Original paper(Vol.48 No.3 pp.245)
Some o of Wood-Mineral Composites Using the Colloidal Silica Solution System -Termite Resistance,Photo Stability,Hardness, and Abrasion Resistance-
Furuno Takeshi; Imamura Yuji; Asada Osamu; Katoh Sadanobu
Abstract:Following the previous paper treating with the production and properties of wood mineral composites using the colloidal silica solution system, we investigated termite resistance, photo stability, hardness, and abrasion resistance of composites. The composites were prepared by the same process previously reported using a colloidal silica solution and sapwood or heartwood of Sugi (Cryptomeria japonica D. Don).
The composites made by using the colloidal silica boric acid system showed an excellent termite resistance with the neglible weight losses of specimens and 100% mortalities of workers and soldiers, and the metal compounds (Cu, Ag, and Ti) added system had a certain extent of resistance against termite attack.
As a result of photo stability test with ultraviolet (UV) light, the changes in color difference in the radial section of the composites irradiated with UV light were smaller than those of the untreated wood, particularly the smallest change for the titanium dioxide added system, showing the enhancement of photo stability. The composites remained the photo proof even after leaching. The brightness in the cross section changed greatly in the boric acid and titanium dioxide added system compared with the untreated wood.
The Brinell hardness in the cross section showed an increase up to 70% compared with the untreated wood, and it increased with an increase in weight percent gain (WPG). This hardness held an increase up to 22% compared with the untreated wood even after leaching and the hardness in the radial section increased up to 30%, revealing little reduction of hardness in any case. The Taber type abrasion index in the tangential section tended to increase with an increase in WPG. This result showed the reduction of abrasion resistance.
Key Words:wood-mineral composite, colloidal silica, silica acid gel, boric acid, titanium dioxide, termite resistance, photo resistance, hardness, abrasion resistance, sugi