their cleaning processes.