Extração e caracterização de duas ligninas residuais da madeira de eucalipto

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.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

CHARACTERIZATION OF CELLULOSE AND CELLULOSE NITRATE NANOFILMSSE

The objective of this work was the characterization of cellulose and cellulose nitrate nanofilms from the mixture of Kraft pulps of  Pinus sp. and Eucalyptus sp. bleached. The production of nanocellulose was made by mechanical processing. To obtain the cellulose nitrate, the nitration was carried out in part of the produced nanocellulose. The characterizations were performed by means of scanning electron microscopy, medium infrared spectroscopy, tensile strength and absorption assay.  The results demonstrate that there was influence of  nitration in the characteristics of the films produced. The nanofilms of cellulose nitrate appear more interesting for the absorption property, indicating the use of this process for uses that require this characteristic

INFLUÊNCIA DA ÉPOCA DE ESTOCAGEM NA QUALIDADE DA BIOMASSA FLORESTAL PARA A GERAÇÃO DE ENERGIA

Este trabalho objetivou determinar a época de estocagem ideal para a melhoria da qualidade da biomassa florestal para geração de energia. O experimento foi realizado em Lages, SC, entre outubro de 2003 e fevereiro de 2005. Foram avaliados 4 lotes de toras com casca de Pinus taeda e Eucalyptus dunnii, em pilhas, com amostragem nas seguintes condições: material recém-colhido, com dois, quatro e seis meses de estocagem. O lote 1 foi armazenado entre outubro (2003) e maio (2004), o lote 2, de janeiro a agosto de 2004, o lote 3, de maio a novembro de 2004 e o lote 4, de agosto de 2004 a fevereiro de 2005. As propriedades avaliadas foram: teor de umidade na base úmida, poder calorífico superior e líquido. A época de estocagem teve influência sobre a qualidade energética da biomassa durante a estocagem, com alterações na umidade e poder calorífico líquido. Para ambas as espécies, as melhores épocas de estocagem foram entre agosto e fevereiro (lote 4) e outubro e maio (lote 1), com as maiores perdas de umidade e maiores ganhos energéticos. Portanto, a biomassa florestal colhida na saída do inverno ou início da primavera, que permaneceu sob estocagem durante o verão até o início do inverno, apresentou melhor qualidade energética.Palavras-chave: Energia; Pinus taeda; Eucalyptus dunnii. AbstractInfluence of the storage season over the quality of wood fuel. This study aimed to determine the optimal storage season for improving the quality of forest biomass for energy generation. The experiment was carried out in Lages, Brazil, between October 2003 and February 2005. 4 lots of Pinus taeda and Eucalyptus dunnii logs were stocked, in piles, with samples collected from the freshly harvested material, with two, four and six months of storage. The lot 1 was stored between October (2003) and May (2004), lot 2 (January-August (2004)), lot 3 (May-November (2204)) and 4 (August (2004)-February (2005)). The evaluated properties were as follows: moisture content on wet basis, gross and net calorific value. The storage season had influence on the biomass quality, with changes in moisture content and net calorific value. For both species, the best storage season was between August and February (lot 4) and from October to May (lot 1), with the greatest loss of moisture and higher energy savings. Therefore, forest biomass harvested in late winter or early spring, which remained in storage during the summer up to early winter had a better energy quality.Keywords: Energy; Pinus taeda; Eucalyptus dunniiThis study aimed to determine the optimal storage season for improving the quality of forest biomass for energy generation. The experiment was carried out in Lages, Brazil, between October 2003 and February 2005. 4 lots of Pinus taeda and Eucalyptus dunnii logs were stocked, in piles, with samples collected from the freshly harvested material, with two, four and six months of storage. The lot 1 was stored between October (2003) and May (2004), lot 2 (January-August (2004)), lot 3 (May-November (2204)) and 4 (August (2004)-February (2005)). The evaluated properties were as follows: moisture content on wet basis, gross and net calorific value. The storage season had influence on the biomass quality, with changes in moisture content and net calorific value. For both species, the best storage season was between August and February (lot 4) and from October to May (lot 1), with the greatest loss of moisture and higher energy savings. Therefore, forest biomass harvested in late winter or early spring, which remained in storage during the summer up to early winter had a better energy quality

