CHEMITHERMOMECHANICAL PULPING OF 2ND-GROWTH LODGEPOLE PINE FROM WESTERN CANADA

The properties of chemithermomechanical pulps (CTMP) from second-growt h lodgepole pine trees have been determined. The butt portions of each of 12 trees were separated into juvenile wood and mature wood compone nts for mechanical pulping, and for evaluation of pulp (fiber) and han dsheet properties. Juvenile wood required 20% more energy than did mat ure wood to refine to 130 mL CSF; Alberta samples required 14% more en ergy than did those from British Columbia to reach the same freeness l evel. CTMP pulp fibers from mature wood were generally longer than tho se from juvenile wood, but CTMP pulps from Alberta had fibers that wer e more flexible and finer than their British Columbia counterparts. Th us, the tensile and tearing strengths of mature wood pulps were usuall y, but not always, superior to those of juvenile wood pulps. Scatterin g coefficients of juvenile wood pulps at a freeness of 130 mL CSF were consistently higher than those of their corresponding mature wood pul ps because of their finer fibers.