engleski

Properties of particleboards produced by catalytic reaction of liquified wood on urea-formaldehyde resins

Wood composite materials and fragmented wood-based panels, respectively, are materials of the future. With their wide spectra of potential applications these materials occupy almost all fields of use. The quality of wood composite materials does not exclusively depend on wood species and their properties applied in production, but with application of other non-wood necessary synthetic chemical components, such as various resins, catalysts and paraffin emulsion, are designed in accordance with the application requirements. Regarding to this issue, the aim of this study was to use liquefied wood (LW) as a catalyst (hardener) in the polymerization process of urea-formaldehyde (UF) resins at elevated temperatures, and the influence of its reaction on particleboards physical-mechanical properties and formaldehyde emission. The studies have been carried out on experimental three-layer particleboards made with catalysts for UF resins polymerization, which is commonly used for the commercial production, namely ammonium chloride, NH4Cl, and ammonium sulfate, (NH4)2SO4. Furthermore, under the same conditions, particleboards with liquefied wood as a catalyst were produced, and based on the testing results the comparison with the above mentioned catalysts had been made. The liquefied wood was not especially prepared before use, but extremely acidic nature of its components, that enabled liquefaction, was used. The research results showed that liquefied wood as a catalyst has a positive effect on the polymer structure and adhesion-cohesion properties of UF adhesives, and also on the particleboards physical-mechanical properties and formaldehyde emission, so it successfully replaced the commercial types of catalysts.

liquefied wood; urea-formaldehyde resin; catalysts; particleboards

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