Duchesne I.,FPInnovations Forintek Division |
Duchesne I.,Laval University
Wood and Fiber Science | Year: 2010
Color variations in paper birch wood were examined in boards sawn from sawlogs from 168 trees harvested from two different stands. Approximately 2250 boards were sawn from the logs. The within-tree variability was considered by looking at the effect of log quality and log height class on board color. Results show that neither the log quality nor the log height class had a significant effect on the proportion of discolored wood on the surface of the board. However, these log parameters had an effect on the wood colorimetric variables. Log position in the tree was found to significantly influence sapwood yellowness as well as discolored wood luminosity and redness. Log quality on the other hand significantly influenced only one colorimetric factor, sapwood redness. © 2010 by the Society of Wood Science and Technology.
Jin J.,Nanjing Forestry University |
Dai C.,FPInnovations Forintek Division
Forest Products Journal | Year: 2010
To characterize the variation in bending modulus of elasticity (MOE) and modulus of rupture (MOR), two commercial oriented Strandboard (OSB) products were selected. Master panels from multiopening, large hot presses were cut into standard panels of 1,220 by 2,440 mm, and then a total of 3,420 bending specimens were prepared in a continuous order and tested. The variations in bending properties were compared in terms of coefficient of variation (CV) and property differences both between and within master panels. The differences were evaluated by conducting analysis of variance and least significant difference tests. The correlation between MOE and MOR was also investigated. The results showed that the thicker OSB had less variation in bending properties than the thinner product. The variation of MOE (CV = 12% to 16%) was lower than that of MOR (CV = 20% to 22%). Although no significant differences were found in bending MOE and MOR between master panels, significant variations were noted in MOE and MOR within master panels. The differences in MOE and MOR between standard panels varied from 4 to 11 percent, and those along and across the forming line could vary from 8 to 17 percent and from 33 to 59 percent, respectively. The results suggest that product uniformity needs to be improved both along and across the forming line to lower production cost and improve product performance. The relationship between MOE and MOR was linear, with R 2 around 0.7. © Forest Products Society 2010.
Pan M.,Nanjing Forestry University |
Zhang S.Y.,FPInnovations Forintek Division |
Zhou D.,Nanjing Forestry University
Journal of Composite Materials | Year: 2010
Composites made of polypropylene (PP) and wheat straw fiber treated by alkalization, acetylation, and maleic anhydride polypropylene (MAPP) were prepared, and the dynamic mechanical, thermal, and rheological properties of the treated composites have been investigated. The PP composites reinforced with the treated wheat straw fiber exhibited higher brittleness. The melt flow studies were carried out at the temperature of 170, 180, and 190°C and shear rate of 0.01-0.1 s-1. The PP composites reinforced with the alkalized wheat straw fiber showed the high melt viscosity due to the strong chemical interaction among polymer and wheat straw fiber. The introduction of MAPP to the system increased the flow behavior of the polymer dispersed the wheat straw fiber uniformly, and decreased the melt viscosity. The PP composites introduced by 2wt% MAPP showed the lowest storage flexural modulus (E0) over the entire temperature range from 25-150°C, due to better compatibility between the wheat straw fiber and matrix. The PP composites made of with 20wt% alkalized and MAPP treated wheat straw fiber showed the highest E0. The differential scanning calorimeter (DSC) study revealed that introducing the wheat straw fiber to PP matrix increased the melting temperature and crystallization temperature. The PP composites reinforced with the alkalized and MAPP treated fiber had the highest rate of crystallization as a consequent of the co-effect of alkalization and esterfication. © The Author(s), 2010.
Peng L.,Carleton University |
Hadjisophocleus G.,Carleton University |
Mehaffey J.,FPInnovations Forintek Division |
Mohammad M.,FPInnovations Forintek Division
Fire Technology | Year: 2011
This paper presents an investigation on the fire performance of wood-steel-wood timber connections with slotted-in steel plates. In the first part, a three-dimensional thermal model was employed that uses the finite element method to analyze heat transfer within timber connections exposed to the standard fire. The temperature-related properties were obtained from the literature and imported into the thermal model. A validation of the proposed thermal model was achieved by comparing predicted temperatures with experimental results. In the next phase, a reduction in the embedding strength method was adopted to estimate the load-carrying capacity of connections in fire. Based on the temperature profiles within the connection calculated by the thermal model, the reduction of the embedding strength was determined and used to calculate the load capacity at elevated temperatures. Furthermore, a formula was proposed to evaluate the fire resistance rating of timber connections and compared with the results of fire resistance tests. The parameters considered included the load level, fastener diameter and wood member thickness. © 2009 Springer Science+Business Media, LLC.
