Assessment of Tropical Pines for Pulping and Paper Making Characteristics

Pinus greggii, P. psudostrobus, P. montezume,& P. taeddi of young age (8-10 years) were pulped using 14%, 16% &18% active alkali, 25% sulphidity at about 1906 H factor to assess pulping and papermaking characterstics. It was observed that kraft pulps of these tropical pine species do not have any appreciable difference in physical strength properties of handsheets. All the pulps produced were in the range of burst index, 4.35 ± 0.75; tensile index, 61.65 ± 9.65; tear index. 7.89 ± 0.74 at freeness 300 ml CSF. Total pulp yield and kappa number decreased with the increase in active alkali charge, as expected Comparatively lower tear index in all the cases could be attributed to the young age of the wood samples, used. However, at burst index 3.0 and tensile index 40.0, the tear index was found to be above 10.0. Slight dlfference in physical strength properties at different chemical charge within the species and among the species was observed. It was observed that their was no appreciable improvement in physical strength properties of unbleached pulps on increasing the alkali charge (at least over 16% alkali charge at freeness 300 ml CSF), except decrease in kappa number, under the conditions studied. Therefore, it could be concluded that for unbleached grade pulps, 16% active alkali would be suitable. However, 18% active Alkali would be more suitable to produce easy bleachable pulps of lower kappa number (⋍ 35). Proximate chemical analysis and fibre dimension analysis have been carried out and recorded in the paper. These have also been correlated with the pulping and papermaking characteristics of individual sample. A comprehensive review on the work done by various workers at this institute on the pulping and papermaklng characteristics of some of the indigenous and exotic pine species have also been included in the paper for comparison.