Carboxyethyl reaction was used as a pretreatment method before grinding and homogenization to prepare microfibrillated cellulose (MFC). The effect of carboxyethylation on the properties of cellulose materials and prepared MFC samples were investigated. Results showed that cellulose materials with different carboxyethyl content were obtained by controlling the chemical dosage. This reaction increased the water retention value, decreased the degree of polymerization and crystallinity, and changed the crystalline structure of cellulose. After pretreatment, the cellulose fibers were easier to be swelled and fibrillated, which greatly reduces the frequency of grinding. In addition, the diameter of the produced MFC decreased with the increase of carboxyl content. The charge density, suspension stability and transparency of MFC increased obviously due to the presence of carboxyethyl groups. This study provides a comprehensive understanding of carboxyethyl pretreatment for the preparation of MFC, which may help to enrich and promote the preparation and application of MFC.
Keywords: Carboxyethylated pretreatment; Carboxyl content; Mechanical fibrillation; Microfibrillated cellulose.
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