Green flame retardancy: biomass-based treatment for poplar wood

The development of fire retardants (FRs) is an approximative process of optimization. In this context, a novel water-soluble formulation with poly(sodium silicate-aluminum dihydrogen phosphate) (PSADP) has been developed, aiming at reduced hygroscopicity and enhanced leaching resistance of poplar wood in combination with nitrogen-phosphorus (NP) FR (FRNP). After treatment of wood with FRNP and PSADP in vacuum, the following data of the samples were determined: rate of hydroscopicity, leaching resistance, heat release rate (HRR), total HR (THR), effective combustion heat, mass loss, and concentration of flue gas. FR distribution in the wood’s inner surface was investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA). Results show that PSADP and FRNP have favorable synergistic effects on moisture resistance and flame retardance. Smoke density (SD) of NP and PSADP treated samples shows a significant reduction relative to that of NP. NP-PSADP treated samples form more char with carbon layers of higher density. At the same time, FRNP-PSADP is evenly distributed over the inner wood surfaces and penetrates the cell cavities of the poplar wood.

The problem of using wood is to ensure resistance to high-temperature flame and application technology. Therefore, the object of research was to change the parameters of thermal destruction of wood during fire protection by impregnation and intumescent coating. It has been proven that for wood treated by impregnation, the destruction processes slow down, so the mass loss is reduced by 3–5 times, the process increases in the region of higher temperatures with a significant coke residue. As for wood treated with intumescent coating, in the temperature range of 200–300 °C, pentaerythritol begins to decompose with the formation of aldehydes and a foam coke center is formed. The beginning of intensive mass loss coincides with the temperature of 320–330 °C, on which the sublimation peak of melamine is superimposed, starting at a temperature of 330 °C, which ends at a temperature of more than 420 °C. The obtained activation energy of wood is 30.03 kJ/mol, treatment of wood with impregnating agents increases the activation energy during its thermal decomposition by more than two times, and treatment with an intumescent coating by more than 4.4 times. After pyrolysis of wood treated with flame retardants, the mixtures of destruction products differ significantly in the content of carbon dioxide, nitrogen and the amount of combustible gases. Thus, for wood treated with the composition DSA-1, the amount of nitrogen increased by more than 46 times, and the amount of combustible gases decreased by more than 3 times. An even greater difference was recorded during treatment of wood with an intumescent coating. In particular, it was found that the amount of combustible gases decreased by more than 4 times, and the amount of nitrogen increased by more than 56 times. The practical significance lies in the fact that the results obtained were taken into account when developing a reactive coating. Thus, there are grounds to argue about the possibility of directed regulation of the wood protection process through the use of coatings capable of forming a protective layer on the surface.

Currently, the demand for timber is increasing. Wood and products on its basis are considered to be the most popular in the construction industry, furniture industry, as building materials and other However, along with the positive features of this material there are also negative factors, which include low resistance to biological degradation, high temperature, resistance. Wood and materials based on it are the most flammable, and fire safety is characterized by the velocity of propagation of fire on the wooden structure. He is able to destroy it in a matter of minutes. So the wooden house elements must be protected from fire. It was therefore necessary for the fire protection of wood. It is in the handling of wood with flame retardants. Basic fire fighting methods is the impregnation of wood antipyrene composition, painting fire paint and constructive ways - insulation of timber, non-combustible compositions which can resist the fire. In the work of brominated 4-vinylcyclohexane formed as a by-product in the petrochemical industry, in chloroform synthesized compound with bromine 62-64 % and the possibility of using this product to get antiferromag composition. It is established that the application for the protective treatment of wood synthesized flame retardant has shown that this product can be used for the protective treatment of natural wood to make it flame retardant properties. Use as antiperiodic compositions bromodomain based products 4-vinylcyclohexane allows to obtain images of wood first group of flame retardant efficiency.

BackgroundOrganohalogen compounds (OHCs) are known to have neurotoxic effects on the developing brain.ObjectiveWe investigated the influence of prenatal exposure to OHCs, including brominated flame retardants, on motor, cognitive, and behavioral outcome in healthy children of school age.MethodsThis study was part of the prospective Groningen infant COMPARE (Comparison of Exposure-Effect Pathways to Improve the Assessment of Human Health Risks of Complex Environmental Mixtures of Organohalogens) study. It included 62 children in whose mothers the following compounds had been determined in the 35th week of pregnancy: 2,2′-bis-(4 chlorophenyl)-1,1′-dichloroethene, pentachlorophenol (PCP), polychlorinated biphenyl congener 153 (PCB-153), 4-hydroxy-2,3,3′,4′,5-pentachlorobiphenyl (4OH-CB-107), 4OH-CB-146, 4OH-CB-187, 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), BDE-99, BDE-100, BDE-153, BDE-154, and hexabromocyclododecane. Thyroid hormones were determined in umbilical cord blood. When the children were 5–6 years of age, we assessed their neuropsychological functioning: motor performance (coordination, fine motor skills), cognition (intelligence, visual perception, visuomotor integration, inhibitory control, verbal memory, and attention), and behavior.ResultsBrominated flame retardants correlated with worse fine manipulative abilities, worse attention, better coordination, better visual perception, and better behavior. Chlorinated OHCs correlated with less choreiform dyskinesia. Hydroxylated polychlorinated biphenyls correlated with worse fine manipulative abilities, better attention, and better visual perception. The wood protective agent (PCP) correlated with worse coordination, less sensory integrity, worse attention, and worse visuomotor integration.ConclusionsOur results demonstrate for the first time that transplacental transfer of polybrominated flame retardants is associated with the development of children at school age. Because of the widespread use of these compounds, especially in the United States, where concentrations in the environment are four times higher than in Europe, these results cause serious concern.

