The distribution of silicon atoms in sugi wood treated with gamma-methacryloxypropyl trimethoxysilane and its fire retardancy

Attempts to increase the dimensional stability and fire retardancy of sugi wood have already been undertaken by using gamma -methacryloxypropyl trimet hoxysilane (MS) monomers. Dimensional stability is thought to be influenced by the existence of sites in which MS polymers are located. In order to ex amine the sites in sugi wood where MS polymers exist, the distribution of s ilicon atoms from siloxane linkages in MS-treated sugi wood was obtained. T o investigate the relationship between fire retardancy and the distribution of silicon atoms, the fire retardancy of the surface of the specimen used for Si detection was determined. According to Si atom mapping, silicon exists throughout the entire cell wal l. Therefore, MS monomer was introduced into the cell wall and polymerized there by the MS treatment. Si atom density decreased as the perpendicular d istance from the surface increased. Therefore the penetration of MS monomer declined with increasing distance from the surface of cross section, resul ting in high density of MS polymer in the surface layer compared with the i nside of the MS-treated sugi wood. Fire retardancy tests showed that the ig nition time was shortened as the perpendicular distance from the surface of the cell wall increased. Specimens with low density of Si atom had short i gnition times, revealing a correlation between fire retardancy and Si densi ty for MS-treated sugi wood.