Sines, Portugal
Sines, Portugal

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Henriques A.,University of Porto | Cruz P.,Industrias Quimicas SA | Ferra J.M.,Industrias Quimicas SA | Martins J.,University of Porto | And 4 more authors.
Wood Science and Technology | Year: 2013

Melamine-urea-formaldehyde resin production has increased in the last years due to low formaldehyde emissions and improved moisture resistance when applied on wood-based panels. Melamine is a relatively high-cost raw material in the resin formulation and has a significant effect on wood-based panel properties. It is important for industry to implement efficient quality control methods to determine melamine content in resins. The main objective of this work was to develop chemometric techniques for off-line monitoring of melamine content using near-infrared spectroscopy. The use of interval partial least squares regression allowed identifying the most interesting spectral ranges for analysis (4,400-4,800 and 5,200-5,600 cm-1) and the best preprocessing methods to use in the determination of this property. When the appropriate spectral range and preprocessing methods are selected, it is possible to obtain calibration models with high correlation coefficients. © 2013 Springer-Verlag Berlin Heidelberg.


Costa N.A.,University of Porto | Costa N.A.,Industrias Quimicas S.A. | Ferra J.,Industrias Quimicas S.A. | Martins J.,University of Porto | And 7 more authors.
International Wood Products Journal | Year: 2014

Polyvinyl acetate (PVAc) adhesives present several advantages: ready to use, short setting time, flexible joint, easy to clean and long storage life. On the other hand, formaldehyde-based adhesives are less expensive and give a rigid bond. In this work, the combination of a PVAc glue and UF resin for surfacing MDF with wood veneer was assessed. The reactivity of different mixing ratios was evaluated using ABES (automated bonding evaluation system) machine as well as the wettability of beech veneers after different heat pre-treatments. The obtained results have shown that a mixture of PVAc/UF could be used for surfacing MDF with beech veneer without loss of mechanical properties, when compared with pure PVAc. © 2014 IWSc.

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