Amphiphilic Cellulose Nanocrystals from Acid-Free Oxidative Treatment: Physicochemical Characteristics and Use as an Oil-Water Stabilizer

摘要

A chemical pretreatment for producing cellulose nanocrystals (CNCs) with periodate oxidation and reductive aminatioh is reported. This new fiinctionalization of cellulose fibers dispenses an alternative method for fabricating individual CNCs without the widely used acid hydrolysis process. CNCs can be directly modified during the pretreatment,step, and no additional post-treatments are required to tune the surface properties. Three butyiamine isomers were tested to fabricate CNCs with amphiphilic features. After mechanical homogenization, CNCs occurred as individual crystallinities without aggregation where high uniformity in terms of shape and size was obtained. The elemental analysis and ~1HNMR measurement show that iso-and n-butylamine attach the highest number of butylamino groups to the cellulose fibers. Linking the alkyl groups increases the hydrophobic nature of the CNCs, where water contact angles from self-standing films up to 110.5° are reported. Since these burylamino-functionalized CNCs have hydrophobic characteristics in addition to the hydrophilic backbone of cellulose, the stabilization impact on oil/water emulsions is demonstrated as a potential application,