Effects of Alkaline Sulfite Anthraquinone and Methanol Pulping Conditions on the Mechanical and Optical Paper Properties of Bamboo (Gigantochloa scortechinii)

Abstract

The objective of this study was to evaluate the mechanical and optical properties of paper made from alkaline sulfite anthraquinone and methanol (ASAM) unbleached pulp from bamboo (Gigantochloa scortechinii). The bamboo pulps were beaten using a PFI mill at 10,000 revolutions. To determine the properties of unbleached bamboo ASAM paper, handsheets with a density of 60 g/m 2 were formed with 14 to 18% NaOH, 80/20 Na2SO3/ NaOH, 0.1% AQ, 0.5% EDTA, and 15% methanol pulping conditions. Pulping at 18% NaOH for 120 min cooking time produced paper with properties of 24.8 Nm/g and 43.02% for the tensile index and ISO brightness, respectively. Cooking at 16% sodium hydroxide for 90 min rendered the best results for mechanical and optical properties, with results of 20.86 Nm/g, 22.64 mN.m 2 /g, and 39.32% ISO value for the tensile, tear indices, and brightness, respectively. High quality bamboo paper produced by the ASAM pulping process was beneficial for producing highly durable paper and paperboard.

Alkaline Sulfite Anthraquinone and Methanol (ASAM) Pulping Process of Tropical Bamboo (Gigantochloa scortechinii)

“…More lignin is eliminated in the period of bulk delignification phase. This elimination occurs much more quickly than the third stage (residual delignification) [41,42]. As a result, the proportion of lignin removal in polysaccharides happens slowly.…”

“…Thus, this is only true when a sufficient amount of alkali charge is available. Thereupon, by adding AQ to the cooking liquid, more alkalinity can be stored for the bulk delignification volume and more lignin can be removed [38,42]. On the other hand, AQ has the role of an effective stabilizer in both wood and non-wood polysaccharides.…”

“…In comparison with kraft pulping process, the ASAM pulping process has a higher digester pressure of 1.3-1.4 MPa and the cooking temperature of 5-10 [42]. Several studies have considered the application of ASAM in the cooking process of both hard and soft wood.…”

“…Several studies have considered the application of ASAM in the cooking process of both hard and soft wood. Moradbak et al [42] reported that Eucalyptus globulus had been cooked by ASAM pulping process, which results in 56.9 and 53.6% pulp yield and 14 and 10 Kappa number, respectively. Pulp yield and Kappa number of Pinus sylvestris were found to be from 52.9 to 52.5% and from 31 to 27, respectively [52].…”

“…Previous studies have focused on either sodiumanthraquinone (Soda/AQ) pulping or alkaline sulfite-anthraquinone (AS/AQ) pulping. In pulping process, the parameters that are of most significance with respect to delignification and polysaccharide removal are alkali charge and cooking time [42,47]. In addition, ASAM pulping process has better selectivity in comparison to kraft or soda pulping processes in terms of delignification, which leads to low Kappa number and high viscosity.…”