Physical properties and formaldehyde emission in particleboards of Eucalyptus sp. and ligno-cellulosic agro-industrial waste

Abstract

The aim of the paper was to evaluate particleboards made from eucalypt wood in combination with waste from agricultural activity (carpels of macadamia nuts, coffee husks, and papaya stalks), using urea-formaldehyde and tannin-urea-formaldehyde adhesives. The apparent density, water absorption (after 2 and 24 hours of immersion), thickness of swelling (after 2 and 24 hours of immersion) and emission of formaldehyde were analyzed. The majority of particleboards was classified as of medium density; the increase in the percentage of wastes on composition and the addition of tannic extract in urea-formaldehyde promoted the reduction of the physical properties; the particleboards attended performance specifications for water absorption and thickness swelling. The increase of tannic extract in the urea-formaldehyde adhesive reduced the free formaldehyde emission by 22.5% in the particleboards. The results indicate a potential of the wastes to be used as raw material to produce particleboards where these technological properties are required.