Wood Composite Materials Research Articles

Wood Composites with Wettability Patterns Prepared by Controlled and Selective Chemical Modification of a Three-Dimensional Wood Scaffold

Wood-composite materials with patterned wetting properties were synthesized by applying hydrothermal growth of ZnO rods into a wood scaffold. We exploited the natural morphological features of wood, to selectively modify the wood material via a self-directed deposition of ZnO in the biological scaffold. Characterizations using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction confirmed the successful surface modification and revealed the predominant growth of ZnO rods on earlywood (EW) regions. The wetting properties of these new wood-composite materials have been extensively investigated to study the influence of the grooved wood surface structure and its chemical heterogeneity on the wettability. We demonstrate that the ZnO–wood samples have alternating hydrophilic and hydrophobic “strips”, corresponding to the EW and latewood grains from the native wood, and that the surfaces are endowed with an interesting anisotropic wetting property. Using these special...

Isolation of lignocellulose nanofibrils (LCNF) and application as adhesive replacement in wood composites: example of fiberboard

Thermomechanical pulp (TMP) produced using atmospheric refining was ground to isolate lignocellulose nanofibrils (LCNF). Forty minutes and a specific energy of about 1300 kWh/t were necessary to reach the end-point of the process defined by the presence of 95% fines in the slurry. 100% fines were reached after 90 min and 5800 kWh/t. The similarity in structure between pilot-scale produced reference cellulose nanofibrils (CNF) and LCNF with an average fibril diameter of 12 nm confirmed the negligible effect of residual lignin on the defibrillation process. The thermal stability of LCNF was found to be 30 °C lower compared to that of CNF due to the lignin influence, but it was in the range of processing temperatures used for wood composite materials. The effect of using LCNF as adhesive replacement in fiberboard has been assessed. A maximum modulus of rupture of 12.1 MPa comparable to that of commercial fiberboards and high modulus of elasticity, was obtained at 20% LCNF content for panels produced at 180 °C. The binding ability of LCNF and its effect on the mechanical properties of fiberboards were more perceptible when a less refined TMP with lower fine content and longer fibers was used in the process.

Creation of density distribution charts in the cross and axial section of a tree trunk- Short Communication

The purpose of this paper is to develop a method of constructing density distribution charts in roundwood log based on the density values obtained with a resistograph. The problem of improving the performance properties of structures made of wood and wood-based composite materials and laminated products is particularly relevant for construction in the northern regions. The experience of building in Yakutia shows sufficient reliability and durability of structures made of larch wood, despite the fact that their use is associated with technological challenges: larch planks warp and crack during the drying process; rigidity of wood increases. These disadvantages are caused by the structural features of the wood material; the degree of their intensity is proportional to the index of wood density. This paper presents the methods and results of qualitative research on wood indices obtained in laboratory and field conditions, as well as the authors' methods of graphical representation of density distribution in the cross and axial sections of a tree trunk, which are based on measurements taken via the method of oriented drilling. In the experimental studies, we performed a comparative analysis of the two-dimensional charts of density distribution with the charts of velocity distribution of acoustic pulses produced by a sonic tomograph "Arbotom". The elaborated method of evaluating the quality indicators of forest resources contributes to the expansion of the boundaries of wood-based material utilization, reduces their cost and improves the quality of construction of wooden structures and buildings.

The Study of Wood-Based Composites Based on Biodegradable Polymer

The article presents the wood composite materials based on biodegradable component of polyvinyl acetate with the filler in a form of wood flour of pine trees of two types: unmodified and thermally modified pine. The sorption properties of composite of both species, namely the ability of a material to absorb moisture depending on the quantity and nature of wood filler were studied. The strength characteristics of composite materials with non-modified and modified wood fillers were investigated and revealed. The research of the loss of relative weight of both types of composite materials while standing in soil was conducted.The expediency of preliminary heat treatment of wood filler on politely if necessary some increase in biostability of the composite is found.

