Combined mechanical and enzymatic treatments for improving the Fock reactivity of hardwood kraft-based dissolving pulp

The cellulose reactivity is a key parameter in the viscose rayon production process. To increase the reactivity of hardwood kraft-based dissolving pulp, a combined mechanical refining and enzymatic treatment was applied based on the hypothesis that a mechanical pretreatment can enhance the subsequent enzymatic treatment efficiency. Compared with the control sample, increases in the fiber specific surface area and fines content of dissolving pulp by 66 and 10 %, respectively, were achieved because of the fiber fibrillation induced by PFI refining, which led to increased accessibility and thus enzymatic hydrolysis efficiency in the following cellulase treatment. As a result, the Fock reactivity by following the combined mechanical and enzymatic treatment was further enhanced, from 76 to 82 % compared with enzymatic treatment only. The effects of combined mechanical and enzymatic treatments on other properties of the dissolving pulp, for example, intrinsic viscosity and molecular weight, were also determined.