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Context: In Uruguay, numerous Pinus taeda plantations are at final-turn age, but they still do not have commercial destination and are exported as green-wood logs. For the development of this sector, it is necessary to strive towards a comprehensive processing of this resource. Method: This work focused on analyzing the use of Pinus taeda wood available in the country to produce brown kraft pulp with a kappa number of 80, which can be used to make packaging paper. As raw materials, we employed by-products from the mechanical wood-transformation industry (wood chips and thinning wood) and final-turn wood. Pulping tests were carried out, varying the alkali charge and the H-factor while aiming for a kappa number of 80. The viscosity, pulping, and rejection yield were measured in the pulps, and the pH and residual alkali content were evaluated in black liquor. Results: Based on the results, the best pulping conditions were an active alkali charge of 14% (Na2O) and an H-factor of 1260 for sawmill chips and thinning wood, as well as an active alkali charge of 14% (Na2O) and an H-factor of 1080 for final-turn wood. The pulp obtained with sawmill chips exhibited the most resistant fibers, and the final-turn wood pulp was the most sensitive to the refining process. Under the aforementioned conditions, the paper properties of laboratory-produced pulp are comparable with those of commercial pulp. Conclusions: This indicates that it is technologically possible to produce brown kraft pulp from Uruguayan Pinus taeda wood, with adequate quality to produce packaging paper

Inorganic fillers are usually used in papermaking industry to reduce production costs and enhance paper optical properties. As an attempt to improve fillers application in papermaking, carboxymethyl cellulose (CMC) and poly aluminum chloride (PAC) were used to encapsulate precipitated calcium carbonate (PCC) filler and modify its surfaces. In the first step, the optimum conditions for filler treatment (i.e. pH, CMC and PAC contents) were obtained. Through the second step, different amounts of CMC-encapsulated PCC were added to fiber suspension and some hand-sheets were made. Then, the effect of modified filler addition in different levels of 20, 25, and 35% on mechanical and optical properties of paper was investigated. The PAC dosage was found to be a critical factor for effective encapsulation of PCC fillers by carboxymethyl cellulose. When the dosages of CMC and PAC were 4% and 0.8% (based on the dry weight of PCC), respectively, filler modification caused to improve significantly the retention by more than twice. Strength properties of the hand-sheets fabricated with the CMC/PAC-modified PCC were also found to be significantly better than those obtained with the unmodified PCC at similar levels of filler content. In addition, the brightness and opacity of the filled papers at 30% addition of CMC-modified fillers were strikingly enhanced to 88.45 and 77%, respectively. SEM observations of the filled papers also demonstrated that CMC-encapsulated filler particles were clustered and retained efficiently onto the fiber network. The present method for modification of PCC may provide an alternative approach to increase the filler amount in the paper structure by alleviating filler drawbacks.

In present study, single and consecutive applications of xylanase and lignin peroxidase were performed in an XOQP TCF sequence to bleach pine and eucalypts kraft pulp. The consecutive use of Geobacillus sp. strain 71 xylanase and Rhodococcus jostii RHA1 lignin peroxidase was more effective than the single uses. XyzGeo71 treatment (X) indicates a 9.76% and 28.52% reduction in kappa number for pine and eucalypts kraft pulps, respectively. LiPRHA1 treatment (X) showed a 7.88% and 20.9% reduction a in kappa number for pine and eucalypts kraft pulps, respectively. The consecutive treatment of XyzGeo71 and LiPRHA1 (X), however, indicated a 13.67% and 37.2% reduction in kappa number for pine and eucalypts kraft pulps, respectively. The results showed that delignification with the consecutive xylanase and lignin peroxidase treatment was very significant.

There is still a need to improve the production sequences of micro fibrillated and nano fibrillated celluloses to obtain more economic and better quality products. The aim of this study was to improve the production efficiency and quality of micro fibrillated and nano fibrillated celluloses by examining the enzyme (xylanase endo-1,4-) employed in pretreatment sequences. Fairly homogeneous nano fibrillated cellulose with a width of 35 ± 12 nm was produced in this study. Sequences employed to produce micro fibrillated and nano fibrillated celluloses decreased the cellulose crystallinity of bleached kraft pulp and lower total crystalline index and lateral order index values were observed for micro fibrillated and nano fibrillated celluloses in FTIR examinations. Lower crystallinities were also defined by 13C-NMR (46.2 ppm), which was substantiated with C6 peaks in the amorphous domain. Sequences to produce micro fibrillated and nano fibrillated celluloses resulted in shorter fiber dimensions with less ordered cellulose structure leading lower thermal degradation that reveal main polymer chain source from cellulose units. Dynamic mechanical thermal analysis results showed that the initial and maximum storage modulus of the nano fibrillated and micro fibrillated celluloses films were improved by 114% and 101%, respectively. The storage modulus of micro fibrillated and nano fibrillated celluloses films were 4.96 GPa and 2.66 GPa at temperature of 235°C, respectively.

