Banana Wastes as a Source of Lignocellulosic Fibres For Papermaking

  • R. Noronha (University of Madeira, Department of Chemistry, Portugal) ;
  • N. Cordeiro (University of Madeira, Department of Chemistry, Portugal) ;
  • M. N. Belgacem (University of Beira Interior, Department of Science and Technology fo Paper, Protugal) ;
  • A. P. Costa (University of Beira Interior, Department of Science and Technology fo Paper, Protugal) ;
  • J. Silvy (University of Beira Interior, Department of Science and Technology fo Paper, Protugal)
  • Published : 1999.04.01

Abstract

The chemical composition of crops from banana (Musaaccuminata Colla) was studied. Two types of material were investigated, namely: the whole material (type I) and the outer bark material (type II), which was apparently rich in cellulose fibres. These characterisation showed that the amount of holocellulose is high enough (∼70%) to envisage the pulping of this material, despite its surprisingly high content of ashes (∼14%). It is worth noting that, as expected, the type II material was found more rich in cellulose. Soda and Soda-Anthraquinone cooking processes were carried out using mini-digestors and the optimal pulping conditions were established. In fact, it was found that the maximum of yield is obtained when the following pulping conditions are respected: alcali 18%, time of the reaction: 1 hour to reach the isothermal regime and 30 min of pulping at 120$^{\circ}C$. The kappa number of these pulps was found around 30, which is very acceptable for unbleached pulps. The use of anthraquinone was found to increase the yield of pulps very slightly. The morphology of the fibers thus obtained was determined and showed that about 80% of fibres have a length between 1.4 and 1.9 ${\mu}$m. The width of these fibres was also determined and found in the range of 10-30 ${\mu}$m. Finally, hand sheet paper with two basis weight (60 and 135 g/㎡) were made from pulps using the optimal conditions of cooking (300 g OD of crops). The yield and the kappa number of this cooking were very close to those found in mini-digestor reactions. The unbeaten pulps had a relatively high Shopper degree (59$^{\circ}$SR) and the drainage was slow when the paper sheets were made. These papers showed good physical mechanical properties. The high basis weight was submitted to test which are specific to corrugated boards and showed very interesting values of RCT, CMT and FCT.

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