| Abstract:In order to evaluate the optimal rotation age of Larix kaempferi pulpwood, the chemical composition, fiber morphology, and pulpability of Larix kaempferi pulpwood with different rotation age were analyzed. Specifically, the pulpability was investigated by testing the physical strength of handsheets made from different rotation ages´ Larix kaempferi pulpwoods in the same cooking conditions. The study showed that the 17-year-old Larix kaempferi was much more applicable for pulping under the same pulping conditions(20% alkali charge (Na2O);sulfidity was 25%; liquid-to-wood ratio was 1∶4; the maximum temperature was 170℃; the heating up time was 90 min; the time at maximum temperature was 150 min; the beating degree was 45°SR）.Particularly, the fiber properties of 17-year-old Larix kaempferi were listed as below: length-to-width ratio 77.66, ratio of cell wall to cavity 1.11, coarseness 0.188 mg/m.The properties of the pulp were as below:yield of screened pulp 42.9%, Kappa number 25.9, and cooking residual alkali 8.14 g/L; the physical strength of handsheets were also listed as below: tensile index 81.4 N·m/g, burst index 6.71 kPa·m2/g, tearing index 13.7 mN·m2/g, and folding endurance 294 times. |
