Showing papers in "China Wood Industry in 2005"

Physical and Mechanical Properties of Glued Structural Laminated Bamboo

Abstract: The physical and mechanical properties of structural glued laminated bamboo were studied and compared with LVL made from several kinds of plantation wood, as well as common structural solid wood. The result showed that the glued laminated bamboo exhibited excellent properties on horizontal shear strength, MOR and MOE, but the poor performance in an aging test.

Study on Properties of Steel/Wood Fiber Composite MDF

Abstract: The ratio of steel fiber and wood fiber in a composite MDF, which could be used as electromagnetic shielding material, was studied in this paper. The results showed that steel fiber mixed with wood fiber can cause a negative effect on bonding strength of the composite MDF board, but a certain amount of PMDI resin applied on the steel fiber can significantly improve the board properties. The steel/wood fiber ratio and the mixed fiber position in the MDF also showed an effect on the electromagnetic shielding property of the board. The composite MDF had good electromagnetic shielding effectiveness with values beyond 55 dB at a steel/wood fiber ratio of 3∶1 and the steel/wood composites on the top and bottom surfaces of the MDF.

Profile Density Measurement for Wood Based Panel Quality Control

Abstract: Since the profile density of a board will directly affect its physical and mechanical (performances) as well as the total production cost for a wood-based panel factory, an accurate (measurement) of profile density is necessary to make products with higher quality and lower cost. (Technical) factors that may cause ill-proportioned density distribution in boards were analyzed. The authors (also) made some suggestions on how to adjust technical parameters based on the test results.

The Relationship between the Wood Industry and SustainableForestry Development in China

Abstract: Developing China's wood industry can have many advantages for China. First of all, it will help improve the efficiency of wood utilization and save forest resources. It will also better( utilize) small diameter trees and forest residues for value-added products, use non-wood material( (agricultural fibers)) for composite products manufacturing to reduce the demand for wood fibers, (develop) new technology for using young plantation materials to replace logs from virgin forests, (promote) tree planting activities at the national level, improve the environment, reduce green-house (effects) and provide funds for sustainable forestry development. If some or all of these suggestions (are implemented), it would advance the development of the wood industry and promote sustainable development of forestry in China.

Wood Defect Recognition in Log CT Images by Artificial Neural Network

Abstract: This paper introduces a method for automatic analysis of wood defects in CT images through artificial neural networks (ANN) Experiments on European ash (Fraxinus excelsior) showed that the ANN of nodes in different hidden layers could accurately distinguish wood bark, knot, decay and clear logs, but it did not work well for fine splits The application of the method is helpful to realize quick and automatic recognition of wood defects, and to draw an optimal sawing scheme

Dyeing Technology of Poplar Veneer with Reactive Dyes

Abstract: Dye technology for Poplar (Populus yunnanensis) veneer was conducted to imitate Walnut (Juglans nigra) wood. Red, yellow and blue reactive dyestuffs were selected. Results showed that the dyeing effect could be dominated by controlling the dyeing temperature and time, as well as the dosage of the accelerating agent and the color fixing agent. A satisfactory effect could be obtained under the following dyeing conditions: a temperature between 70~80 , a time of 3 h using Na_2SO_410H_2O as an accelerating agent at a concentration of 40 g/L,and Na_2CO_3 as a color fixing agent at 20 g/L.

Processing Technology of Strengthened Bamboo/Wood Composite LVL

Abstract: Strengthened bamboo/wood composite laminated veneer lumber (LVL) was manufactured using poplar (Populus nigra) veneer and bamboo curtains as raw materials, impregnated with modified water-soluble PF resin. The effects of the impregnating process, assembly patterns, and hot pressing parameters on properties of the bamboo/wood composite LVL were explored. The results showed that MOE and MOR of the composite LVL could meet or surpass the relevant requirements of JAS standards. They also exhibited rather desirable dimensional stability with TS 2.4%. Veneer thickness, PF resin concentration, as well as compression ratio, all had significant influences on MOE and MOR. Assembly patterns were found to have a major effect on MOR. Furthermore, there were complicated factors associated with TS of the composite.

