After cellulose, lignin is, the second most abundant component in wood. In the pulping industry, the introduction of modern Kraft pulping technologies could produce chemical modification in lignin's functional groups. Kraft lignins from Eucaliptus nitens and Pinus radiata industrial black liquors were isolated by acid precipitation. An organosolv lignin was obtained from spent liquor from the P.radiata wood pulping process. All lignins were acetylated with acetic anhydride and characterized by Fourier-transformed infrared spectroscopy (FT-IR). Analysis based on the IR-fingerprint spectral region indicates several differences in the functional groups of the different types of lignins. The thermal behaviour of unmodified and acetylated lignins were studied by differential scanning calorimetry (DSC) and the glass transition temperatures (Tg) were determined and compared with values reported in the literature. The acetylated lignins show a decrease in the Tg values which is probably due, to the at plasticization effect of the acetylation reaction.

The objective of this study was to evaluate the tannin extraction potential taken from the bark of Acacia dealbata. This tannins were extracted with water at 90°C. An extraction yield of 17.2% solids with a Stiasny number of 82% was obtained from the bark extract of Acacia dealbata. The structure was studied by Fourier transform infrared spectroscopy (FTIR). The thermal behavior of tannins was studied by DSC and a glass-transition temperature (T g ) of 116,77°C was determined. The thermal stability of tannins was studied by TGA. At 196.91°C the decomposition is 3.7% and the maximum of the weight loss rate (DTG) of the degradation was 257.77°C. The curing with formaldehyde showed an exotherm reaction in the range of 100-120°C, which is similar to tannins of other species.

RESUMENPolipropileno reciclado (rPP) proveniente de rafia sintética de grandes sacos postconsumo, fueron reforzados con 50 y 60% de harina de madera de Pinus radiata de dos tamaños de partícula (60 y 100 mesh) a través de un proceso de mezclado en fundido, con y sin polipropileno maleado (MAPP), utilizado como agente acoplante. La procesabilidad de rPP y de compositos a base de madera-rPP fue estudiada en términos del torque del proceso de mezcla, al igual que las propiedades físicas, térmicas y mecánicas, y comparadas con polipropileno virgen (PP).Los resultados mostraron que la resistencia a la tracción y a la flexión (MOR), módulos determinados en tracción y en flexión (MOE) y resistencia al impacto de rPP y de los compositos madera-rPP, no decrecen comparadas con PP virgen y en términos de los módulos de elasticidad (MOE) y resistencia al impacto son significativamente superiores. Las propiedades mecánicas de las mezclas mejoraron levemente con la presencia de MAPP pero el tamaño de partícula y el contenido de harina de madera (50 y 60%), no tuvieron una clara influencia en estas propiedades.Calorimetría diferencial de barrido (DSC) fue utilizada para estudiar las propiedades de cristalización y fusión de las muestras y los resultados fueron comparados con PP virgen. Los resultados indican que la harina de madera actúa como un agente de nucleación incrementando la velocidad de cristalización, disminuyendo el grado de cristalización y en consecuencia disminuyendo ligeramente el punto de fusión de los compositos madera-rPP.El análisis termogravimétrico (TGA), mostró que la estabilidad térmica de rPP y de los compositos maderarPP fue ligeramente superior a la de PP virgen.En general, los resultados de este estudio muestran que es factible obtener materiales compuestos de buenas propiedades térmicas y mecánicas utilizando rPP postconsumo reforzado con harina de madera, en proporciones de 50 o 60% de contenido.Palabras claves: Harina de madera, polipropileno reciclado, propiedades térmicas, propiedades mecánicas.

In this work, the changes caused by a chemical modification of the properties and chemical structures of lignin are studied. Lignin from a mixture of Eucalyptus globulus and Eucalyptus nitens obtained through the kraft pulping process was used. The lignin was isolated by acid precipitation and modified by a reaction with maleic anhydride. Maleated lignin (ML) was incorporated to recycled polystyrene (rPS) at 2, 5, and 10 wt-% by a melt-blending process. Fourier transformed infrared spectroscopy (FT-IR) was used to determine the ML structure, and the morphology of rPS/ ML composites was studied by scanning electron microscopy (SEM).Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the glass-transition temperature (T g ) and the thermal stability of rPS and rPS/ ML composites and were compared with virgin PS. The T g values of rPS and their composites were higher than those of the virgin PS. TGA revealed that the thermal stability of rPS with 2 and 5% of ML was slightly greater than that of the virgin PS. These results suggest that postconsumer PS can be used to obtain composite materials with good thermal properties.

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