Evaluation of pre-hydrolyzed soda-aq dissolving pulp from populus deltoides using an oded bleaching sequence

Abstract

In the present work, the production of dissolving pulp from fast growing 30-year-old local plantation aspen was investigated. The mill-made chips of aspen (Populus deltoides) after being pre-hydrolyzed with water at 170 °C, were pulped with a soda-AQ pulping process at a kappa number of 15. It was further delignified to a kappa number of 9.2 using a single stage oxygen delignification and bleached with a D0ED1 bleaching sequence at different kappa factor. The pulp viscosity was increased at higher brightness and similar α-cellulose when the kappa factor was increased from 0.30 to 0.45 in the D0 stage of the D0ED1 bleaching sequence, due to higher lignin dissolution and more fiber purification. The results showed that pre-hydrolyzed soda-AQ dissolving pulp can be made from Populus deltoides at a high level of alpha-cellulose content and acceptable levels of brightness and viscosity by means of proper control and optimization of pre-hydrolysis, pulping, and oxygen pretreatment conditions, and an optimized DED bleaching sequence.