Mechanical properties of cellulose Iβ crystal were studied using molecular dynamics. Firstly, mechanical properties of the cellulose Iβ crystal model offered by Nishiyama were calculated. By analyzing the mechanical parameters of cellulose Iβ crystal, it was found that the cellulose Iβ crystal was the anisotropic elastic material whose elasticity was much bigger in the direction of chains of cellulose molecules than other two directions and had good ductility. The Young s modulus also agreed with the data which was calculated by Tanaka. Subsequently, the mechanical properties of cellulose Iβ crystals were calculated under the transformer operating temperatures. The changes of mechanics parameters were not obvious under the transformer temperatures. The same law was also found when calculating the density of hydrogen bond in the crystals under different temperatures, but the standard deviation of the density of hydrogen bond became bigger when the temperature increased, reflecting the influence of temperature to the stability of cellulose crystals. Through analysis of density distribution in the direction of crystal layer, with the temperature increasing, the standardized crystal structure became weakened. Finally the movement of chains had been studied and found that the higher the temperature was, the more intensely the movement of chains were, which agreed with the result manifested by the density of hydrogen bond.

Key words: cellulose Iβ crystal, temperature, mechanical properties, hydrogen bond density, density distribution, movement of chains