Some properties of mood-mineral composites using the colloidal silica solution system－ termite resistance, photo stability, hardness and abrasion resistance

摘要

Following the previous paper treating withthe production and properties of wood-mineralcomposites using the colloidal silica solution system,we investigated termite resistance, photo stability,hardness, and abrasion resistance of composites. Thecomposites were prepared by the same process previouslyreported using a colloidal silica solution and sapwoodor heartwood of Sugi (Cryptomeria japonica D. Don).Thecomposites made by using the colloidal silica-boricacid system showed an excellent termite resistance withthe neglible weight losses of specimens and 100%mortalities of workers and soldiers, and the metalcompounds (Cu, Ag, and Ti)-added system had a certainextent of resistance against termite attack.. As aresult of photo stability test with ultraviolet (UV)light, the changes in color difference in the radialsection of the composites irradiated with UV light weresmaller than those of the untreated wood, particularlythe smallest change for the titanium dioxide-addedsystem, showing the enhancement of photo stability. Thecomposites remained the photo proof even after leaching.The brightness in the cross section changed greatly inthe boric acid-and titanium dioxide-added systemcompared with the untreated wood. The Brinell hardnessin the cross section showed an increase up to 70%compared with the untreated wood, and it increased withan increase in weight percent gain (WPG). This hardnessheld an increase up to 22% compared with the untreatedwood even after leaching and the hardness in the radialsection increased up to 30%, revealing little reductionof hardness in any case. The Taber type abrasion indexin the tangential section tended to increase with anincrease in WPG. This result showed the reduction of abrasion resistance.