X-ray study of thermal expansion and transition of crystalline cellulose

Abstract

For the cellulose crystals I and II, the spacings and intensities of some typical X-ray reflections were measured over a range of temperature from room temperature to 200°C. The spacing vs. temperature curve for each reflection exhibited a distinct break at about 150°C for Cell I and at about 100°C for Cell II. The thermal expansion coefficients estimated from this curve for the (101) reflection of Cell I were 5.1×10−5 K−1 below 150°C and 1.6×10−4 K−1 above 150°C. The intensity vs. temperature curve for each reflection also exhibited a break at the same temperature as that for the break of the corresponding spacing vs. temperature curve. The reason for the appearance of these breaks is not yet clear. © 1982 The Society of Polymer Science, Japan.