Chiang Mai Journal of Science

Sweet bamboo chips were pulped by using alkaline sulfite pulping (AS), alkaline sulfite pulping with anthraquinone (AS-AQ) and conventional kraft pulping was used as reference. In the case of AS pulping was modified by adding 0.1 % anthraquinone (AQ) in to AS cooking liquor for compared delignification rate, screened yield and unbleached pulp properties. Considering the AS-AQ pulping process found that the addition of 0.1% AQ can raised the delignification rate which indicated by kappa number and pulping yield. The AS and AS-AQ screened yields were approximately about 10% higher than kraft screened yield but AS-AQ and kraft kappa numbers were averaged about 18 points lower than AS kappa number. The AS and AS-AQ kappa numbers presented AS pulp had higher kappa number than ASAQ pulped about 19 points. At the similar kappa number of about 12.5 points, kraft pulping had lower pulping yield than AS-AQ pulp yield about 9.2%. They were 46.3% and 55.6% respectively. After that unbleached kraft and AS-AQ pulps were refined by PFI mill for pulp properties testing. The result indicated unbleached AS-AQ pulp and it required higher energy consumption for beating than unbleached kraft pulp about 1000 revs. The mechanical strength properties of unbleached AS-AQ pulp were lower than those of unbleached kraft pulp. The highest mechanical strength properties of unbleached kraft pulp such as tensile, tear, burst strength and folding endurance, which were 70.2 Nm/g, 35.8 mN.m²/g, 4.1 kPa.m²/g and 492, respectively.