Teores de lignina e ácidos urônicos na madeira e polpa celulósica de Eucalipto

Abstract

RESUMO -O teor de lignina influencia a alvura da polpa celulósica e, por isto, é uma variável importante no processo de sua fabricação, o que torna fundamental estabelecer métodos para determinar seu valor. Baseado na hipótese de que os métodos disponíveis para avaliar o teor de lignina solúvel medem, também, os ácidos urônicos na madeira, isto tornaria este método impreciso. O objetivo desse trabalho foi verificar se existe correlação entre a lignina e ácidos urônicos na madeira de eucalipto e na polpa celulósica. Quarenta e seis amostras, sendo 24 amostras de madeira, 11 de polpa não branqueada e 11 de polpa branqueada foram utilizadas para se determinar os teores de lignina e de ácidos urônicos. As amostras de madeira apresentaram maior quantidade de lignina e, por isto, os teores de ácidos urônicos não influenciaram de forma significativa os valores da mesma. Amostras de polpa celulósica, com menor quantidade de lignina, mostraram grande correlação entre os valores de ácidos urônicos e lignina. Os testes de medição de lignina na polpa celulósica apresentaram baixa precisão. CORRELATION BETWEEN LEVELS OF LIGNIN AND URONIC ACIDS IN THE WOOD AND CELULOSE PULP OF EUCALYPTUS ABSTRACT -The lignin content influences the cellulosic pulp brightness and therefore is an important variable in the manufacturing process, making it essential to establish methods to determine its value. Based on the

Cellulose pulp produced from bulrush fiber

“…According to ZANUNCIO & COLODETTE (2011), the eucalyptus wood samples contained 4.05% to 5.29% uronic acid in the samples. Therefore, the value of uronic acid occurring in the reed samples was lower than that in eucalyptus wood.…”

“…As the hexenuronic acids are not favorable to the cellulosic pulp bleaching process because they utilize reagents like chlorine, chlorine dioxide, ozone or peracids used in this process (ZANUNCIO & COLODETTE, 2011), their presence makes the reed pulp unsuitable for bleaching.…”

Determination of the Chemical Composition of Eucalyptus spp. for Cellulosic Pulp Production

“…The growing demand for cellulose pulp and paper requires a high-quality raw material, stimulating the control of the production chain and the selection of potential clones with high yields of cellulosic pulp, based mainly on productivity and wood quality [15,16]. However, specific characteristics important for further pulp and paper production are usually disregarded in tree breeding programs.…”

EFFECT OF THE LOG STORAGE OF Pinus taeda L. ON THE QUALITY OF KRAFT PULP

“…The cellulose pulp was analyzed to determine the insoluble lignin content, and the filtrate was collected and enlarged to 250mL and segregated to determine the soluble lignin content. This property was determined by spectrophotometry with readings at wavelengths of 215 and 280nm, as proposed by Zanuncio and Colodette (2011). The monosaccharide content was determined according to the method described by Wallis et al (1996), and used in a Dionex ICS 5000 ion chromatography system.…”