Improving Fire Retardancy of Beech Wood by Graphene

Exploring the optical properties of naphdiyne sheet: First-principles study

Naphdiyne sheet is a two-dimensional carbon-based structure composed of naphthyl rings and acetylenic linkages. The optical characteristics of naphdiyne sheets are investigated using density functional theory. The results showed that this sheet is suitable for energy storage systems due to its high dielectric constant. The dielectric constant of naphdiyne is higher than that of graphene. The refractive index, absorption, reflection, and transmission coefficients are calculated based on the dielectric function. A notable optical absorption is observed across a wide energy range for parallel polarization. The transparency of this material is evident in its reflection and transmission constants, particularly in high-energy regions. The findings suggest that the naphdiyne sheets hold promise for use in nanoelectronics and optoelectronics.

Nanotechnology in wood science: Innovations and applications

Application of nanomaterials is gaining tremendous interest in the field of wood science and technology for value addition and enhancing performance of wood and wood-based composites. This review focuses on the use of nanomaterials in improving the properties of wood and wood-based materials and protecting them from weathering, biodegradation, and other deteriorating agents. UV-resistant, self-cleaning (superhydrophobic) surfaces with anti-microbial properties have been developed using the extraordinary features of nanomaterials. Scratch-resistant nano-coatings also improve durability and aesthetic appeal of wood. Moreover, nanomaterials have been used as wood preservatives for increasing the resistance against wood deteriorating agents such as fungi, termites and borers. Wood can be made more resistant to ignition and slower to burn by introducing nano-clays or nanoparticles of metal-oxides. The use of nanocellulose and lignin nanoparticles in wood-based products has attracted huge interest in developing novel materials with improved properties. Nanocellulose and lignin nanoparticles derived/synthesized from woody biomass can enhance the mechanical properties such as strength and stiffness and impart additional functionalities to wood-based products. Cellulose nano-fibres/crystals find application in wide areas of materials science like reinforcement for composites. Incorporation of nanomaterials in resin has been used to enhance specific properties of wood-based composites. This review paper highlights some of the advancements in the use of nanotechnology in wood science, and its potential impact on the industry.

Comprehensive Review of Recent Research Advances on Flame-Retardant Coatings for Building Materials: Chemical Ingredients, Micromorphology, and Processing Techniques

Developing fire-retardant building materials is vital in reducing fire loss. The design and preparation of novel fire-retardant coatings merely require the adhesion of flame retardants with high fire-retardant characteristics on the surface, which is significantly more economical than adding excessive amounts of flame retardants into bulk building materials. Meanwhile, fire-retardant coating has excellent performance because it can block the self-sustaining mechanisms of heat and mass transfer over combustion interfaces. In recent years, research of fire-retardant coatings for building materials has been subject to rapid development, and a variety of novel environmentally benign fire-retardant coatings have been reported. Nonetheless, as the surface characteristics of various flammable building materials are contrastively different, selecting chemical ingredients and controlling the physical morphology of fire-retardant coatings for specific building materials is rather complicated. Thus, it is urgent to review the ideas and preparation methods for new fire-retardant coatings. This paper summarizes the latest research progress of fire-retardant building materials, focusing on the compositions and performances of fire-retardant coatings, as well as the principles of their bottom-up design and preparation methods on the surface of building materials.

Fabrication of Inorganic Coatings Incorporated with Functionalized Graphene Oxide Nanosheets for Improving Fire Retardancy of Wooden Substrates

Flame-retardant chemicals are frequently used within consumer products and can even be employed as a treatment on the surface of different types of materials (e.g., wood, steel, and textiles) to prevent fire or limit the rapid spread of flames. Functionalized graphene oxide (FGO) nanosheets are a promising construction coating nanomaterial that can be blended with sodium metasilicate and gypsum to reduce the flammability of construction buildings. In this work, we designed and fabricated novel and halogen-free FGO sheets using the modified Hummers method; and subsequently functionalized them by pentaerythritol through a chemical impregnation process before dispersing them within the construction coating. Scanning electron microscopic images confirm that the FGO-filled coating was uniformly dispersed on the surface of wooden substrates. We identified that the FGO content is a critical factor affecting the fire retardancy. Thermogravimetric analysis of the FGO coating revealed that higher char residue can be obtained at 700 °C. Based on the differential scanning calorimetry, the exothermic peak contained a temperature delay in the presence of FGO sheets, primarily due to the formation of a thermal barrier. Such a significant improvement in the flame retardancy confirms that the FGO nanosheets are superior nanomaterials to be employed as a flame-retardant construction coating nanomaterial for improving thermal management within buildings.

