Partial exchange of ozone by electron beam irradiation shows better viscosity control and less oxidation in cellulose upgrade scenarios

Electron beam irradiation (EBI) is an alternative treatment for intrinsic viscosity (IV) control in cellulose pulps, but has never been integrated in full bleaching sequences for comparison to conventional methods. Both eucalyptus kraft (EK) paper pulp and beech sulfite (BS) dissolving pulp were subjected to totally chlorine free (TCF) bleaching sequences comprising either EBI, ozone, or both for IV control. Additionally, effects of EBI on hexenuronic acid (HexA) and xylan were investigated. IV was adjusted to 450–500 mL g−1 and properties including carbonyl content, kappa, brightness, alkali-resistance and sugar composition were compared. Pulps produced with EBI had a higher alkali-resistance, uniformity and less cellulose oxidation. However, the degree of bleaching (DoB) was low without the use of ozone. HexA content in a birch pulp was halved by EBI. Isolated xylans were more resistant to irradiation than cellulose with little decrease of molar masses and moderate oxidation.