Two common Nigerian-grown biomasses, gmelina (Gmelina arborea) and bamboo (Bambusaa vulgaris) have been pulped and their fibre characteristics and paper properties examined. The results of their chemical compositions showed some fair similarities. The amount of glucose in the pulps of both biomasses indicated their suitability as lignocellulosic materials for pulping. Their pulp yield ranged between 48,0-54,1%, which fell within the acceptable range for good pulpwoods. The analysis of their fibre dimensions revealed that bamboo fibre has a wider fibre length distribution and higher fine length content. Gmelina and bamboo had weighted mean fibre lengths of 0,93 and 2,07 mm and mean fibre widths of 24,1 and 16,9 μm, respectively. The Runkel ratios of the samples were 0,4 (gmelina) and 0,9 (bamboo): this is indicative of their suitability for paper making. Mechanical properties of handsheets obtained from gmelina compared fairly well with South African pulpwoods (Eucalyptus grandis and Pinus paluta). Bamboo exhibited better tear index values than these woods but with lower sheet density and tensile index. These properties were significantly improved in handsheets obtained from blends of gmelina and bamboo, raising the prospect of producing paper from blends of both raw materials in Nigeria.

O objetivo deste estudo foi desenvolver modelos de calibração multivariada, com espectros infravermelhos próximos (NIR), para predição de qualidade da madeira e da polpa celulósica kraft de Eucalyptus. Foram utilizadas 30 amostras de madeira, em forma de cavacos, e 116 amostras de polpa kraft de Eucalyptus. Os cavacos foram utilizados com dois teores de umidade (33% e 10%). Nos cavacos mais úmidos, foram obtidas as seguintes correlações: 97% na densidade básica, 84% no teor de extrativos e 93% no teor de lignina. Nos cavacos mais secos, as correlações foram: 97% na densidade básica, 92% no teor de extrativos e 90% na lignina. Para a predição de qualidade das polpas, foram obtidos espectros NIR de folhas de celulose e das polpas na forma original (desagregada). Os modelos com espectros obtidos na folha de celulose apresentaram correlações de 94% no número kappa, 93% na viscosidade da polpa, 90% no rendimento depurado e 86% no teor de ácido hexenurônico. Os modelos com espectros obtidos na polpa desagregada apresentaram as seguintes correlações: 90% no número kappa, 91% na viscosidade da polpa, 88% no rendimento depurado e 85% no teor de ácidos hexenurônicos. Os resultados demonstraram a viabilidade da aplicação da técnica de modelagem das características da madeira e da polpa celulósica, utilizando-se espectros NIR.The objective of this study was to establish mathematical calibration models for near infrared spectra (NIRS) to predict wood quality and kraft pulp characteristics for Eucalyptus. Two different wood chip moisture contents were used (33% and 10%) and 116 kraft pulp samples were measured (kappa number 13-18). For more humid chips, the following correlations were established: 97% for wood basic density, 84% for extractive content and 93% for lignin content. For drier chips, the correlations were: 97% for wood basic density, 92% for extractive content and 90% for lignin content. For pulp quality prediction, NIRS spectra were obtained from handsheets and from the pulp in the original form (disaggregated). NIRS models for handsheets presented 94% correlation for kappa number, 93% for pulp viscosity, 90% for screened yield and 86% for hexenuronic acid content. Models for disaggregated pulp presented the following correlations: 90% for kappa number, 91% for pulp viscosity, 88% for screened yield and 85% for hexenuronic acid content. These results demonstrate the viability and precision of the NIRS technique to estimate wood quality and pulp characteristics.