Ammonium Polyphosphate Intercalated Yttrium-Doped Layered Double Hydroxides to Enhance the Thermal Stability and Flame Retardancy of Poly(Lactic Acid)

The flammability of the biodegradable plastic PLA limits its application in industrial fields with high flame-retardant requirements. This paper provides a novel strategy for constructing refractory and thermostable PLA composites using layered double hydroxides (LDHs) chemically modified with ammonium polyphosphate (APP). XRD, FT-IR, SEM-EDS, and TEM confirm that the goal of LDHs has been successfully prepared. The thermal stability and combustion behavior of PLA composites were evaluated by the thermogravimetric analysis (TGA) and cone calorimetry tests (CCT). The crystallization behavior and tensile performances were also examined. The results showed that the incorporation of 15 wt% MgAlY-APP-LDHs practically makes the PLA composites reach the UL-94 V-0 grade. There were 43% and 20% reduction in the PHRR and THR of PLA/15APP-LDHs respectively due to the catalytic effect of Y elements and barrier effects of LDHs, which was a major performance against fire hazards. Furthermore, the increase in crystallinity and the decrease in mechanical strength of PLA composites are attributed to the nucleation of LDHs. In short, this research introduces the production of multifunctional PLA composites through APP intercalation of LDHs, which are deemed as prospective candidates for the next generation of sustainable plastics products.

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing. However, in order to have a positive impact on the society, these surface improvements must be applied in real buildings. In this review, the last five years of research in the domain of wood surface improvements and modifications is first presented by sorting the latest innovations into different trends. Afterward, these trends are correlated to specifications representing different normative, ecologic and economic factors which must be considered when expecting to introduce a wood treatment to the market. With this review, the authors hope to help researchers to take into consideration the different factors influencing whether new innovations can leave the research laboratory or not, and thereby facilitate the introduction of new wood surface treatments in the society.

Effects of Wollastonite on Fire Properties of Particleboard Made from Wood and Chicken Feather Fibers

The present study was carried out primarily to investigate the fire properties of particleboards with 5% and 10% feather content. With regard to the flammability of chicken feathers, separate sets of panels were produced with 10% wollastonite content to determine to what extent it could help mitigate the negative effects of the addition of flammable feathers on the fire properties. It was concluded that the inclusion of 5% of chicken feathers can be considered the optimum level, enough to procure part of the ever-growing needs for new sources of raw material in particleboard manufacturing factories, without sacrificing the important fire properties. Moreover, the addition of 10% wollastonite is recommended to significantly improve the fire properties, making the panels more secure in applications with higher risks of fire. It is further stated thata chicken feather content of 10% is not recommended as it significantly deteriorates all properties (including physical, mechanical, and fire properties).

Application of Nanotechnology in Wood-Based Products Industry: A Review

Wood-based industry is one of the main drivers of economic growth in Malaysia. Forest being the source of various lignocellulosic materials has many untapped potentials that could be exploited to produce sustainable and biodegradable nanosized material that possesses very interesting features for use in wood-based industry itself or across many different application fields. Wood-based products sector could also utilise various readily available nanomaterials to enhance the performance of existing products or to create new value added products from the forest. This review highlights recent developments in nanotechnology application in the wood-based products industry.

Formaldehyde Emission in Micron-Sized Wollastonite-Treated Plywood Bonded with Soy Flour and Urea-Formaldehyde Resin

Soy flour was partly substituted for urea-formaldehyde (UF) resin with different content to investigate its effect on formaldehyde emission in three-layer plywood panels. In each square meter of panels, 300 g of resin was used (wet weight basis of resin). Micron-sized wollastonite was added to the resin mixture at 5% and 10% consumption levels (wet weight basis of resin) to determine its potential effects as a reinforcing filler to mitigate the negative effects of addition of soy flour. Results showed a decreasing trend in formaldehyde emission as soy flour content increased to 20%. The highest shear-strength values were observed in panels with 10% and 15% soy flour content. The addition of wollastonite did not have a significant effect on formaldehyde emission, but it decreased the shear strength in soy-treated panels, although the values were still higher than those of control panels. Wollastonite significantly mitigated the negative effects of soy flour on the water absorption and thickness swelling of panels. It was concluded that 10% of soy flour and 5% of wollastonite provided the lowest formaldehyde emission and the most optimum physical and mechanical properties.