Li Y.F.,Northeast Forestry University |
Liu Y.X.,Northeast Forestry University |
Fu Y.L.,Guangxi University |
Wu Q.L.,Louisiana State University |
Wang X.M.,FPInnovations Forintek Division
Materials Science Forum | Year: 2011
Bio-based materials such as wood, bamboo, bio-straw material are vulnerable to degradation by microorganisms and susceptible to change in dimension under humidity, which greatly reduced their service life. In this study, a novel thought was inspired from the unique porous structure of bio-based material that durability of wood may be capable of being improved by generating polymer in situ the special structure. Maleic anhydride (Man) and Styrene (St) were used to penetrate into wood for further copolymerization. SEM observation shows that polymer filled in wood porous structure and tightly contacted wood matrix (i.e. biopolymers), indicating strong interaction between them. FTIR analysis indicates that polymer chemically grafted onto wood matrix by reaction of anhydride group and hydroxyl group. As the amount of hydroxyl groups greatly reduced for their reacting with polymer, the dimensional stability of wood immersing in water was improved; and as the reaction of wood with polymer, the biopolymers were wrapped by resultant polymer, preventing the sample from attack of microorganisms, thus decay resistance of treated wood against microorganisms was greatly improved. Both of them contributed to the improvement of wood durability. © (2011) Trans Tech Publications.
Han G.,Northeast Forestry University |
Deng J.,FPInnovations Forintek Division |
Zhang S.,665 East Mall |
Bicho P.,800 Wesbrook Mall |
Wu Q.,Louisiana State University
Industrial Crops and Products | Year: 2010
Steam explosion treatments were used to modify straw fiber attributes for panel manufacturing. In particular, the effect of steam temperature and retention time on morphology, acidity, wettability, and ash and silicon contents of wheat straw was studied. After steam explosion treatments, proportion of large particles decreased, while fiber bundles increased. Higher steam temperature and longer retention time resulted in more homogeneous fiber-like material. The results showed that the pH value of the untreated wheat straw fiber was nearly 7 and the pH values and acid buffer capacities of straw were greatly reduced after steam explosion treatments. This indicated that the acidity of straw increased after steam explosion treatments. The dynamic contact angle of the straw before the treatment was nearly 90°, indicating that the straw material without treatment is more hydrophobic. After steam explosion treatments, the contact angle of straw was significantly reduced, showing that the surface wettability of the treated straw was improved. The ash and silicon contents of straw were also significantly reduced by steam explosion treatments. The improved acidity and wettabillity as well as decreased silicon content would contribute to the improved bondability between straw particles and water-soluble adhesive binders. © 2009 Elsevier B.V. All rights reserved.
Zhao J.,China Academy of Building Research |
Wang X.-M.,FPInnovations Forintek Division |
Chang J.M.,Beijing Forestry University |
Yao Y.,China Academy of Building Research |
Cui Q.,China Academy of Building Research
Composites Science and Technology | Year: 2010
The sound insulation property of wood/used tire rubber composite panel (WRCP) was investigated. A four-microphone method was used to measure the sound transmission losses of three different composite panels: WRCP, commercial compound wooden floorboard and commercial wood-based particleboard. The WRCP was manufactured in the lab with commercial urea-formaldehyde (UF) and polymeric methylene diphenyl diisocyanate (PMDI) adhesives. The test results indicated that sound insulation property of WRCP is better than that of commercial compound wooden floorboard and wood-based particleboard. In addition, the acoustic insulation of WRCP is significantly affected by the amount of rubber crumbs and PMDI adhesive used in the composite. An increase in the usage of recycled tire rubber crumbs and the dosage of PMDI adhesive significantly improve the soundproof property of the WRCP. Moreover, the microstructure of WRCP was examined using a scanning electron microscope (SEM). The sound insulation effect is also dependant on the microstructure of the interface zone of wood/rubber and densification of WRCP. The continuous interfaces are formed in the presence of sufficient UF and PMDI adhesives resulted in better soundproof WRCP. © 2010 Elsevier Ltd.