Enhancing water resistance and flame retardancy of wood through phytic acid catalyzed in-situ polyesterification

Hybrid poplar (Populus deltoides × Populus trichocarpa) and Douglas-fir (Pseudotsuga menziesii) wood specimens were densified with three variations of thermo-hydro-mechanical (THM) treatment. The THM treatments differed in the steam environment, including transient steam (TS), saturated steam (SS), and saturated steam with 1-min post–heat treatment at 200 °C (SS+PHT). The bending properties, FTIR spectra, and colour of the THM wood specimens were studied before and after exposure to two different wood decay fungi, brown rot Gloeophyllum trabeum, and white rot Trametes versicolor. The results showed that the performance of densified hybrid poplar wood was considerably poorer than the performance of Douglas-fir heartwood. The FTIR spectra measurements did not show changes in the densified hybrid poplar wood, while some changes were evident in densified Douglas-fir specimens. After fungal degradation, the most prominent changes were observed on the SS+PHT specimens. Colour is one of the most important parameter predominantly influenced by the wood species and the intensity of the densification process for both wood species, while after fungal exposure, the colour of all densified Douglas-fir specimens obtained more or less the same appearance, and densified hybrid poplar specimens resulted in lighter colour tones, indicating that the pattern of degradation of the densified and non-densified specimens are similar. The 3-point bending test results determined that the THM treatment significantly increased the modulus of rupture (MOR) and modulus of elasticity (MOE) of the densified wood specimens, while fungal exposure decreased the MOE and MOR in hybrid poplar and Douglas-fir specimens.

A novel two-step combined treatment of poplar wood was developed to improve its dimensional stability. Maleic anhydride (MAN) was first employed to swell and bond to the wood cell wall, and then mixed monomers of glycidyl methacrylate/methyl methacrylate (GMA/MMA) were grafted to the cell wall through the chemical reaction with MAN within the wood cell lumen. The results of scanning electron microscopy and energy dispersive X-ray apparatus (SEM-EDX) and Fourier transform infrared spectroscopy (FTIR) analyses indicate that MAN penetrated and chemically bonded to the cell wall causing 9% volume swelling, and the copolymer from GMA/MMA monomers was grafted onto the wood cell wall, resulting in the improved interfacial compatibility between the polymer and wood matrix. The dimensional stability of poplar wood modified by the combined two-step treatment was remarkably improved compared with that of untreated poplar wood. The combination treatment of wood employed in this study proved to be more effective for improving the dimensional stability than treatment with PEG-1000 aqueous solution with 30% concentration.

With the high quality natural forest resources dwindling , since some species of wood with natural colors, such as pumping wood , ebony, rosewood , etc., not only material of high value , but also very expensive wood color . However, these are expensive and precious wood in short supply and will therefore valuable timber and wood stain to meet the market demand is similar . Low-quality hardwood stained only bright color, texture clear , three-dimensional sense of strong, but without losing the characteristics of natural wood , and organize production according to market demand the formation of industrialized products in order to improve the utilization of low-quality wood , decorative building materials to increase the existing varieties purposes. Therefore, the use of poplar simulate the market needed precious wood has important practical significance . In addition, light color white poplar wood , in the natural growth process still exists heartwood and sapwood and sooner or later material defects such as chromatic aberration , especially wood treatment is not promptly will result in discoloration, the direct use of the logs are often unable to meet the requirements of decoration . Therefore . The thicker sheet dyed precious poplar wood color , and then prepared to meet the customer poplar wood timber strength and decorative requirements, improve the added value of the use of wood , particularly after dyeing material available performance has been greatly improved.

Magnetic solid phase extraction of brominated flame retardants and pentachlorophenol from environmental waters with carbon doped Fe3O4 nanoparticles

Melamine-Formaldehyde Acrylamide and Gum Polymer Impregnated Wood Polymer Nanocomposite

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.

SummaryWood products are often treated by different techniques to improve their longevity when used as building materials. Most of the time, the goal is to increase their resistance to weathering effects, deformations in material dimensions or biotic decomposition. These wood treatment techniques have a significant impact on pyrolysis and burning behavior. The general effects of three different common wood treatments on flame retardancy were investigated by comparing treated woods with their untreated counterparts and with other kinds of wood. While the acetylation of beech leads to a slightly increased fire hazard, the thermal treatment of wood and crosslinking of cellulose microfibrils dimethyloldihydroxy‐ethyleneurea show a limited flame retarding effect. Switching to woods with a higher lignin content, and thus higher char yield, however, results in a more pronounced improvement in flame retardancy performance. This article delivers a comprehensive and balanced assessment of the general impact of different wood modifications on the fire behavior. Further, it is a valuable benchmark for assessing the flame retardancy effect of other wood modifications.

Flow chemistry for a better fractionation of lignocellulosic biomass in products structure and yield

Poplar wood was subjected to biological treatment with a white-rot fungus Trametes hirsuta C7784. The structural features of the lignin in the untreated and treated poplar wood samples were comparatively elucidated. Milled wood lignin (MWL) and residual enzymatic lignin (REL) fractions of each sample were sequentially isolated. The total pure yields of the isolated lignin fractions after white-rot fungus treatment exceeded 96% (based on the Klason lignin content), and thus, represented the whole lignin in the fungus-treated poplar wood. The structural features of the lignin fractions were quantitatively analyzed. β-O-4′ structures were the most prominent linkage in the biologically treated wood, and there were more present than in the untreated wood. To this effect, the lignin in the fungus-treated poplar wood was easily degraded and removed under mild conditions, which is essential for subsequent conversion processes.

Experimental analysis of thermally-treated Chinese poplar wood with focus on structural application