Lignin containing micro and nano-fibrillated cellulose obtained by steam explosion: Comparative study between different processes.

The isolation of lignin containing micro- and nanofibrillated cellulose (L-MNFC) requires a multistep process. In this study, beech wood was pre-treated by steam explosion (SE), refined or pre-treated by 3 SE and grinded until gel formation. A conventional cooking in an autoclave (SC) was applied in order to get a control sample. The effect of bleaching of a SE pulp was also studied. The chemical composition of the pulps was assessed as well as fiber morphology to compare the effect of the different processes. Quality index and energy consumption during the production process were studied. Results showed that SE can replace SC for the production of pulps with higher lignin content: 8-12% wt. and 3% wt., respectively. Gels contain micro and nanofibrillated cellulose and residual fibers with a dispersion of lignin nanoparticles and some nanocrystals. Optimization of the ultrafine grinding step was required to minimize the energy consumption.
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