Abstract: Nanocellulose crystal was prepared by sulfuric acid hydrolysis. The effects of sulfuric acid mass fraction, temperature and time on the yield of nanocellulose crystal were optimized with response surface methodology. The mathematical model was established using the Design-Expert software. The effect of various factors and their interactions were analyzed as well. The results showed that quadratic model was the best model to describe the relationship between the yield of nanocellulose crystal and the factors. The determination coefficient and adjusted determination coefficient were 99.31 % and 98.43 %, respectively. The interactions between sulfuric acid concentration and temperature, sulfuric acid concentration and time, temperature and time were significant. When sulfuric acid concentration, temperature and time corresponded to 54 %, 52 ℃ and 125 min, the yield of nanocellulose crystal would reach 69.31 %. It is the highest value in this investigation.

Key words: nanocellulose crystal, acid hydrolysis, response surface methodology