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Most of the fibre raw materials used by the pulp and paper industry are from a small number of tree species. For instance, Eucalyptus and Pinus species are the major industrial pulpwood sources obtained from forests characterized by a relatively low biodiversity. The large monoculture areas also increase environmental risks such as those related to biotic attacks or forest fires. Diversification of industrial fibre sources has therefore been a matter of research and the characterization of different raw materials has been made in view of their pulping potential. Acacia melanoxylon R. Br. (blackwood) grows well in Portugal in pure or mixed stands with Pinus pinaster Aiton, and is valued as a timber species with potential for sawmills. In addition, the wood anatomical and chemical characteristics also allow to consider the species as an alternative raw material for the pulp industry. Acacia species, with their relatively short, flexible and collapsible fibres, have potential to produce papers with good trade-offs between light scattering/tensile strength and smoothness/tensile strength, at low energy consumption in refining. The pulping and paper making potential of blackwood has been studied by several authors showing an overall good pulping aptitude under the same experimental conditions of kraft pulping as used for eucalypt pulping with pulp yields ranging between 47 and 58 %. The presence of heartwood should be taken into account because it decreases the raw-material quality for pulping due to the higher extractives content. Heartwood proportion should therefore be considered as a quality variable when using A. melanoxylon wood in pulp industries. This chapter describes the characterization of the A. melanoxylon wood pulping performance, regarding yield and kappa number, and the pulp and paper properties. The application of fast spectroscopic technologies for pulp quality determination is also described. info:eu-repo/semantics/publishedVersion

Submitted by Margarida Galamba (galamba@isa.utl.pt) on 2013-02-25T14:02:38Z No. of bitstreams: 1 Estudo da aptidão da Acacia melanoxylon R. Br. para a produção de pasta e da aplicação de espectroscopia de infravermelho~1.pdf: 2303339 bytes, checksum: 4865094bdf4a60a38ea00139104e8aec (MD5) Made available in DSpace on 2013-02-25T14:02:52Z (GMT). No. of bitstreams: 1 Estudo da aptidão da Acacia melanoxylon R. Br. para a produção de pasta e da aplicação de espectroscopia de infravermelho~1.pdf: 2303339 bytes, checksum: 4865094bdf4a60a38ea00139104e8aec (MD5) Previous issue date: 2012 O presente trabalho foi realizado no âmbito do projecto nacional – Valorização do lenho de acácia produzido em Portugal. Potenciais utilizações (POCTI/42594/AGR/2001), e do projecto GEMINI - Genetic determination of maritime pine pulp and paper properties. Comissão das Comunidades Europeias, Projecto GEMINI – QLK5-CT-1999-00942. Bolsa de doutoramento (SFRH/BD/42073/2007) atribuída pela Fundação para a Ciência e Tecnologia (FCT) co-financiada pelo programa POCI 2010 – Formação Avançada para a Ciência – Medida IV.3 e pelo FSE.

In this work we study the behaviour in kraft cooking and papermaking of 6 Acacia melanoxylon wood chip samples, with basic densities of 449, 489, 493, 505, 514 and 616 kg/m3. The wood chip samples were screened and submitted to the kraft cooking process. Experiments were carried out with 1000-g o.d. of wood in a forced circulation digester. The cooked chips were disintegrated, screened and washed. The screened and total yields, kappa number and pulp viscosity were determined according to the standard methods. The morphological properties of pulp fibres were determined by image analysis of a diluted suspension in a flow chamber in Morfi®. The unbleached kraft pulps were submitted to a bleaching D0E1D1E2D2 sequence and their papermaking potential evaluated. The pulps were beaten in a PFI mill at 500, 2500 and 4500 revolutions under a refining intensity of 1.7 N/mm. Paper handsheets were prepared according to the Scan standard and tested regarding structural, mechanical and optical properties. Regarding the pulping potential, the pulp yield ranged between 47.7 and 57.7%. The selected wood samples provided bleached kraft pulps with markedly different biometrics characteristics. In fact, the mean values of fibre length, fibre width and coarseness ranged between 0.77 and 0.98 mm, 17.8 and 19.4 μm, 4.8 and 6.2 mg/100m, respectively. As expected, these biometrics characteristics have very high impact on paper structure, including smoothness, and on mechanical and optical properties, for the unbeaten pulps. At a given beaten level, the differences between pulps remain very high. Moreover, for a given paper density, tensile and tear strength, and light scattering coefficient are significantly different. To reach a given paper density, however, the different pulps required very different energy consumptions in beating.

