Sugar-lignocellulosic composites: The incorporation of two simple saccharides into moulding as additives
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[1] Universidad de Concepción
Universidad de Concepción
Comuna de Concepción, Chile
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- Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 48, Nº. 4, 2003, págs. 55-61
- Idioma: español
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Resumen
Wood veneer of pine (Pinus radiata D. Don) and eucalyptus (Eucaliptus globulus ssp. globulus Labill) were analyzed by means of Dynamic Mechanical Analysis (DMA). Previously, they were saturated with buffer phosphate (pH=4), fructose and maltose (2%) solutions. The viscoelastic behavior and temperatures of relaxation of wood in both species were differents, the effect was attributed to its chemical difference. This behavior is changed in both species by sugars presence generating plasticizing effects, being more marked in presence of maltose than fructose. Between species, the pine wood presents the most important changes of its viscoelastic properties. With this information, molding samples from both species, made with mixture of particles (0.25 mm) of bark (49%), wood (49%) and sugars 2%, were obtained using pressure and temperature controlled. They were essayed for determinate the internal bond considering the Modulus of rupture (MOR). According to Multiple Linear Regression Analyses (MLR), with a 95% of confidence, the variation of the MOR is explained in 68% of the cases by the particular specie, wood and bark, moisture content, time of impregnating and type of sugar. The large values of the MOR are produced by a greater amount of hydroxyls groups contributed by maltose producing the greater plasticizing effect and the greater union between particled lignocellulosic materials. The minor water content generated the greater MOR, this is attributed to its plastizicing effect, it means that dependency of the water content under the saturation point of the fiber is not directly proportional to the plastizicing effect
