Author : Eav Suntha

Summary : The study was conducted to determine the properties and yield of dissolving pulps with different alpha-cellulose contents produced from Moluccan sau at different conditions of pulping and bleaching. These pulps were used to make rayon under different conditions.

A total of 1,296 specimens of rayon from different treatments were tested for tensile strength and elongation. The relative contributions of cellulose content of pulp, temperature of coagulating bath, cellulose solution concentration, immersion length and spinning rate to variation in tensile strength, were statistically analyzed.

Results showed that temperature had the highest effect in tensile strength, accounting for 13.3% of the total variance. This was followed by immersion length (4.2%), alpha-cellulose content (3.9%), and cellulose solution concentration (3.3%), and spinning rate (2.7%).

Chemical properties of the dissolving pulp from Moluccan sau were found comparable to those of commercial dissolving pulp in terms of alpha-cellulose, pentosan, other extract content, viscosity and degree of polymerization, but inferior in ash content and brightness.

The yield of bleached pulp, however, was only about 33% of that obtained from Benguet pine (Pinus kesiya Royle ex Gord.) Also, the tensile strength of the cuprammonium rayon produced in this study was only about 27% of that of commercial rayon.