Li Y.,Northeast Forestry University |
Liu Y.,Northeast Forestry University |
Wang F.,Northeast Forestry University |
Wang X.,FPInnovations Forintek Division
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2010
In order to prepare a polymer reinforced wood-based composite with excellent properties, a fast-growing wood, Populus ussuriensis Kom, and glycidyl methacrylate (GMA) as a difunctional monomer and methyl methacrylate (MMA) as an acrylate monomer were selected, and the monomers were impregnated into the porous structure of wood and further initiated by a catalyst-thermal treatment for their in situ polymerization. The composite's structure was characterized by SEM, FTIR and XRD, and its corresponding properties were also tested. The results show that the contact between polymers and wood cell walls is tight, and the interfacial interaction is strengthened after adding GMA. GMA fully reacts with the hydroxyl group on wood cell walls by its epoxy group, and reacts with MMA in a free radical copolymerization form by its double bond. The copolymer, P(GMA-co-MMA) is finally grafted onto wood cell walls in an amorphous form. The testing results of its properties show that the modulus of rupture (MOR), the dimensional stability, the decay resistance and the thermal stability of P(GMA-co-MMA)/wood are increased by 90.53%, 54.05%, 92.85% and 31°C compared with those of untreated wood, respectively.
Nybakk E.,Norwegian Forest And Landscape Institute |
Crespell P.,FPInnovations Forintek Division |
Hansen E.,Oregon State University
Silva Fennica | Year: 2011
This study examines the relationships between firm financial performance and a) the climate for innovation and b) innovation strategy in the wood products industry. The focus is on the moderator effects of firm size, country of operation, and industry sector. Using a sample of 460 responses from chief executive officers and top managers of Norwegian and US firms, we conducted a regression analysis to probe for interaction effects. The sample included primary and secondary manufacturers of various sizes. Consistent with previous studies, we found a positive impact for both a climate for innovation and an innovation strategy on firm performance. In terms of moderation, only one interaction was found to be significant, representing a moderator effect of industry × size on the climate-performance relationship. Further testing showed that secondary, large manufacturers exhibited a weaker, yet still positive, relationship between climate for innovation and performance. This low level of significant interactions suggests stability of the relationship among the main factors depicted in the model, with important implications for managers and future research. These findings indicate that a positive climate for innovation and a management committed to innovation through an innovation strategy have a positive effect on the bottom line of wood products firms. This effect holds true regardless of industry, size, or country, so most firms can benefit from the implementation of these pro-innovation practices.
Liu Z.-M.,Northeast Forestry University |
Daniels C.R.,FPInnovations Forintek Division |
Morris P.I.,FPInnovations Forintek Division
Journal of Wood Chemistry and Technology | Year: 2010
Western red cedar (WRC) (Thuja plicata Donn.) is one of the most durable softwoods in North America, and this durability has largely been attributed to its tropolone content. Further studies on factors contributing to the durability of this species require isolation of substantial quantities of the active components. Wood meal from the heartwood butt of a WRC tree was extracted with hexane for 24 hours. The thujaplicin mixture was obtained by chloroform extraction of the alkali solution adjusted to a pH of 6.5. With chemical conversion and regeneration, the selected compound, gamma-thujaplicin, was isolated from the thujaplicin mixture and characterized by Fourier transform infra-red (FTIR) spectroscopy, High Performance Liquid Chromatography (HPLC), Mass Spectroscopy (MS), 1H-nuclear magnetic resonance (NMR), Gas Chromatography-Mass Spectroscopy (GC-MS), a color test, and comparison with standard gamma-thujaplicin. Relative purity reached up to 99%. Additionally, a by-product, nezukone, could be also isolated from the hexane extractives. Copyright © Taylor & Francis Group, LLC.