Studies of crystallinity of Scots pine and Norway spruce cellulose

The variation in the mass fraction of crystalline cellulose (crystallinity of wood), the intrinsic crystallinity of cellulose, and the thickness of cellulose crystallites in early wood of Norway spruce [Picea abies (L.) Karst.], and Scots pine (Pinus sylvestris L.) grown in Finland were studied using wide angle X-ray scattering and nuclear magnetic resonance spectroscopy. The mass fraction of crystalline cellulose in wood increased slightly with the distance from the pith and was about 30+/-4% in mature wood of both species. The crystallinity of cellulose and the thickness of cellulose crystallites were almost constant for both species. The crystallinity of cellulose was 52+/-3% for both species and the average thickness of the cellulose crystallites was 32+/-1 Angstrom and 31+/-1 Angstrom for Norway spruce and Scots pine, respectively. The mass fraction of cellulose in wood, calculated from the crystallinity values, increased with the distance from the pith for both species.