Thermal and photochemical stability of poly(vinyl alcohol)/modified lignin blends

A kraft lignin derivative (KLD) obtained by reaction with p-aminobenzoic acid/phthalic anhydride was blended with poly(vinyl alcohol) (PVA) by solution casting from DMSO. PVA and PVA/KLD films were exposed to ultraviolet radiation (24, 48, and 96 h) and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (H-1 NMR) spectroscopy, and scanning electron microscopy (SEM). PVA films show a loss of thermal stability due to irradiation. PVA/KLD reveals greater thermal stability than PVA and an increase in thermal stability after irradiation. These results suggest that the incorporation of KLD into PVA provides a gain in thermal and photochemical stability. FTIR, H-1 NMR, DSC, and TG results obtained for the blends suggest that intermolecular interactions between PVA and KLD chains are present. SEM micrographs revealed blend miscibility for a KLD blend content of up to 15 wt%, as observed at magnification of 1000 times. (c) 2005 Elsevier Ltd. All rights reserved.

Economic and technical feasibility study of a combined-cycle cogeneration system associated with cellulose plants

In this paper, is presented an economical and technical feasibility study of a combined cycle cogeneration system proposed to be used in a pulp plant located in Brazil, where around 95% of country's pulp production is done by the use of Kraft Process. This process allows the use of black liquor and other by-products as fuel. This study is based upon actual data from a pulp plant with a daily production of 1000 tons., that generates part of the energy demanded by the process in a conventional cogeneration system with condensing steam turbine and two extractions. The addition of a gas turbine was studied to compare electricity production level and its related costs between original system and the new one, considering that the former can use industrial by-products and firewood as fuel, when required. Several parameters related to electric generation systems operation and production costs were studied. The use of natural gas in the combined cycle, in comparison with the use of firewood in the conventional system was studied. The advantages of natural gas fuel are highlighted. The surplus availability and the electricity generation costs are presented as a function of pulp and black liquor production.

Xylanase and β-Xylosidase from Penicillium janczewskii: Production, Physico-Chemical properties, and application of the crude extract to pulp biobleaching

Extracellular xylanase and β-xylosidase production by a Penicillium janczewskii strain were investigated in liquid cultures with xylan from oat spelts under different physical and chemical conditions. The selected conditions for optimized production of xylanase and β-xylosidase were 7 days, pH 6.5, at 30 °C and 8 days, pH 5.0, at 25 °C, respectively. The xylanase exhibited optimal activity in pH 5.0 at 50 °C and the β- xylosidase in pH 4.0 at 75 °C. The xylanase was more stable at pH 6.0 to 9.5, while the β-xylosidase remained stable at pH ranging from 1.6 to 5.5. The xylanase half-life (T50) at 40, 50, and 60 °C was 183, 15, and 3 min, respectively. β-xylosidase half-life was 144, 8, and 4 min at 50, 65, and 75 °C, respectively. When applied to the biobleaching of Eucalyptus kraft pulp, xylanase dosages of 2 and 4 U/g dried pulp reduced, respectively, kappa number by 3.0 and 3.3 units after 1 h treatment, demonstrating that the use of P. janczewskii xylanases in this process is quite promising. The pulp viscosity was not altered, confirming the absence of cellulolytic enzymes in the fungal extract.

Avaliação fitoquímica e microbiológica da espécie Artemisia annua L., submetida a tratamentos de armazenamento e condições de ambiente

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Tolerância à dissecação e armazenamento de sementes de Araticum-de-terra-fria (Annona emarginata) (SCHLTDL.) H. Rainer)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aproveitamento de resíduos da indústria de celulose e papel em argamassa mista de revestimento interno

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo da madeira e polpação de Eucalyptus urophylla e do híbrido E. urophylla x E. grandis em dois modelos silviculturais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características morfológicas de celuloses branqueadas de pinus e eucalyptus em analisador óptico automático de fibras

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dimensões de cavacos industriais de eucalipto e relações com polpação, resistência e morfologia de fibras na polpa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de resíduos agronômicos da mandioca para fabricação de papéis especiais como recurso alternativo para a comunicação visual

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Preparado biodinâmico, épocas de colheita, temperaturas de secagem, tempo de armazenamento e tipos de embalagem na produção e conservação de alecrim (Rosmarinus offinalis L.)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Xilanases, ß-xilosidases de Penicillium janczewskii: purificação, caracterização e aplicação no branqueamento da polpa celulósica e para ração animal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Qualidade fisiológica e armazenamento de sementes de ipê-verde (Cybistax antisyphilitica (Mart.) Mart.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tall oil e seus subprodutos: alternativas como preservantes para madeira

Pós-graduação em Engenharia Mecânica - FEG

Viabilidade e longevidade de sementes de tabebuia aurea benth. & hook. submetidas a diferentes métodos de armazenamento

Seeds Tabebuia aurea (syn. Handroanthus aureus Mattos), The seeds of Tabebuia aurea (syn. Handroanthus Mattos aureus), have low metabolic rates, which favors their storage conditions and freezing temperatures when stored at room temperature, there is a progressive decline in viability. Therefore, this study aims to determine the viability and longevity of seeds of Tabebuia aurea subjected to different storage methods. There were used 6100 seeds. In 2400 seeds were stored refrigerator, which in 1200 placed in transparent plastic bag and 1200 in Kraft paper bags. 3600 Other seeds were placed in room temperature and 1200 seeds in clear plastic bag, 1200 in Kraft paper bags and tray open in 1200. For each treatment, four replicates of 25 seeds for 12 months, with design was completely randomized. The average germination, normal seedlings and speed germination index were transformed into (x+1)(-1/2). The data were submitted to ANOVA and means compared by Tukey test at 5%. Also regressions polynomials were modeled for the variables study in function of the periods of storage of the seeds. The seeds stored in the refrigerator at 13 C maintained a high germination rate and normal seedling germination rate during the 360 days of evaluation. The method suitable for the seed storage of Tabebuia aurea is in the refrigerator at 13 degrees C, both in plastic and paper.