NANOCELLULOSE OBTAINED MECHANICALLY BY DIFFERENT COLLOID GRINDING INTENSITIES

Recent advances in nanocellulose technology have enabled production of materials for various applications with attractive properties. The aim of this work was to analyze the nanofibrillated cellulose of Eucalyptus sp. obtained by different grinding intensities. Delignified Eucalyptus sp. kraftpulp was used to obtain the nanofibrillated cellulose in the mechanical grinding process, with 2, 10 and 20 passes. Images were captured by scanning and transmission electron microscopy to observe cellulose structures. For each mechanical treatment, three films were produced, which were used to evaluate the crystallinity index. Viscosity measurement evaluated the influence of mechanical treatment on nanofibrillated cellulose. Microscopic analysis showed that the mechanical process promoted fiber defibrillation, resulting in the exposure of microfibrils in all treatments evaluated. Differences were not verified in the conformation and dimensions of the structures for the different numbers of passes, and the nanofibrils presented average diameter of approximately 30 nm. The mechanical process to obtain the nanofibrillated cellulose reduced of the crystallinity index and the viscosity of the nanofibrillated cellulose compared to cellulose before processing. The average particle size declined with rising number of grinder passes

INFLUÊNCIA DA ADIÇÃO DE CELULOSE NANOFIBRILADA (CNF) NAS PROPRIEDADES ÓPTICAS E FÍSICAS DO PAPEL

O objetivo deste trabalho foi avaliar a influência da incorporação de celulose nanofibrilada (CNF) sobre as propriedades ópticas e físicas do papel. Foi utilizada polpa Kraft branqueada de Eucalyptus sp. para produção das folhas. Para produção da CNF, a polpa foi processada mecanicamente no moinho desfibrilador Super Masscolloider Masuko Sangyo. Para visualização das estruturas e dimensões da celulose e da CNF, foi usada a microscopia eletrônica de transmissão e de varredura. A viscosidade foi usada para verificar o grau de polimerização das amostras. O índice de cristalinidade foi obtido usando difração de Raios-X. Foram confeccionados papéis com grau de refinação 15 e 25 °SR, com adição de 0% a 6% de CNF. Na sequência, estes foram avaliados por meio das propriedades ópticas (alvura e opacidade) e propriedades físicas (espessura, densidade aparente e permeância ao ar). O processo mecânico gerou o desfibrilamento interno e externo, promovendo a redução nas dimensões das fibras para a escala nanométrica. O processo de desfibrilação também causou a redução da cristalinidade e da viscosidade. De forma geral, as pequenas variações observadas para a alvura e a opacidade, bem como os aumentos significativos na densidade aparente e na resistência à passagem ao ar possibilitam a utilização da celulose nanofibrilada como um material renovável e biodegradável na produção de papéis

Colorimetric characterization of three wood species from the amazon forest

The aim of this study was to analyze wood color variability in the (radial, tangential and transversal) anatomic sections of Breu-vermelho, Tauari-vermelho and Pequiarana species through quantitative colorimetry using CIELAB color system. Such species come from a forest sustainable area of Thousand Precious Woods Company, located in Itacoatiara in the Amazon region of Brazil. Five wood samples from each species were selected so as to determine the following colorimetric parameters: L*, a*, b*, C e h*. In addition, 225 measurements were carried out with Konica Minolta CM-5 spectrophotometer connected to the computer. Results pointed out to statistical differences in the colorimetric parameters and also a low saturation in a* in the analyzed species. According to the cluster gathering, Breu-vermelho wood presents olive and/or grayish pink color, Tauari-vermelho is pinkish-gray and Pequiarana is grayish-pink and/or pinkish-gray. Such species presented differences in color among the three anatomic sections cited above and were also influenced by the yellow color defined in b* parameter. To summarize, colorimetric analysis to establish wood color is a simple procedure which may be used from the sawing of the logs until their final exploitation enabling value aggregation to the final product

Strenght of the glue line of edge glued panels of Pinus taeda made with different adhesives

The study compares the strength of the glue line of edge glued panels of Pinus taeda made with different industrial adhesives. Three types of adhesives (poly(vinyl) acetate (PVAc), emulsion polymer isocyanate (EPI) and polyurethane (PU)) glued in two side gluing orientation (radial and tangential) and analyzed after the conditioning tests (dry and wet) were analyzed. The 360 specimens were prepared for determining the shear strength of edge glued panels of Pinus taeda, and these were tested in a universal testing machine called EMIC. The shear strength of the glue line at dry condition was lower in the tangential side for the three types of adhesives analyzed. The PU adhesive showed the highest values of shear strength in the applied conditions, differing from PVAc and EPI adhesive when tested on dry condition and did not differ from the others adhesives when tested on wet condition. The highest percentage of wood failure was observed after the shear strength test at dry condition to EPI adhesive glued in the radial side. And in the wet condition, the EPI adhesive and PU adhesive glued in tangential side showed higher mean values of wood failure. Thus, it was possible to conclude that the strength of the glue line of Pinus taeda wood was influenced by the type of adhesive and side gluing orientation, and showed differently behavior according to the condition of use (wet or dry)