Experimental Study on Tensile and Compressive Strength of Bamboo Scrimber

The objective of this study was to provide fundamental parameters for the utilization of bamboo scrimber in the building structure field as a green building material. Both static tensile and compressive tests were conducted on bamboo scrimber, with 180 specimens for compressive tests and 173 specimens for tensile tests. The normal and lognormal distributions were selected to fit the experimental data. The design values were calculated according to the Chinese allowable stress design method and ASTM D2915 (2003). The results showed that both tensile strength (UTS) and compressive strength (CS) parallel to the fiber of bamboo scrimber were significantly higher than those of wood and other bamboo-based composite materials. Kolmogorov-Smirnov and chi-squared test results indicated that a lognormal distribution was a good fit for the UTS and CS except for the fitting result of UTS by the chi-squared test. The calculated design values of UTS and CS using ASTM D2915 (2003) were higher compared with those found using the Chinese allowable stress design method.

Determining shear modulus of thin wood composite materials using a cantilever beam vibration method

Shear modulus (G) of thin wood composite materials is one of several important indicators that characterizes mechanical properties. However, there is not an easy method to obtain this value. This study presents the use of a newly developed cantilever beam free vibration test apparatus to detect in-plane G of thin wood composite materials by measuring the first order free vibration cantilever specimens and its logarithmic decrement of vibration. Six sets of commercially purchased thin wood composite materials having three different fiber types were tested. A significant linear correlation was found between in-plane G and bending modulus of elasticity (MOE) from cantilever-beam free vibration test and MOE was shown to be approximately two times of in-plane G. This was in full agreement with previous findings by other researchers. The study demonstrated that the cantilever beam free vibration method could be widely used to obtain in-plane G easily for thin wood composite materials.

Some technological properties of poplar plywood panels reinforced with glass fiber fabric

The reinforcement of solid wood and wood-based composite materials is not a new idea, but there have been very few studies about reinforcing poplar plywood with glass fiber fabric using phenol formaldehyde. In this study, plywood panels were produced using poplar veneer and phenol formaldehyde adhesive and glass fiber fabric. One control group and three different test groups were set up. In addition, perpendicular and parallel test samples for each group were set up for bending tests. Some of the physical and mechanical properties of the reinforced plywood were determined using various tests. The results of the testing indicated that the plywood that was reinforced with woven glass fiber had a significantly increased modulus of rapture and modulus of elasticity of perpendicular samples. It was determined that density of the plywood was increased in the test groups. Thickness swelling and water absorption decreased for the test groups in which the plywood samples had woven glass fibers bonded onto in their surfaces. In the bending tests, the reinforcement provided by the glass fiber fabric decreased the inequalities between the parallel and perpendicular samples.

Enhanced interfacial adhesion of polypropylene and waste wood from roadside trees composite materials

In this study, increases in the moldability and interfacial adhesion strength according to the compatibility of different thermoplastic polypropylene polymer resin materials utilizing wood by-products produced by roadside tree pruning and changes in mechanical properties (impact strength ASTM D-256, tensile strength ASTM D-638, flexural modulus ASTM D-790) were verified. This study suggests the potential commercialization of wood composite materials from roadside tree pruning by-products of Platanus occidentalis L. based on compatibilizer treatment and the application of alkali and a silane coupling process. A new eco-friendly product group market is anticipated for use of this wood waste by-product, to reduce the use of limited petroleum resources, and to utilize ecofriendly cyclic-type resources.

Comparison of resistance improvement to fungal growth on green and conventional building materials by nano-metal impregnation

