원문정보
초록
영어
Acid hydrolysis is the most common method to prepare cellulose nanocrystals (CNCs). citric acid (CA) is a weak poly-carboxylic acid which is beneficial for avoiding cellulose undergoing heavy degradation during acid hydrolysis. However, the weak acidity of CA can mostly lead to a difficulty in hydrolyzing the amorphous part of the cellulose and correspondingly results in a low yield of CNCs. In this work, CNCs were produced from bleached eucalyptus kraft pulp with a high yield over 76% via FeCl3-catalyzed CA hydrolysis process. It was found that the resultant CNCs products with a diameter of 20-30 nm and length of 200-400 nm, and a maximum crystallinity index of about 78% could be achieved when the dose of FeCl3 was 0.03 mM, CA concentration was 80%, and reaction temperature was 80 °C. Meanwhile, carboxylic groups could be introduced onto the surface of CNCs via esterification during FeCl3-catalyzed CA hydrolysis process to form carboxylic CNCs . Results showed that the contents of carboxylic acid groups could reach up to 0.69 mmol g-1, which facilitate their functionalization and dispersion in aqueous processing. The carboxylic CNCs presented in this work offer commercial success and lower toxic risks, which means they have the potential to find applications as environmentally friendly, sustainable, and new bio-based nanomaterials in high-tech fields, such as biomaterials.