Hazards Resulting from the Burning Wood Impregnated with Selected Chemical Compounds

In the construction industry, a variety wooden products have been used for thousands of years, according to demand, accessibility/availability, and customers’ requirements. Wood is a preferred material due to its large range of properties, depending on the type of wood. It is an easily available and economically competitive material, and it is also extremely strong in relation to its weight. Therefore, it is used in the production of construction materials, building parts, and finishing components, as well as for furniture and decorative elements. Each of these products is commonly additionally chemically treated in order to improve its performance parameters. However, impregnated wooden products such as furniture and fence boards are often misused, including for house heating, waste incineration, bonfires, etc. For this reason, among the products of combustion, there is a whole range of different chemical compounds, frequently carcinogenic, and dangerous for health and the environment, for example, heavy metals. Knowledge in this field is important for professions, such as: firefighter, lifeguard, people dealing with environmental management, and units responsible for waste landfills. On the other hand, important recipients of this information are ordinary residents who, due to a lack of knowledge, use such materials as e.g., heating material.

Advances in Wood Composites II

The main advantage of wood composites is that they can be designed for specific performance requirements or specific qualities, since they are man-made [...].

Potential Use of Wollastonite as a Filler in UF Resin Based Medium-Density Fiberboard (MDF)

Urea-formaldehyde (UF) resins are primary petroleum-based, increasing their potential environmental footprint. Identifying additives to reduce the total amount of resin needed without adversely affecting the panel properties could reduce these impacts. Wollastonite is a mineral containing calcium and silica that has been used as an additive in a variety of materials and may be useful as a resin extender. Nanoscale wollastonite has been shown to enhance the panel properties but is costly. Micron-scale wollastonite may be a less costly alternative. Medium-density fiberboards were produced by blending a hardwood furnish with UF alone, micron-sized wollastonite alone, or a 9:1 ratio of UF to wollastonite. Panels containing of only wollastonite had poor properties, but the properties of panels with 9:1 UF/wollastonite were similar to the UF-alone panels, except for the internal bond strength. The results suggest that small amounts of micron-sized wollastonite could serve as a resin extender. Further studies are suggested to determine if the micron-sized material has similar positive effects on the resin curing rate.

Heat Treatment of Pine Wood: Possible Effect of Impregnation with Silver Nanosuspension

The scope of the present work was to study the effects of heat treatment (at different mild temperatures) on the physicomechanical properties of pine wood, and to find out if impregnation with nanosilver may have any potential influence on the impact of heat treatment. Impregnation of wood with a 400-ppm silver nanosuspension was carried out under an initial vacuum pressure of 0.07 MPa, followed by a pressure of 0.25 MPa for thirty minutes, before heat treatment. Heat treatment was carried out under hot air at three relatively mild temperatures, 145, 165, and 185 °C. Results showed improvement of some properties in heat-treated wood at 145 °C. This was indicative of the improving impact caused by hornification and irreversible hydrogen bonding in the course of water movements due to heat treatment; significant fluctuations in the intensities of FTIR spectra bands at 1750–1500 cm−1 were corroborating evidence of chemical alterations in hemicellulose polymer. The high mass loss at temperature 185 °C, and the extreme thermal degradation thereof, overcame the improving effects of hornification and formation of irreversible hydrogen bonds, consequently mechanical properties decreased significantly. Interaction of different elements involved made it hard to predict properties in specimens modified at 165 °C. Impregnation of specimens with nanosilver suspension resulted in significant increase of mass loss in specimens heat-treated at 185 °C, and significant fluctuations in properties of specimens heat-treated at 145 °C.

Engineering Composites Made from Wood and Chicken Feather Bonded with UF Resin Fortified with Wollastonite: A Novel Approach

Wood-composite panel factories are in shortage of raw materials; therefore, finding new sources of fibers is vital for sustainable production. The effects of chicken feathers, as a renewable source of natural fibers, on the physicomechanical properties of medium-density fiberboard (MDF) and particleboard panels were investigated here. Wollastonite was added to resin to compensate possible negative effects of chicken feathers. Only feathers of the bodies of chickens were added to composite matrix at 5% and 10% content, based on the dry weight of the raw material, particles or fibers. Results showed significant negative effects of 10%-feather content on physical and mechanical properties. However, feather content of 5% showed some promising results. Addition of wollastonite to resin resulted in the improvement of some physical and mechanical properties. Wollastonite acted as reinforcing filler in resin and improved some of the properties; therefore, future studies should be carried out on the reduction of resin content. Moreover, density functional theory (DFT) demonstrated the formation of new bonds between wollastonite and carbohydrate polymers in the wood cell wall. It was concluded that chicken feathers have potential in wood-composite panel production.