Study on Mixing Conditions for Polypropylene and Wood Fiber

Abstract: The composites investigated in this paper were made from wood fibers either with (polypropylene) only, or with polypropylene modified with maleic anhydride or alternatively coupled with a silane agent. The adhesion between wood fiber and polypropylene was evaluated (through) (testing) the tensile strength of the composite. An analysis was made on how the tensile strength was influenced by the ratio of wood fiber to polypropylene, as well as the effect of the addition of maleic anhydride and the silane coupling agent to polypropylene. It was found that when the polypropylene and wood fiber was mixed at 10∶3 and 3%～5% coupling agent was added to polypropylene, the wood-polypropylene composite showed the best tensile strength.

Influence of Testing Condition on Thickness Swelling Rate for Wood-based Panels

Abstract: The influence of a constant temperature and humidity treatment, as well as soaking temperature on thickness swelling (TS) rates for wood-based panels, was investigated in this paper. The results showed that, for medium density fiberboard (MDF) and particleboard, their thickness swelling rates increased when the soaking temperature was increased, and there was a linear relationship between them, whereas, plywood was influenced little by the soaking temperature. Also studied was whether treating the specimens in a constant temperature and humidity condition before soaking would influence TS test results. It was also found to be essential to give a conditioning treatment for particleboard and thin MDF to ensure correct test results.

Current Markets and Potential Applications for Agri-fiber Based Panels in China

Abstract: The current development and existing problems in the agri-fiber based panel industry are presented in this paper. As a useful, recyclable raw material resource, the technical feasibility and application potential of wheat/rice straw boards are analyzed.

Radio Frequency/Vacuum Drying Technology on Plantation Grown Chinese Fir

Abstract: A series of radio frequency/vacuum(RF/V) drying tests were conducted using plantation grown Chinese Fir(Cunninghamia lanceolata)with thicknesses of 25 mm and 50 mm.Results showed that the dried lumber had good drying qualities with little distortions and low final moisture content gradients.Although the initial moisture content of samples was quite diverse,if the samples were sorted by initial moisture content and stacked from negative electrode to positive electrode according to the initial moisture content from low to high,an even final moisture content distribution could be obtained throughout the stack.

Research Advances on the Interfacial Compatibilization of Wood/Plastic Composites

Abstract: Wood/Plastic Composites is a newly developed material and can be used in many fields Since the interfacial compatibility is one of the key factors in the production and application of wood/plastic composites, the current advances on interfacial compatibilization are reviewed in this paper This research covered both domestic and foreign literature With the focus on industrial application, the authors stress that adding compatibilizers in the compounding phase will be more effective than chemical modification on the polarity of a wood surface to improve the interfacial compatibility between the wood and plastic The authors also point out that further research should focus on developing equipment suitable to normal production of wood based panels, and various compatibilizers that adapt to different species of wood and other lignocellulosic materiales, and plastics under high moisture content condition

Trends of the Wood Based Panel Industry

Abstract: Wood-based panels combine the economic and ecological benefits of the renewable wood resource with the tailored properties of a modern composite. After reviewing the present status and prospect of the wood based panel industry thoughout the world, the author suggests that in (response) to the economic globalization and China's entry into the WTO, the Chinese wood based panels industry should follow the sustainable development principle, better understand the forest, improve the management of operations, recycle more and pollute less, make better use of the forest resources so as to enhance its international competitiveness to supply customers better products and services at lower cost.

Preparation and Characterization of Liquefied Wood in Presence of Phenol under Acid Catalysis

Abstract: The experiments of Poplar (Populus×euramericana cv.‘I-214’) and Chinese Fir(Cunninghamia lanceolata) wood flour liquefied in the presence of phenol under sulfuric acid catalysis were conducted. The effects of reaction time and reaction temperature on the wood liquefaction were investigated. By means of gel permeation chromatography(GPC) analysis, the molecular weights of liquefied wood under different reaction conditions were measured to trace the change in the structural characteristics of the liquefied wood. The insoluble residues were analyzed by Fourier transform infrared to investigate the liquefaction order of three main wood components. The results showed that 1) the liquefaction curves for the Chinese Fir and Poplar were similar in general. The acidic catalyst showed a function not only on cellulose and hemicellulose, but also on lignin. 2) The reaction temperature had the greater influence on the residue content than reaction time. Both reaction temperature and reaction time could affect the molecular characteristics of liquefied wood. The weight-average molecular weight of liquefied Chinese Fir was higher than that of liquefied Poplar under most of the reaction conditions. 3) During wood liquefaction, lignin and hemicellulose were liquefied first and cellulose being the most difficult to liquefy. The decomposition, phenolation and recondensation of wood components are three main reactions which dominated the whole liquefaction dynamic process and determined the structural characteristics of liquefied wood.

