Thermal modification of wood and a complex study of its properties by magnetic resonance and other methods

Abstract

International audienceThermal modification of wood is an effective method to improve some of the properties of wood. It is reported on studies of vacuum thermal-treated wood species by magnetic resonance methods. Wood species such as Scots pine (Pinus sylvestris), birch (Betula pendula), Russian larch (Larix sibirica), Norway spruce (Picea abies), small-leaved lime (Tilia cordata) were vacuum treated by heat at 220 °C with various durations up to 8 h. This selection of wood species was investigated by electron paramagnetic resonance, nuclear magnetic resonance and microscopy methods before and after the thermal treatment. Electron paramagnetic resonance experiments revealed changes in the amount of free radicals in samples with the thermal treatment duration. Additional information on magnetic relaxation of 1H nuclei in samples at room temperature was obtained. Optical microscope analysis helped to detect structural changes in the thermally modified wood. Important properties of wood such as wood hardness and humidity absorption were also studied. The original results that were obtained correlate and complement each other, and clarify changes in the wood structure that appear with the heat treatment

Determination of Kinetic Parameters of Thermodestruction and Groups of Fireproof Efficiency of Pine Wood, Modified by Boron Nitrogen Flame Retardant

“…Химическое модифицирование древесины широко используется для улучшения ее свойств [1,2]. Изменение химического состава и структуры поверхностного слоя древесины в результате привития молекул функциональных модификаторов приводит к увеличению био-и огнестойкости, повышает устойчивость древесины по отношению к воде и другим агрессивным средам, стабилизирует форму и размеры деревянных конструкций и изделий [3][4][5][6].…”

Influence of wood thermal modification on the supermolecular structure of polypropylene composites

“…The scale of changes depends on the conditions of the process and increases in higher temperatures. [26][27][28][29][30] Moreover, the water content in the wood decreases, thus increasing their hydrophobicity, improving dimensional stability, and increasing biological resistance. [28][29][30][31][32][33][34] The changes associated with the thermal treatment of wood also affect its supermolecular structure and change the crystallinity of cellulose.…”

Flammability characteristics of thermally modified oak wood treated with a fire retardant

“…It is responsible for the rigidity of the material and is the most resistant to heat of these three components (Cademartori et al 2013). TM improves the dimensional stability, durability, hygroscopicity, weather resistance, and resistance to fungi (Jämsä et al 2000;Candelier et al 2013;Kačíková et al 2013;Baysal et al 2014;Kondratyeva et al 2016). In contrast, TM, especially above 220 °C, noticeably reduces the mechanical properties, e.g.…”