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Author(s): Nuno Costa
João Pereira
Jorge Martins
João Ferra
Paulo Cruz
Fernão Magalhães
Adélio Mendes
Luísa Carvalho
Title: Alternative to latent catalysts for curing UF resins used in the production of low formaldehyde emission wood-based panels
Issue Date: 2012
Abstract: This paper studies alternative catalysts to ammonium sulfate for curing urea-formaldehyde (UF) resins. When using a latent catalyst like ammonium sulfate, hexamine is formed as by-product of curing reaction. It is believed that hexamine hydrolysis may contribute to formaldehyde release during the life-time of wood-based panels produced with UF resins. Orthophosphoric acid, on the other hand, catalyzes resin cure without by-product formation and was compared to ammonium sulfate. The pot-life of adhesives with both catalysts was evaluated at 40 degrees C with a Brookfield rheometer. Mechanical resistance tests performed with ABES (Automated Bonding Evaluation System) showed that orthophosphoric acid effectively catalyzes UF resin cure. Particleboards were produced using both catalysts and the most important properties evaluated, according to European Standards: formaldehyde content, internal bond, moisture content, thickness swelling and density. Particleboards cured with orthophosphoric acid and stored under forceful conditions of humidity and temperature presented similar internal bond and lower formaldehyde content than those produced with ammonium sulfate.
Subject: Engenharia química
Chemical engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia química
Engineering and technology::Chemical engineering
Related Information: info:eu-repo/grantAgreement/Agência de Inovação, S.A./Projectos de I&DT em Co-Promoção/SI IDT - 5347/2008/Concepção de sistemas adesivos taylor-made para o fabrico de painéis de madeira de baixa emissão de formaldeído/EO_Formaldehyde
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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