Effect of Test Methods on Plywood Formaldehyde Emission Content

Abstract: The effects of edge treatment, sampling location, and moisture content of plywood specimen on its formaldehyde emission were discussed. Results found that: 1) Formaldehyde emission content of a plywood board was closely related to the end-edge area of the specimen, while it changed little whether the surface of the specimen was covered or not. 2) Test specimens from a same board at different locations had slight difference in formaldehyde emission. The specimens in the middle or margins locations had more formaldehyde emission than those at the other locations. 3) The moisture content of a specimen had a remarkable effect on the formaldehyde emission (content.) In a relatively low degree, the formaldehyde emission content of a specimen increased with the (increast) of its moisture content.

Manufacturing Technology of LVL from Paulownia with UF Resin

Abstract: Following a series of experiments that had verified the feasibility of manufacturing (laminated) veneer lumber from Paulownia (Paulownia elongate) with urea-formaldehyde resin, the (authors) arranged an orthogonal experiment to determine the optimum technology parameters. (Results) showed that under the conditions of hot pressing at a temperature of 130 ℃, hot pressing time for (1.4) min/mm and glue spread of 380 g/m~2, all the physical and mechanical properties of the Paulownia LVL samples could satisfy the requirements for indoors materials.

Applications of Dynamic Mechanical Analysis in Wood Processing Industry

Abstract: This paper presents the principle of dynamic mechanical analysis (DMA) method, which could be used to examine and evaluate mechanical performance of wood-based materials. It also discusses some specific uses of DMA in the wood processing industry.

Research Status and Developing Trends in Wood Dyeing Technology

Abstract: With the rapidly increasing demand for indoor decorative wood and the explosion of the furniture manufacturing industry in China,the process and technology of the wood dyeing industry has also undergone dramatic changesThis paper reviews the history,and then focuses on current research and the application of wood dyeing techniques,both in China and abroadA look at future research and possible development trends for wood dyeing are then presented

Gray Morphology Filtering for Wood Defect Images

Abstract: This paper first defined gray morphology filtering methods based on mathematical morphology, followed with examples of a wood defect image treated before and after open, as well as closed, filtering treatments. By observing the sectional gray distribution of the wood defect image, the effects of the filtering treatments were determined. Results found that gray morphology filtering could effectively remove noise in wood defect images, improve image vision and heighten accuracy for edge detection. The results verified the feasibility of applying gray morphology filtering to treat wood defect images.

Review of Research Methods for Wood Drying Stresses

Abstract: Studies on wood drying stresses are very helpful to further the science of wood drying, establish suitable kiln schedules and improve the quality and economics of the wood drying process. Many scientists have studied different aspects in the field of drying stresses and developed numerical calculations for their results. This paper reviewed and summarized the typical study methods and made some comments and suggestions for further studies.

Application and Production Techniques of Honeycomb Panels Used in Wooden Pallets

Abstract: With China experiencing a serious shortage of wood resources,the use of substitute wood packaging materials is becoming an urgent problem.Honeycomb panels are one solution to the problem due to their light weight,recyclability,and good resistances to crushing and earthquake.This article starts with reviewing the current materials that are used in the packaging industry around the world.It then analyzes the structure and physical properties of honeycomb pallets and demonstrates the feasibility and technology for making pallets with honeycomb panels.Finally,it suggests some rational ideas for solving production problems.

A Study of the Properties of Three Different Wood Fiber-Plastic Composites

Abstract: Three kinds of plastics, linear low-density polyethylene(LLDPE), polypropylene(PP) and polystyrene(PS), were chosen to prepare the wood/plastic composites at two proportions of 25︰75 and 40∶60. The effects of different plastics on the properties of the wood fiber-plastic composites are evaluated though testing and comparing physical and mechanical properties. The results indicated that the compounding property of LLDPE with wood fiber was the best and its composite also showed good impact resistance, but its flexural strength and modulus were the lowest. For the wood fiber-PS composite, the flexural strength and modulus were excellent, but the impact resistance and the compounding property of PS with wood fiber were poor. On the whole, the properties of the wood fiber-PP composite were superior to the other two. Based on these results, the authors suggest that it is very necessity to develop blends of low-density polyethylene and polystyrene to be used for wood/plastic composites.