This study is aimed for comparing the biological resistance of green and conventional building materials (BMs) before and after nano-metal treatment, as well as exploring best nano-metals to improve fungal growth resistance of BMs. The selected BMs include wooden flooring (WF), green wooden flooring (GWF), gypsum board (GB), green gypsum board (GGB), calcium silicate board (CSB), green calcium silicate board (GCSB), mineral fiber ceiling (MFC) and green mineral fiber ceiling (GMFC). The Aspergillus brasiliensis or Penicillium funiculosum was inoculated on each sample and their growth was visually evaluated according to ASTM G21-09.The fungal growth without nano-metals on test materials did not show that green materials were more prone to fungal growth. After nano-metal treatment, the observed order of fungal growth resistance of nano-metals at their highest selected concentrations on test materials was nano-zinc = nano-copper > nano-silver for WF and GWF, nano-zinc > nano-silver = nano-copper for GB, nano-zinc > nano-silver > nano-copper for GGB, CSB and GCSB, nano-silver > nano-copper = nano-zinc for MFC, and nano-silver > nano-copper > nano-zinc for GMFC. Nano-zinc seems to be the most favorable nano-metal for wood and wood composite materials. Green materials were less resistant to fungi attack relative to their conventional counterparts treated by nano-metals, particularly GWF and WF. All test nano-metals failed to provide complete protection against fungal growth on the eight test BMs at the selected concentrations. However, the higher the nano-metal concentration was, the longer the lag period until growth began and fewer fungi grew on the materials.

Specific Modulus and Density Profile as Characterization Criteria of Prefabricated Wood Composite Materials

Wood based product industry has developed and modified a wide range of products to cater changing demands of construction industry. Development of a product necessitates characterization to ensure compliance to established standards. Traditionally a product was characterized by properties like bending properties, density and swelling factor etc. Whereas, advances in technology has introduced more sophisticated parameters which represent a combination of various classical factors and provide more practical and detailed information. In this study, we procured four different types of commercial products, viz. Gypsum board, cement board, oriented strand board and gypsum fiber board and tried to characterized them using density profile ratio and stiffness ratio. We observed some interesting empirical relations between various parameters as represented in various plots.

Vztah geometrie profilu lomové plochy a rázové houževnatosti kompozitních materiálů na bázi dřeva

The aim of this work is description of geometry of fracture surfaces of wood composite materials (cement-bonded particleboard, gypsum-bonded fibreboard and wood particleboard) using fractal analysis and exploration relation between fractal dimension and impact work. Fractal dimension determinated by filtration, volumetric and robust Box-Counting methods and Richardson method is different considering type of material and method. Proportional relationship between fractal dimension (computed by robust BC method) and impact work of mentioned materials was found in other cases non-proportional relationships were founded.

Basic Approaches to Green Production of Board Wood Composite Materials

Deep processing of wood raw materials is the main field of its use. The forecast of timber industry development provides deep chemical processing and start-up of board materials production. In the available forest reserves the share of pulpwood and forestry engineering raw materials is up to 13 per cent. Some measures will contribute to settle the problems of increasing wood raw material complex use and green production of board wood composite materials. They include the improvement of existing technologies and implementation of progressive technologies and systems increasing the volume and quality of board output. One of the main directions will be the maximum possible use of all components of raw materials, when some production wastes are the raw material for the manufacture of new products. This will provide the balance in efficient environmental management. The priority will be given to creation of a relatively closed cycle of wood resources use. Particularly promising in achieving a balance of economic and environmental interests of society will be obtaining of cheap boards capable to be not worse than solid wood with minimum cost of natural resources and preservation of individual properties of each component.

Effects of nanowollastonite on biological resistance of medium-density fiberboard against Antrodia vaillantii

The effect of wollastonite nanofibers (NW) on biological resistance of medium-density fiberboards (MDF) made from wood and chicken-feather fibers (CF) against Antrodia vaillantii was studied. NW content of 10 % and CF content of 5 and 10 %, based on the dry weight of wood fibers, were applied to the MDF matrix, giving a total of six different MDF mixing treatments. Mass loss values were measured roughly following the EN 113 specifications. The results showed that NW significantly decreased mass loss to a considerable extent in all mixing ratios, proving its potential to be used as a suitable preservative in wood-composite materials without environmental hazards. A CF content of 5 % showed improving effects on biological resistance, while CF of 10 % was too high and resulted in a weak MDF-matrix; eventually the biological resistance did not improve properly. NW ameliorated part of the undesirable effect of adding chicken feather fibers to the MDF-matrix. A significantly high correlation was found between mass loss versus water absorption (R2 of 81 %), implying that the penetration of water and fungal hyphae can have rather similar patterns. It can be concluded that NW not only can be used to improve the biological resistance in wood-composite materials against fungi attack, but it can also reduce some of the undesirable properties of chicken feathers, thus providing a reliable and renewable resource for natural fibers to be used in the MDF manufacturing industry.

