Performance Analysis of Loose-Fill Thermal Insulation from Wood Scobs Coated with Liquid Glass, Tung Oil, and Expandable Graphite Mixture

The current study presents the results of monitoring the behavior of loose-fill thermal insulating material for buildings made of wood scobs (WS), which were coated with one, two, and three component-based coatings from liquid glass (LG), tung oil (TO), and expandable graphite (EG). The thermal conductivity of samples in the dry state and under normal laboratory conditions, short-term water absorption by partial immersion, surface wettability, and water vapor permeability were evaluated, and regression equations describing the variations in numerical values of specified properties under different amounts of each coating component were presented. It was shown that LG and TO act as hydrophobic layers that, in conjunction, reduce water absorption by a maximum of 274%, have a contact angle equal to 86 degrees, and lower thermal conductivity by 55% in the dry state due to the specifics of the layer formed on the surface of WS. The addition of EG to LG coating resulted in insignificantly changed water absorption and thermal conductivity values, indicating the potential of this material to be used to improve the fire resistance of wood-based composites in the future. The results showed that the three-component layer of LG/TO/EG reduces water absorption by a maximum of 72%, increases thermal conductivity in the dry state by a minimum of 0.4%, and increases the contact angle to 81 degrees at 100 wt.% LG. The changes in water vapor permeability of all compositions were determined to be insignificant.

Automated summary

The study investigates the impact of liquid glass, tung oil, and expandable graphite coatings on the behavior of wood scobs as insulation materials. The thermal conductivity, water absorption, surface wettability, and water vapor permeability were evaluated under different coating compositions. The results show that liquid glass and tung oil together can significantly reduce water absorption and thermal conductivity. The addition of expandable graphite has a limited effect on the properties. The three-component coating of liquid glass, tung oil, and expandable graphite shows promising results in improving the fire resistance of wood-based composites.