The effect of cryogenic treatment on some chemical, physical, and mechanical properties of Thermowood® Oriental spruce

Effects of cryogenic treatment on the chemical, physical, and mechanical properties of oriental spruce wood, which was heat-treated with the Thermowood® method, were investigated in this work. Cryogenic treatment, which is a secondary process applied to industrially heat-treated ferrous and non-ferrous metallic materials, was applied to Thermowood® Oriental spruce wood. For this purpose, Oriental spruce wood was first heat-treated at two different temperatures (190 and 212 °C), and then both Thermowood® and control samples were cryogenically treated at -80 °C. The effects on shrinkage and swelling pressure resistance parallel to fibers, and the elemental structure were examined. The findings revealed that the improvement in shrinkage and swelling continued with heat treatment, and there was an average increase of 18 and 14.5%, respectively, in the compressive strength parallel to fibers compared with control and heat-treated samples. The FT-IR analysis showed that the wood compound structure was mostly cellulosic. The difference between the carbon-oxygen ratio in the cryogenically-treated wood decreased compared to the percentage change in the three basic elements, and the amount of hydrogen increased proportionally.