Graphitization of highly crystalline cellulose

Native cellulose samples of high crystallinity were pyrolyzed in nitrogen and the structure of the resulting carbon was studied by X-ray diffraction and transmission electron microscopy. All samples became amorphous carbon after treatment at 500°C and were then graphitized at 2000°C. All the graphite samples showed strong 002 reflections in X-ray diffraction, but only the ex-Halocynthia sample gave 100 and 101 reflections showing the presence of three-dimensional order. The order of crystallinity was Halocynthia (tunicin)∼Cladophora (alga)>Acetobacter>ramie (linen). Electron microscopy showed that the graphite samples, except for the ex-ramie, contained long microfibrillar units, indicating that certain portions of the cellulose microfibrils were graphitized while retaining their morphology.