caa a22 4500 378867725 CHVBK 20180305123402.0 cr unu---uuuuu 161128e20030820xx s 000 0 eng 10.1515/HF.2003.080 doi (NATIONALLICENCE)gruyter-10.1515/HF.2003.080 Effect of High Temperature on the Change in Color, Dimensional Stability and Mechanical Properties of Spruce Wood [Elektronische Daten] [P. Bekhta, P. Niemz] In this study the effect of high temperature on mechanical properties, dimensional stability and color of spruce was investigated. Wood specimens conditioned at different relative humidities (50, 65, 80 and 95%) were subjected to heat treatment at 200°C for 2, 4, 8, 10 and 24 h and at 100, 150 and 200°C for 24 h. Color changes were measured in the Minolta Croma-Meter CR-300 color system. Bending strength and modulus of elasticity were determined according to DIN 52186. The results show that heat treatment mainly resulted in a darkening of wood tissues, improvement of the dimensional stability of wood and reduction of its mechanical properties. The darkening accelerated generally when treatment temperature exceeded approximately 200°C. Most of the darkening occurred within the first 4 h of exposure. For the specimens heated to high temperatures, the average decrease in bending strength was about 44-50%, while modulus of elasticity was reduced by only 4-9%. We found that treatment time and temperature were more important than relative humidity regarding the color responses. Strong correlations between total color difference and both modulus of elasticity and bending strength were found. Thus, the color parameters can be estimated quantitatively and used as a prediction of wood strength. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Timber & wood processing nationallicence Biotechnology nationallicence Materials science nationallicence Bekhta P. aut Niemz P. aut Holzforschung Walter de Gruyter 57/5(2003-08-20), 539-546 0018-3830 57:5<539 2003 57 hfsg https://doi.org/10.1515/HF.2003.080 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/HF.2003.080 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bekhta P. aut NATIONALLICENCE 700 1- Niemz P. aut NATIONALLICENCE 773 0- Holzforschung Walter de Gruyter 57/5(2003-08-20), 539-546 0018-3830 57:5<539 2003 57 hfsg CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter