원문정보
초록
영어
Surface modification of cellulose nanocrystals (CNCs) is of great interest, especially to facilitate their use as polymer reinforcements. Generally, alteration of the surface chemistry is performed using multiple reaction steps. In contrast, this study demonstrates that the hydrolysis of disordered regions of cellulose along with the esterification of accessible hydroxyl groups can be performed simultaneously in a single step to produce surface functionalized CNCs. The reaction is carried out in an acid mixture composed of H2SO4, one type of organic acids (formic, acetic and butyric acids are all demonstrated) and H2O with a mass ratio of 1:7:2 for 3-7 h. The rod-like CNCs could be obtained with a high yield (>70%) and high crystallization index (>75%). Thermogravimetric analysis revealed that all of the obtained CNCs exhibited good thermal stability (Tmax >330 °C) which were better than that of the typical sulfuric acid hydrolysis ones. Moreover, due to the negative charged sulfate groups and ester groups introduced on the surface of CNCs in the mixed acid hydrolysis process, the resultant CNCs showed a typical flow birefringence under polarized light and CNC aqueous suspensions could be stably stored for a long time (over one month). Therefore, the present work demonstrated an efficient and sustainable preparation method for the acyl functionalized CNCs with high yield and good thermal stability.