Интерполяционный метод исследования процесса водопоглощения высоконаполненных древесно-полимерных композиционных материалов

Интерполяционный метод исследования процесса водопоглощения высоконаполненных древесно-полимерных композиционных материалов

Effects of nanowollastonite on biological resistance of particleboard made from wood chips and chicken feather against Antrodia vaillantii

The effect of wollastonite nanofibers (NW) on biological resistance of particleboard, made from wood chips and chicken-feather fibers (CF), against Antrodia vaillantii was studied. 10% of NW, as well as 5 and 10% of CF, were applied to the particleboard-matrix based on the dry weight of wood chips. Then, as a complimentary study, 10% wood fibers were also added to the wood chips; totaling, 10 mixing treatments. Specimens were prepared and mass loss (ML) values were measured in accordance with the EN 113 specifications. Results indicated that the highest ML (37%) occurred in the control treatment without NW- or CF-content; the lowest ML was seen in panels with 10% of NW, CF, and wood fibers (2.5%). NW substantially decreased ML in all mixing ratios. CF also showed a significant decreasing effect on ML. No significant correlation was found between ML values with any of physical and mechanical properties; however, high significant correlations were found between most of the mechanical properties. It is concluded that NW may be considered an effective filler in wood-composite industry to increase the durability against fungal attack; however, more studies should first be conducted on different fungi and wood and wood-composite materials to finalize this conclusion.

Древесные композиционные материалы с использованием соломы: проблемы и перспективы производства

Древесные композиционные материалы с использованием соломы: проблемы и перспективы производства

Оценка количественного состава природных полимерных связующих при производстве древесных композитных материалов и пеллет

Оценка количественного состава природных полимерных связующих при производстве древесных композитных материалов и пеллет

Формирование древеснокомпозиционных материалов из отходов деревообработки

Формирование древеснокомпозиционных материалов из отходов деревообработки

Wood specific gravity variation among five important hardwood species of Kashmir Himalaya.

Wood Specific Gravity (SG) is a measure of the amount of structural material a tree species allocates to support and strength. In the present study, specific gravity varied among the five different woods at three different sites from 0.40 in Populus nigra at site III (Shopian) to 0.80 in Parrotiopsis jacquemontiana at site II (Surasyar). Among the three different sites, specific gravity varied from 0.73 to 0.80 in Parroptiosis jacquemontiana; in Robinia pseudoacacia it varied from 0.71 to 0.79; in Salix alba, it varied from 0.42 to 0.48; In Populus nigra it varied from 0.40 to 0.48 and in Juglans regia it varied from 0.59 to 0.66. On the basis of the specific gravity variation patterns these woods were categorized as light (Salix alba, Populus nigra) moderately heavy (Juglans regia) and moderately heavy to heavy (Robinia pseudoacacia, Parrotiopsis jacquemontiana) which predicts their properties like strength, dimensional stability with moisture content change, ability to retain paint, fiber yield per unit volume, suitability for making particleboard and related wood composite materials and suitability as a raw material for making paper.

The “Schinkel’s Legacy” Project at the Kupferstichkabinett Berlin

AbstractIn the Kupferstichkabinett (Museum of Prints and Drawings) of the Staatliche Museen zu Berlin (National Museums in Berlin), the collection of the drawings and prints of Karl Friedrich Schinkel (1781–1841) is stored in cabinets made of laminated chipboard panels. The works are enclosed in portfolios that sit inside the cabinets on shelves made of bonded beech wood. Oddy tests carried out on the various storage materials showed their high corrosive potential on lead. In particular, the two wood composite materials caused a corrosion rate that was even higher than that of 5% acetic acid or 5% formic acid. The analysis of the air composition inside the storage cabinets confirmed this showing a considerably high concentration of acetic acid (4.7 mg/m