Abstract: The finishing quality of wood products depends on the material's surface and its intrinsic properties. Dynamic wettability is a simple and efficient way to understand the behavior of materials related to solid-liquid interactions according to theoretical and practical perspectives. Thus, we sought to investigate the wettability of Imbuia (Ocotea spp.), Red oak (Quercus spp.), and Pine (Pinus elliottii) woods and its effects before and after sanding. Through the sessile drop technique, we evaluated contact angle and work of adhesion. Sanding changed the samples’ surface quality due to the decrease in contact angle and the increase in the work of adhesion. In addition, the droplet spreading and adsorption observed on the surface of the woods are an indicator of wettability. Pine and Red oak had their dynamic contact angle reduced by up to 43 %. However, Imbuia was less susceptible to the effects of sanding, since it was found to be a more hydrophobic species; thus, this wood has a more stable surface in terms of dynamic wettability. This may be a result of the effect of low molecular weight compounds on the surface of Imbuia wood. The preparation of the wood surface depends on a synergy between the finishing processes and the chemical composition of the surface. Therefore, the results found can indicate which coatings are more suited to these woods.

ABSTRACT Lignin, the second most abundant biopolymer on the planet, has properties that can be widely explored, moving from waste to products with high added value. Therefore, this work aimed to extract and characterize Klason and Kraft lignins from sawdust and black liquor, considered industrial waste. The raw material used was Eucalyptus grandis chips. To obtain Klason lignin according to TAPPI 222 om-02 (2002), part of the chips were transformed into sawdust. To obtain Kraft lignin, another part of the chips passed through a digester to obtain black liquor, which was subsequently subjected to acid precipitation. The characterization of lignins was performed by granulometry analysis, scanning electron microscopy with elemental chemical analysis (EDS), transmission electron microscopy, medium infrared spectroscopy, thermogravimetric analysis and differential calorimetry. Microscopy analyzes showed irregular structures of various shapes, including spherical structures, most evident and frequent in Kraft lignin. The elementary chemical analysis showed that the lignin washing process was satisfactory, due to the small percentage of sulfur detected in the samples. The results of the granulometry confirmed that the lignins had micrometric dimensions. The medium infrared spectra showed the characteristic peaks of the chemical composition of lignin. The thermal analysis showed three ranges of degradation, attributed to the drying of the samples, degradation of the hemicelluloses and the lignin itself. All results confirmed the obtaining of Klason and Kraft lignins. Therefore, the techniques were satisfactory in transforming waste into lignin with the potential for a variety of commercial applications, mainly in the chemical and pharmaceutical industries.

RESUMO A lignina, o segundo biopolímero mais abundante do planeta, possui propriedades que podem ser amplamente exploradas, passando de resíduos a produtos de alto valor agregado. Portanto, este trabalho teve como objetivo extrair e caracterizar as ligninas Klason e Kraft de serragem e licor negro, considerados resíduos industriais. A matéria-prima utilizada foram cavacos de Eucalyptus grandis. Para a obtenção da lignina Klason conforme TAPPI 222 om-02 (2002), parte dos cavacos foi transformada em serragem. Para a obtenção da lignina Kraft, outra parte dos cavacos passou por um digestor para a obtenção do licor negro, que posteriormente foi submetido à precipitação ácida. A caracterização das ligninas foi realizada por análise de granulometria, microscopia eletrônica de varredura com análise química elementar (EDS), microscopia eletrônica de transmissão, espectroscopia de infravermelho médio, análise termogravimétrica e calorimetria diferencial. As análises microscópicas mostraram estruturas irregulares de vários formatos, incluindo estruturas esféricas, mais evidentes e frequentes na lignina Kraft. A análise química elementar mostrou que o processo de lavagem da lignina foi satisfatório, devido ao pequeno percentual de enxofre detectado nas amostras. Os resultados da granulometria confirmaram que as ligninas apresentaram dimensões micrométricas. Os espectros de infravermelho médio mostraram os picos característicos da composição química da lignina. A análise térmica mostrou três faixas de degradação, atribuídas à secagem das amostras, degradação das hemiceluloses e da própria lignina. Todos os resultados confirmaram a obtenção das ligninas Klason e Kraft. Portanto, as técnicas foram satisfatórias na transformação de resíduos em lignina com potencial para diversas aplicações comerciais, principalmente nas indústrias química e farmacêutica.

