Treatment of wood with thermosetting resins: Effect on dimensional stability, strength and termite resistance

Abstract

The effect or thermosetting resins <i>viz</i>. phenol formaldehyde (<i>PF</i>)<i> </i>and melamine formaldehyde (<i>MF</i>)<i> </i>on dimensional stability, strength property and termite (<i>Odontotermis </i>spp) resistant capacity of a soft wood, <i>bombax ceiba </i>were assessed. The wood was treated with 30% resin concentration in 110°C at 75 psi air pressure and then dimensional stability in terms of anti-shrink efficiency (<i>ASE</i>) of 70.59% and 68.23% were achieved at 32.1 and 33.0 levels of weight percent gain (<i>WPG</i>) for <i>PF </i>and <i>MF </i>resins respectively. Maximum bulking co-efficient (<i>BC</i>)<i> </i>of 15.39% and 13.28%, and moisture excluding efficiency (<i>MEE</i>)<i> </i>or 45.31% and 41.39% were achieved for <i>PF </i>and <i>MF </i>treated samples at the above two <i>WPG </i>levels. Three cycles of repeated wetting and drying did not cause any further change in <i>BC </i>and <i>ASE</i>. The treatment also increased modulus of rupture (<i>MOR</i>)<i> </i>by 21.6% and 19.48% and modulus of elasticity (<i>MOE</i>)<i> </i>by 12.86% and 11.10% over the untreated samples without any remarkable change in specific gravity. Furthermore, the treated wood showed resistant termite.