Study On Thermal Modification Of European Spruce

Based on documents and prior work, nine treating methods in which heat is used to European Spruce wood under the protection of high-pressuring N2 are used to find Out the optimum one for specific usage. The effects of primary factors on Thermowood and the properties of Thermowood are studied. The conclusions drawn according to experimental data are followed as: (1) All of treating temperature, treating time, wood moisture content and N2 pressure affect the properties of Thermowood, but the two of former are most sensitive to the properties and the wood moisture content is second. Nitrogen pressure affects least on Thermowood among these factors. (2) The density distribution is studied and the strength of peaks of wood cell wall fall little compared to untreated wood. The fall between early wood and late wood is different. The former is less than the latter; The color of Thermowood changes from oyster white of untreated wood to sandy beige. Lightness and hue angle are lower but chroma higher after thermo-treatment. Within the range of visible light, special between 430nm and 500nm, the reflectance of wavelength falls much; The dimension stability of Thermowood is improved remarkably. The Anti-Swell Efficiency (ASE) whether radial or tangential direction is up to 26.57%-52.31%; The mechanical properties fall by 6% to 30%. The mechanism of Thermowood is also probed by pH measurement and FTIR analysis.