The near infrared (NIR) spectroscopy presents it self as an interesting non-destructive test tool as it enables a fast, simple and reliable way for characterizing large samplings of biological materials in a short period of time. This work aimed to establish multivariate models to estimate the crystallinity indices and tensile and burst strength of cellulosic and nanocellulosic films through NIR spectroscopy. NIR spectra were recorded from the films before tensile and bursting strength, and crystallinity tests. Spectral information were correlated with reference values obtained by laboratory procedures through partial least square regression (PLS-R). The PLS-R model for estimating the crystallinity index presented a coefficient of determination in cross-validation (R²cv) of 0,94 and the ratio of performance to deviation (RPD) was 3,77. The mechanical properties of the films presented a high correlation with the NIR spectra: R²p = 0,85 (RPD = 2,23) for tensile and R²p = 0,93 (RPD = 3,40) for burst strength. The statistics associated to the models presented have shown that the NIR spectroscopy has the potential to estimate the crystallinity index and resistance properties of cellulose and nanocellulose films on in-line monitoring systems.

Samples of wood sold as "angelim" in Brazil were studied. Disks from the trunks of Diplotropis purpurea, Hymenolobium petraeum, Parkia pendula, Vatairea guianensis and Vatairea paraensis were obtained from Mato Grosso state. Samples from pith to bark of each species were obtained, oriented in the three anatomical planes. Each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min-1. The description of the anatomical elements of wood and charcoal samples followed the orientations of the International Association of Wood Anatomists, on the basis of 25 readings regarding frequency and tangential diameter of the vessels and height and width of the rays in micrometers. Infrared analyses were performed with a Bruker Tensor 37 spectrophotometer equipped with an integrating sphere and operating in reflectance mode, with resolution of 4 cm-1 and a spectral range of 10000-4000 cm-1. The wood and charcoal samples were placed on top of integrating sphere and one spectrum was obtained from each surface, resulting in six spectra for each physical sample. The results of anatomical analysis showed that the qualitative characteristics of wood remained in charcoal, so the method can be applied for species discrimination. When comparing cell dimensions, we observed different behavior between species in the same carbonization process in function of cell wall thickness and parenchyma distribution. In infrared analysis, pretreatment influenced adequate discrimination of "angelim" species in wood and charcoal. Linear discriminant analysis based on PCA scores and the region between 4000-6200 cm-1 was more efficient. Near infrared analysis can be used for differentiation of wood and charcoal of "angelim" species.

In Brazil, the cultivated species of genus Salix have great importance in crafts, with different properties in relation to malleability and resistance. This paper aimed to apply near infrared spectroscopy (FT-NIR) for discrimination of four Salix species, comparing solid sample and particulate material. Samples from Salix viminalis, Salix x rubens, Salix purpurea and Salix sp. were collected in seven sites in the region of Rio Canoas Valley, Santa Catarina State, Brazil. It was obtained absorbance spectra in FT-NIR (Bruker Tensor 37). The shape and particle size of Salix spp. influenced the discrimination of species by near infrared. The technique had a more efficient distinction for smaller particle size samples.

