Because of the species similarity and the need to differentiate wood of the Myrtaceae family, this study aimed to evaluate the potential of near-infrared spectroscopy for discrimination of wood and charcoal from Campomanesia xanthocarpa Berg, Eugenia pyriformis Cambess., Myrcia retorta Cambess. and Plinia peruviana (Poir.) Govaerts, native of the Araucaria Forest. For each evaluated species, three trees were collected and a disk at breast height was cut and divided into samples obtained in the region near the pith, intermediate and near the bark. For each sample, two spectra were obtained in each anatomical section (transversal, radial and tangential) in the region from 4000 to 10,000 cm⁻¹. Results indicated the similarity of wood and charcoal spectra of all species, and principal component analysis (PCA) of raw data on samples showed little distinction of species, but second derivative pretreatment provided adequate discrimination. When evaluation was based on anatomical sections and position in trunk, for wood in all positions (near bark, intermediate, near pith) it was possible to separate species, but for charcoal some more samples dispersion were observed. Linear discriminant analysis corroborated the results of PCA. Near-infrared spectroscopy presented adequate results and the potential to help discriminate wood and charcoal of the four Myrtaceae species.

The aim of this study was to verify the potential of the colorimetric technique in the identification of some species marketed as "tauari" in the Brazilian Amazon. CIE L* a* b* parameters were applied to determine the colour of 35 wood samples from the main wood poles of the State of Para, Brazil, and the scientific collections of the Museu Paraense Emilio Goeldi (Walter A. Egler Collection) and Embrapa Amazônia Oriental. From each sample, data were obtained in the three wood surfaces: transversal, longitudinal tangential and longitudinal radial. The coordinate b*, which showed the yellow pigment, exerted greater weight in the color characterization of the 35 samples marketed as tauari, being more evident in the tangential and radial sections. In PCA, MGW wood samples showed considerably distinct color patterns in relation to PA and IAN samples, and the h and L* parameters provided better informations for distinguishing species from sample sources. The colorimetric technique can be used as an auxiliary tool in the identification of wood. However, the simultaneous use of colorimetry with the anatomical description of wood is suggested, given the complexity of the species-level separation in "tauari" group.

The objective of this study was to use colorimetry and visible spectroscopy to discriminate wood species obtained from the Amazon floodplain, in addition to determining the basic density and relating it to the wood colorimetric parameters. The studied material was from a community forest management area in the state of Amazonas, Brazil. For colorimetric and visible spectrum analyses, data were obtained randomly in the transverse anatomical surface. The spectral behavior of the wood samples in the visible region was evaluated. In the statistical analyses, comparisons of colorimetric parameters and visible spectra of wood from floodplain tree species were carried out. Furthermore, the basic density of the wood was determined. The best differentiation of species was achieved mainly by the hue angle. The species Pseudobombax munguba (Mart.) Dugand presented the highest median for the coordinate of the red-green axis, and the medians of the species P. munguba and Hevea spruceana (Benth.) Müll.Arg. obtained higher values of the blue-yellow axis coordinate and saturation. All species evaluated were classified as light and having low-density wood. Thus, it can be concluded that the colorimetric technique has potential to distinguish Amazon floodplain forest species.

In this study, based on the mechanical shear treatment, the cellulosic pulp was fibrillated in nanofibrils dispersed in aqueous suspension. Nanofibrillated Cellulose (NFC) matrix - Polyvinyl Alcohol (PVA) nanocomposite films’ were prepared by casting from NFC/PVA suspension mixtures. The thermal and mechanical properties of the obtained films were evaluated. Low levels (2, 5 and 10 wt%) of PVA were used as an additive in a nanofibrillated cellulose (NFC) matrix. The predominant use of NFC, with superior properties due to its purity, with an efficient and environmentally friendly method, has allowed the production of NFC-based biodegradable materials with enhanced properties for high-level applications. The addition of PVA to the NFC matrix produced positive results, as it causes little aesthetic interference, without changes in surface brightness. After the addition of PVA the films showed a great gain in mechanical strength, increasing by 24% in Young’s modulus with the addition of 10% PVA. Even after addition, the samples’ chemical composition remains unchanged and the mixture shows a decrease in the film surface hydrophilicity when compared to pure NFC. Composite material thermal analysis indicates that thermal degradation temperatures remain unchanged after the addition of PVA. Although PVA is not very temperature resistant, in the proportions used, NFC thermal resistance is preserved.