Wood-Composite Boards with a Low Coefficient of Linear Thermal Expansion
Journal Title: Lesnoy Zhurnal (Russian Forestry Journal) - Year 2024, Vol 2, Issue 2
Abstract
A number of industries require materials with a low coefficient of linear thermal expansion (CLTE), in particular, in the production of satellite spherical antennas. The latter are formed from composites containing carbon fibers and synthetic resins. The composition is cured by heating up to 180 °C. This leads to a thermal expansion of the mold and a change in the geometric characteristics of the product. Therefore, specific requirements are imposed on the materials for making molds. The high cost of special materials used for molds determines the need to search for other materials with a low CLTE. Wood is a possible solution to this problem. Its CLTE along the fibers is less than that of the vast majority of materials, and is approximately 3 ⧠10-6 Kâ1, which is comparable to special materials. However, the expansion of wood across the fibers is much higher than the longitudinal one, which excludes the use of solid wood. Anisotropy can be reduced by creating a composite in which the fibers are uniformly oriented in all structural directions, bringing the value of wood expansion across the fibers closer to the value of expansion along the fibers. The traditional approach to producing wood composites, based on the use of synthetic adhesives, fails to achieve a noticeable reduction in thermal expansion due to the high CLTE of adhesives The use of boards made of hydrodynamically activated wood particles without binders is promising. Three series of experiments have been carried out: with varying the density of the boards, preliminary thermal modification of the original wood and the use of alkali during hydrodynamic processing. The thermal expansion study has been carried out using the NETZSCH DIL-402 C induction dilatometer in dynamic mode with a heating rate of 2 K/min. It has been established that thermal expansion increases with increasing density.The average CLTE at a density of 950 kg/m3 is 12 â§10â6 Kâ1 and at a density of 1,100 kg/m3 it is 17â§10â6 Kâ1. At a comparable density, the thermal expansion of boards without binders is significantly lower than that of fiberboards (MDF). Preliminary thermal modification of wood does not significantly affect the CLTE of the boards. The use of alkali in the hydrodynamic treatment also has no effect.
Authors and Affiliations
Vladimir N. Ermolin, Mikhail A. Bayandin, Alexey V. Namyatov, Nikolay V. Smertin
Keywords
Related Articles
- EP ID EP734360
- DOI 10.37482/0536-1036-2024-2-142-151
- Views 52
- Downloads 0
Typification of Forest Areas by Natural-Production Conditions Based on Cluster Analysis
The effectiveness of harvesting machines, their reliability, and the level of negative environmental impact depends on the degree of adaptation of the equipment to natural-production conditions (NPC). To choose the equip...
Cytogenetic Characteristics of Seed Progeny of Scots Pine Plus Tree Clones in Karelia
The article describes the cytogenetic parameters of seed progeny of Pinus sylvestris plus trees growing in the Petrozavodsk seed orchard of the first order. P. sylvestris normal trees from the natural pine phytocenosis i...
Navigation and Piloting System of Unmanned Aerial Vehicle for Forest Fire Monitoring
Forest fires are a common natural disaster all over the world. A great number of fires occur annually in the forest ecosystems of the European North of Russia for natural reasons and as a result of anthropogenic impacts....
Influence of Highly Active Compounds on Mechanical Properties of Wood of Two-Year-Old Scots Pine Seedlings in Forest Nurseries
Scots pine (Pinus sylvestris L.) has the leading environment-forming function. Also, the pine is an economically valuable tree species in the Ural region. The long-term use of the pesticide complex in forest nurseries ha...
Effect of Technical Aerosil on the Properties of Adhesive Compositions
The main drivers of competition among the products made with the use of adhesive compositions are the toxicity of finished products, the consumption of raw materials and energy resources, the duration of the main technol...