A raw pine resin, which is a cheap, renewable and easily obtainable forest resource, was used to impregnate two different fast-growing solid woods (Eucalyptus grandis Hill Maiden and Pinus elliottii Engelm) and in situ polymerized to improve their hygroscopic, chemical, morphological, mechanical, and thermogravimetric properties. Biodegradation resistance against subterranean termites and white-rot fungus was also addressed. The treatment yielded changes in colorimetric properties, dimensional stability and surface hydrophobicity. Compared to its respective untreated wood, the treated pine one presented increases within 40-50 % in ASE, whereas the treated eucalyptus wood showed negative values around -15 % in this same comparison. Increases in MOE (70 %) and MOR (50 %) were obtained for the pine wood, whereas the same properties were unaffected for the eucalyptus wood. Thermal and biological properties of both woods were also positively affected. These results were associated with the solidified raw pine resin inside the wood structure, which was confirmed by infrared spectroscopy and SEM images, especially for the pine due to its large and long tracheids, as well as its lignin content and overall composition.

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Abstract. This work deals with the synthesis of alumina gels from aqueous solutions of aluminum chloride in the presence of cationic surfactant molecules. The effect on the sol-gel transition of the reagent concentrations and of the synthesis temperature are first studied. The structure of the resulting wet and dried gels and the formation of liquid crystal mesophases are studied by X-ray diffraction. The thermal and structural evolutions of the gels are then characterized by thermogravimetric and X-ray diffraction measurements. Finally, nitrogen adsorption isotherms are used to investigate the porous texture of the thermally treated materials up to the transformation into ot-A1203.

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