Submitted by Ofélia Anjos (ofelia@ipcb.pt) on 2019-03-21T22:41:39Z No. of bitstreams: 1 2006_Papermaking potential of Acacia dealbata and Acacia melanoxylon.pdf: 160881 bytes, checksum: 4792e45ed6151dd4ecb3096a68ab42c0 (MD5) Approved for entry into archive by Maria Eduarda Pereira Rodrigues (erodrigues@ipcb.pt) on 2019-05-12T21:15:40Z (GMT) No. of bitstreams: 1 2006_Papermaking potential of Acacia dealbata and Acacia melanoxylon.pdf: 160881 bytes, checksum: 4792e45ed6151dd4ecb3096a68ab42c0 (MD5) Made available in DSpace on 2019-05-12T21:24:10Z (GMT). No. of bitstreams: 1 2006_Papermaking potential of Acacia dealbata and Acacia melanoxylon.pdf: 160881 bytes, checksum: 4792e45ed6151dd4ecb3096a68ab42c0 (MD5) Previous issue date: 2006 info:eu-repo/semantics/publishedVersion

The pulping and papermaking potential of Acacia dealbata and Acacia melanoxylon were studied using Eucalyptus globulus as a reference. Pulp yield, alkali consumption and delignification in the kraft process, of both species, compare very well with the reference. Pulp yield can be higher than that of E globulus and the residual lignin content lower after cooking, which is in good agreement with the lower lignin and extractives content of the wood samples used. Pulps produced from Acacia have slightly lower fibre length and coarseness and higher fibre width and wet fibre flexibility than E globulus pulps. As a consequence of fibre characteristics, the paper produced from Acacia is denser and exhibits higher tensile and burst strength, and lower tear resistance than that from E globulus, at a given PFI revolution. For the same sheet density E globulus displays higher strength properties, but the consequence of achieving this is a lower drainage rate and higher energy consumption in refining.

Submitted by Ofélia Anjos (ofelia@ipcb.pt) on 2019-03-18T17:55:37Z No. of bitstreams: 1 2011_Effect of Acacia Melanoxylon Fibre Morphology on Papermaking Potential.pdf: 160083 bytes, checksum: e6ee28bcacd30a5063ce65d5c8069c1e (MD5) Approved for entry into archive by Maria Eduarda Pereira Rodrigues (erodrigues@ipcb.pt) on 2019-04-15T09:49:45Z (GMT) No. of bitstreams: 1 2011_Effect of Acacia Melanoxylon Fibre Morphology on Papermaking Potential.pdf: 160083 bytes, checksum: e6ee28bcacd30a5063ce65d5c8069c1e (MD5) Made available in DSpace on 2019-04-15T09:55:42Z (GMT). No. of bitstreams: 1 2011_Effect of Acacia Melanoxylon Fibre Morphology on Papermaking Potential.pdf: 160083 bytes, checksum: e6ee28bcacd30a5063ce65d5c8069c1e (MD5) Previous issue date: 2011 info:eu-repo/semantics/publishedVersion

Submitted by Ofélia Anjos (ofelia@ipcb.pt) on 2019-03-21T22:46:58Z No. of bitstreams: 1 2008_Effect of Eucalyptus globulus wood density on papermaking potential.pdf: 296210 bytes, checksum: a9bb314c4f14523c9429723c8917b20f (MD5) Approved for entry into archive by Maria Eduarda Pereira Rodrigues (erodrigues@ipcb.pt) on 2019-05-12T21:15:49Z (GMT) No. of bitstreams: 1 2008_Effect of Eucalyptus globulus wood density on papermaking potential.pdf: 296210 bytes, checksum: a9bb314c4f14523c9429723c8917b20f (MD5) Made available in DSpace on 2019-05-12T21:25:13Z (GMT). No. of bitstreams: 1 2008_Effect of Eucalyptus globulus wood density on papermaking potential.pdf: 296210 bytes, checksum: a9bb314c4f14523c9429723c8917b20f (MD5) Previous issue date: 2008 info:eu-repo/semantics/publishedVersion

The wood of a mature (40-year-old) Eucalyptus globulus Labill tree was characterized at different stem height levels (0%, 10%, 35%, and 50% of total height) regarding pulping, bleaching, and paper properties. Pulp yields increased upwards from 46% to 50%, and Kappa number decreased from 17.5 to 12.3 at 0 and 50% height, respectively. The estimated specific wood consumption ranged from 3.2 m3 odt-1 to 3.1 m3 odt-1 at 0% and 50% height levels, respectively. Pulp drainage varied along the stem, with less drainability (20.3 oSR) and higher water retention value (1.07 g.g-1) at the base. Pulp fiber length increased (827 µm vs. 877 µm) and width decreased (19 µm vs. 17 µm) from 0% to 50% height levels. Tensile, tear, and internal bond strength decreased upwards, with mean values of 34.9 N.m.g-1, 3.1 mN.m2.g-1, and 95.8 J.m-2, respectively. These findings support the use of mature E. globulus trees without loss of pulp production and quality.