International Wood Products Journal

Resin impregnated wood nails create an opportunity to use more renewable materials in place of metal fasteners, but there are few data on the effects of moisture cycling on performance. The properties of resin impregnated, compressed beech nails that had been subjected to repeated wetting and drying were compared with steel nails using radiata pine lumber. Sections cycled between ∼12 and ∼50% moisture content were destructively tested in shear. Capacity increased slightly with exposure to one moisture cycle for both connector types. Significant negative effects on wooden nail stiffness were only observed after 5 or 7 moisture cycles. Metal nails failed in a ductile fashion while the timber connectors failed in a brittle mode. The results suggest that wood fasteners can withstand some wetting, but repeated moisture cycling will be detrimental to performance.

This paper reports an in-depth comparative study on the effects of Trametes versicolor on sugar-cane residue polypropylene composite and medium density fibre board. The samples were subjected to the fungus at 25°C and 75% relative humidity either for 2 or 4 months. Mass, bending strength, elastic modulus, hardness, and equilibrium moisture content (EMC) of both products reduced, while water absorption and thickness swelling increased due to biodegradation. The rates of mass, bending strength, elastic modulus, hardness, and EMC reductions, and water absorption and thickness swelling increases in MDFs were far higher than those of the composites, indicating the lesser susceptibility of the latter samples. Elastic modulus of the composites and hardness of MDFs were more adversely affected under fungal attack, whereas hardness underwent higher rates of reduction in the composites, as compared to the other properties. Scanning electron microscopy was conducted to characterise the alterations in mechanical properties.

The aim of this study was to evaluate the potential of colorimetry to characterize six species (Hymenolobium petraeum, Dipteryx odorata, Ormosia sp., Enterolobium maximum, Hymenaea courbaril e Pseudopiptadenia suaveolens) of the Fabaceae family. Wood samples were collected in extractivist communities in Pará state, Brazil. Colour data were obtained randomly on the three anatomical sections, along with reflectance spectra in the range of 360–740 nm. All analyses were carried out with RStudio. In general, reflectance spectra were similar for all species. However, for the Principal Component Analysis results, P. suaveolens stood out. The colorimetric parameters L*, b* and C*, in radial sections, are more important on colour results of the majority of wood samples. Colorimetry spectroscopy showed potential for characterizing some Fabaceae species. Therefore, the technique can serve as a support tool for better identification of this group, contributing to the reduction of ecological and socio-economic damage.

Small-diameter logs are intended to function as high-value structural timber. Bending strength properties is an essential phenomenon for structural lumber. Herein, the modulus of elasticity, the modulus of rupture and the allowable bending stress (ABS) of domestic (Korea) small and large-diameter larch and large diameter Douglas fir timber were measured and compared according to the standard of ASTM D 2915. Samples were visually graded as Grade 1 to Grade 4 following the provisions included in KS F 3021.2013. The large-diameter Douglas fir timber (Grade 1 to Grade 4) exhibited the highest MOE value, but in Grade 4, it showed the lowest MOR value compared with the small and large diameter of larch timber. The ABS of small-diameter larch was 12.0 MPa, higher relative to KBC 2009 Grade 1 structural lumber (8.0 MPa). The ABS of large-diameter of larch and Douglas fir timber exhibited 15.5 and 18.1 MPa, respectively.

The present environmental limitations and also the depletion of oil-based resources have resulted in greater thrust for the development of environmentally friendly and energy-saving biocomposites termed as green composites. The unique combined properties of biofibres have introduced this new class of biocomposites as a versatile alternative to the present petrochemical composite materials. Considerable efforts are now underway to effectively take advantage of the synergistic effects of combining natural reinforcements and plant-derived polymers for high-performance green composites and nanocomposites. This paper reports the most recent advances in characterization and multifunctional properties of different agro-waste fibres and polymers. The structural properties and functions of the resulting green composites along with their applications are also discussed in details in each section. The current research trends for modification of natural fibres, processing techniques of the given composites as well as their future prospects and challenges are addressed.

Acacia, an exotic fast-growing tree species was introduced into Southeast Asian countries on degraded soils. In Bangladesh, China, India, Vietnam, Indonesia plantations of Acacia were established for pulpwood production with people's participation. This paper reviews the current knowledge of the physical, chemical and morphological characteristics of A. auriculiformis and its pulping potential. The wood density, chemical and morphological properties of A. auriculiformis impacted positively for pulpwood selection in many countries. A. auriculiformis planted in a social forestry programme in Bangladesh and other countries showed almost similar characteristics to A. auriculiformis grown in different parts of the world. It is a promising species for pulping in Bangladesh and other Southeast Asian countries, at the same time poor people can improve their livelihood through participation in social forestry programme by planting this species.

The torsion test is recommended as a standard approach to determine the shear modulus of structural-size timber and glulam beams. However, there is difficulty in measuring the rotational deformations of timber beams. A stereo camera system and photogrammetric approach are therefore proposed in this study. This study evaluates the applicability of the proposed photogrammetric approach to the torsion testing method on solid timber beams. Tests were performed comparing rotational values of specific points determined by the photogrammetric approach with those measured by traditional devices. Remarkable findings were obtained which may help to develop an outline for future research in the field of evaluating material properties of timber beams. The results also showed that the optical system not only allowed the assessment of performance and reliability of traditional sensors, but also allowed monitoring the deformation of samples at various locations by providing more information which would be unobtainable using traditional techniques.

An innovative eco-friendly technology, applied to improve the quality of the short rotation teak, was wood modification by heat treatment. The study was to investigate the effects of heat treatment at 180°C, 200°C, and 220°C on the characteristics of the short rotation teak. The results show that the short rotation teak degraded hemicellulose and increased α-cellulose and lignin after the heat treatment. Anti-swelling efficiency value after heat treatment was improved ranging between 12.9% and 46.7%, indicating an improvement in dimensional stability. The MOE and MOR values decreased after heat treatment. The heat treated sample at 180°C after graveyard test was the lowest in weight loss, which presented good durability against termite (rating 9) and decay (rating 10). The surface roughness and SFE values decreased as the heating temperature increased. The heat treated at 220°C provided the lowest K-values (0.04 for acrylic and 5.04 for alkyd paint) which indicate the poorest wettability.