The use of 12-year-old Pinus tecunumanii (Eguiluz e Perry) grown in Colombia was evaluated for bleached kraft pulp production. Kraft pulps of kappa number 30 ± 1 were produced, and oxygen delignified and bleached to 90% ISO with ECF processes. The bleached pulps produced under optimum conditions were evaluated with regard to their strength properties. Pinus tecunumanii wood required low effective alkali charge to reach the desired kappa number and the unbleached pulp showed high oxygen delignification efficiency and bleachability when a OD(EO)DED sequence was used. The bleached pulps presented good physical-mechanical properties, which are comparable to those obtained with more traditional pines such as Pinus taeda and Pinus radiata. The results demonstrate that this tropical pine species is a suitable raw material for bleached kraft pulp productionForam avaliadas amostras de Pinus tecunumanii de (Eguiluz e Perry) com 12 anos de idade procedente da Colômbia, para produção de polpa de kraft branqueada. Produziram-se polpas kraft com número kappa 30±1, deslignificada com oxigênio e branqueada a 90% ISO por processo ECF. As polpas branqueadas foram produzidas em condições ótimas e avaliadas com relação às suas propriedades de resistência. A madeira de Pinus tecunumanii exigiu baixa carga de álcali efetivo para alcançar o número kappa desejado, e a polpa marrom mostrou eficiência na deslignificação com oxigênio e alta branqueabilidade quando submetida à seqüência OD(EO)DED. As polpas branqueadas apresentaram boas propriedades físico-mecânicas, em comparação com aquelas obtidas das espécies tradicionais de Pinus, como o Pinus taeda e o Pinus radiata. Os resultados indicaram que essa espécie de pinus tropical é uma matéria-prima satisfatória para produção de polpa de kraft branqueada.

Foram analisados clones de Eucalyptus de última geração, pertencentes às principais empresas brasileiras de celulose. Os estudos consistiram numa caracterização tecnológica detalhada da qualidade das madeiras utilizadas no processamento fabril das empresas. Foram realizadas análise químicas detalhadas das madeiras e cozimentos kraft, simulando-se uma das modernas técnica de digestor contínuo. Os resultados indicaram a alta qualidade dos clones de Eucalyptus atualmente plantados no Brasil para produção de celulose.Last generation of Eucalyptus clones pulped by the main Brazilian kraft pulp mills were used for this study. Detailed chemical analysis of the woods were carried out to establish the wood quality. Laboratory simulation of a modern continuous digester technique was used for pulp production. Results demonstrated the high quality of Eucalyptus clones wood that are being planted in Brazil for kraft pulp production.

Este trabalho objetivou classificar e selecionar clones de Eucalyptus sp, tendo em vista a qualidade das polpas kraft obtidas a partir de cada material. Os clones foram classificados quanto a rendimento depurado, viscosidade da polpa e álcali ativo usado no processo de polpação. A classificação dos clones foi realizada por meio da análise de agrupamento, utilizando-se o método de otimização de Tocher. A análise de agrupamento permitiu a separação dos clones em cinco grupos distintos, sendo encontrados grupos de clones com alto, médio e baixo potenciais para produção de polpa celulósica. As características que mais contribuíram para a divergência foram o rendimento depurado (58,1%) e a viscosidade da polpa celulósica (35,0%). Em geral, nos clones avaliados foram verificadas grandes variações com relação aos parâmetros estudados.The objectives of this study were to classify and select clones of Eucalyptus sp, aiming at pulp quality improvement. The clones were classified according to the screened yield, pulp viscosity and active alkali used for pulping. Classification of the clones was achieved by cluster analysis using the Tocher method. The clones were classified in groups having high, medium and low potential for pulp production. The results showed that the parameter that most contributed to group the different Eucalyptus sp clones was the screened yield (58,1%), followed by pulp viscosity (35,0%). In general, large variation was observed for the parameters evaluated.

Estudou-se uma nova técnica laboratorial de análise de qualidade da madeira de Eucalyptus sp. para produção de polpa celulósica kraft. A técnica consiste em realizar, simultaneamente, quatro cozimentos de cavacos utilizando diferentes cargas de álcali ativo para estabelecer a característica de deslignificação da madeira. Pelo uso de equações de regressão, calcula-se o álcali ativo necessário para obter o número kappa desejado, o rendimento, a viscosidade e álcali consumido para o kappa objetivo. Os estudos estatísticos evidenciaram que uma única batelada de quatro cozimentos é suficiente, não sendo necessário realizar repetições.A new laboratory technique was tested to determine Eucalyptus sp. wood quality for kraft pulp production. This technique consists in performing four cooks simultaneously using different active alkali charges to establish the wood delignification characteristics. Based on regression equation it is possible to determine the alkali charge necessary to obtain a desired kappa number and the yield, viscosity and the alkali consumed for the target kappa. Statistical analysis demonstrated that a set of four cooks without replication is sufficient to determine the wood quality characteristics.