En Brasil, las especies cultivadas del género Salix son de gran importancia en la artesanía, con propiedades diferentes en relación a la maleabilidad y resistencia. Este trabajo tuvo como objetivo aplicar la espectroscopía de infrarrojo cercano (FT-NIR) para la discriminación de cuatro especies de Salix, comparando muestras de materia maciza y partículas. Las muestras de Salix viminalis, Salix x rubens, Salix purpurea y Salix sp., fueron seleccionadas en siete sitios en la región del Valle del Río Canoas, Estado de Santa Catarina (Brasil). Los espectros de absorción se obtuvieron en FT-NIR espectrofotómetro (Bruker Tensor 37). La forma y la granulometría de las muestras de Salix spp. tienen influencia en la discriminación de las especies por FT-NIR. La técnica tuvo mayor capacidad de distinción para la granulometría de menor tamaño.

A busca por novas tecnologias que garantam a uniformidade da qualidade dos produtos tem se tornado constante, assim este trabalho teve como objetivo estudar a potencialidade de medidas espectroscópicas combinadas a ferramentas estatísticas para classificação de lâminas de madeiras de Pinus spp. contaminadas por fungos manchadores. As amostras foram coletadas em processo industrial, e observou-se que algumas lâminas estavam contaminadas por fungos manchadores. Assim, utilizou-se este material para investigar a influência dessa mancha azul em metodologias espectroscópicas e a possibilidade de discriminação dessa contaminação. Desse material contaminado foram capturados os espectros, na faixa de 400 a 1000 nm. Com esses dados, realizou-se uma análise exploratória por Componentes Principais (PCA) e classificação via SIMCA, em que se verificou a discriminação eficiente em dois grupos, madeiras sadias e contaminadas. Observou-se que a técnica de espectroscopia óptica preenche os requisitos necessários para uma possível aplicação na classificação de lâminas no processo produtivo.

The search for new technologies that ensure uniformity of product quality has become constant. The objective of this work was to study the potential of spectroscopic measurements combined with statistical tools for sorting sheets of wood of Pinus spp. contaminated by staining fungi. Samples were collected in the industrial process and it was found that some blades were contaminated by fungus staining. Thus, this material was used to investigate its influence on blue stain and spectroscopic methods and the possibility of discrimination by such contamination. Spectra at 400-1000 m range were captured from this contaminated material. By using these data, it was performed an exploratory analysis by Principal Components (PCA) and classification via SIMCA, where discrimination was found effective in healthy and diseased wood. It is observed that the use of optical spectroscopy fulfills the requirements for possible use in classifying blades in the production process.

RESUMO O conhecimento das propriedades da madeira é de fundamental importância para indicação dos potenciais de utilização final deste material. Na busca por novas alternativas para caracterização rápida, simples e confiável, destacam-se as avaliações não destrutivas da madeira. A espectroscopia no infravermelho próximo (NIRS) vem sendo utilizada como método não destrutivo que permite obter informações qualitativas e quantitativas dos constituintes da biomassa através da interação das ondas eletromagnéticas do infravermelho próximo com a amostra. Este trabalho tem como objetivo fornecer uma revisão sobre a técnica da espectroscopia no infravermelho próximo e sua aplicação no setor florestal. A técnica está presente em praticamente todas as áreas, devido ao nível de desenvolvimento que esta tecnologia atingiu nos últimos anos. A espectroscopia NIR tem se mostrado uma ferramenta rápida e eficiente para substituição dos diversos ensaios que determinam a qualidade da madeira.

ABSTRACT The knowledge of wood properties is the fundamental importance for the indication of the potential and use of this material. In the search for new alternatives for a fast, simple and reliable characterization, there are the non-destructive evaluations of wood. The near infrared spectroscopy (NIRS) has been used as a non-destructive method that allows qualitative and quantitative information of the constituents of biomass through the interaction of electromagnetic waves with near-infrared next to the sample. This work aims to provide a review of the technique of near infrared spectroscopy and its application in forestry. The technique is used in virtually all areas due to the level of development that this technology has reached in recent years. NIR spectroscopy has proved a quick and efficient replacement of several tests that determine the quality of the wood. This is a literature review and state of the art on the theme.