3.2.5. Reactivity of ASAM pulping

A review of the reactivity of alkaline sulfite anthraquinone and methanol (ASAM) pulping process shows that the information available is relatively scarce, fragmented and yet to gain adequate commercial applications. 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. Few studies have


The tear, tensile and burst indices of unbleached bamboo ASAM paper were within the range

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

suitable for packaging paper. The study revealed that the optimum ASAM pulping parameters were at 16% NaOH and 90 min cooking time, resulting in paper having tensile index of

pulping process is to produce pulp with a low proportion of rejected material. Aldonic acid, which is present as a result of isolation from pulp hydrolyzates, indicates that stabilization takes place through conversion of the end group to the acid out of an oxidation reaction [42, 60]. Therefore, according to role of AQ and methanol in ASAM pulping process, one can

The study determined the technical feasibility of bamboo culms (G. scortechinii) as a non-wood fiber for pulp and paper industry. For this purpose, the biometric characteristics and chemical compositions, pulping characteristics, paper properties, projects ASAM pulped of G. scortechinii as good material for pulp and paper packaging material. The results show that the fiber length of G. scortechinii is similar to softwood and had significant effects on the properties of bamboo paper. The Runkel and flexibility ratios of G. scortechinii were in the range of spruce (softwood) with 0.86 and 50.14, respectively. Meanwhile, the chemical composition analysis of G. scortechinii presented that bamboo have a high amount of cellulose content and lowest solvent extractive content in comparison with other non-wood species. Therefore, the result showed that G. scortechinii can produce pulp and paper, which is almost comparable to other sources. It was also found that the pulp properties of bamboo often being subjected to ASAM pulping process were significantly affected (at p ≤ 0.05) by the cooking conditions. The pulp at 18% NaOH and 90 min cooking time gave low pulp yield and the tear

and 90 min cooking time presented the best properties, pulp yield, Kappa number, tensile, tear

The authors are thankful to the Institute of Tropical Forestry and Forest Products (INTROP), Universiti Putra Malaysia (UPM), and the Higher Institution Centre of Excellence (HICoE) Ministry of Higher Education Malaysia, Grant No. 6369107. Additional thanks are extended to the School of Industrial Technology, Universiti Sains Malaysia (USM) and the Federal

and burst indices with values of 49.06%, 14.2, 20.86 Nm/g, 22 mN.m2

Institute of Industrial Research Oshoidi Nigeria for technical support.

/g, respectively, which is

19

http://dx.doi.org/10.5772/intechopen.76806

/g and brightness of 39.32%. Another advantage of this

/g, respectively. The pulp made at 16% NaOH

/g and 10.05 kPa.m2

/g,

/g, 24.8–17.87 Nm/g and 10.83–9.27 kPa.m2

of 26.33–18.64 mN.m2

4. Conclusion

respectively.

Acknowledgements

20.86 Nm/g, tear index of 22.64 mN.m2

expect high yields of ASAM bamboo unbleached pulp.

index with values of 41.24% and 18.64 mN.m<sup>2</sup>

AQ = anthraquinone, T = time, Temp = temperature.

Table 5. Effects of ASAM pulping parameters on pulp and paper properties of various types of lignocellulosic materials.

considered the application of ASAM in the cooking process of both hard and soft wood. Table 5 gives the summary of the reported pulping of lignocellulose biomass using ASAM pulping process on different lignocellulose biomass compared with the ASAM pulped bamboo (G. scortechinii) species. At a constant ASAM pulping process at 170 and alkali ratio (Na2SO3/ NaOH; anthraquinone: methanol) of (80/20, 0.1%: 15%), it was found that ASAM pulped bamboo gave a characteristic high yield of 52.36%. Like the other ASAM pulped biomass (Table 5) this is quite higher than what is obtainable in kraft pulping. The highest yield was achieved by applying 14% sodium hydroxide and 90 min cooking time while the lowest Kappa number (10.38) was observed using 18% and 120 min. Further increase of both alkali and cooking time resulted in marked decrease in both Kappa number and pulp yield. From the result, ASAM pulping of bamboo (G. scortechinii) revealed a low Kappa number compared with what was obtained from Hibiscus cannabinus, whole jute plant, Eucalyptus globulus and Eucalyptus globulus labill as reported by Khristova et al. [54]; Jahan et al. [55]; Kordsachia et al. [56]; and Gominho et al. [58], respectively, despite the high ASAM pulping parameters used.

The tear, tensile and burst indices of unbleached bamboo ASAM paper were within the range of 26.33–18.64 mN.m2 /g, 24.8–17.87 Nm/g and 10.83–9.27 kPa.m2 /g, respectively, which is suitable for packaging paper. The study revealed that the optimum ASAM pulping parameters were at 16% NaOH and 90 min cooking time, resulting in paper having tensile index of 20.86 Nm/g, tear index of 22.64 mN.m2 /g and brightness of 39.32%. Another advantage of this pulping process is to produce pulp with a low proportion of rejected material. Aldonic acid, which is present as a result of isolation from pulp hydrolyzates, indicates that stabilization takes place through conversion of the end group to the acid out of an oxidation reaction [42, 60]. Therefore, according to role of AQ and methanol in ASAM pulping process, one can expect high yields of ASAM bamboo unbleached pulp.
