Nanofibrilation of alkali-pretreated cellulose fiber using grinding treatment

Abstract

Abstract The aim of this study is to explore the effect of strong alkali-pretreatment on manufacturing cellulose nanofibril s(CNFs) with mechanical (grinder) treatment. The structural change (from cellulose I to cellulose II) and sharply reduction in the yield of hemicellulose component (xylose) of cellulose fibers (bleached kraft pulp) were observed after strong NaOH (20 wt.%) pretreatment. However, the differences depending on treatment time (1 h or 2 h) were not significant. The subsequent mechanical (grinder) treatment did not lead to any significant changes in the chemical composition, specifically the sugar contents, of the cellulose fiber. Morphological analyses showed that generated micro- and nano-fibers in the suspension were gradually decreased with increasing mechanical pass number. Also, the mean width of the nanofibers produced from alkali-pretreated pulp was relatively thicker than those from untreated pulp. UV-transmittance and turbidity results showed that alkali pretreatment and subsequent mechanical treatment led to an increase in the nanofibril content. Therefore, alkali pretreatment and subsequent mechanical grinding provide a promising method for the efficient and cost-effective production of CNFs.