THE INFLUENCE OF METHOD OF CELLULOSE ISOLATION FROM WOOD ON THE DEGREE AND INDEX OF CRYSTALLINITY

Abstract

An attempt was made to find the correlation between the crystallinity index, as determined by FTIR, and the crystallinity degree, as determined with the WAXS technique. Analyzed cellulose was isolated from pine and poplar woods with the Kurschner-Hoffer method, while the number of cycles varied from 1 to 9. The degree of cellulose crystallinity changed depending on the number of cycles. The degree of cellulose contamination by lignin influenced the quality of results obtained regarding the crystallinity index. Lignin content was the highest after 1 to 3 cycles, but then significantly decreased (especially in pine wood). Vibrations of the C-H group originated from lignin and cellulose overlap, causing the overestimation of the crystallinity index after these cycles. For the rest of the cycles, the correlation between the crystallinity index and crystallinity degree (measured with WAXS) was different for pine and poplar woods and appeared to be caused by effects related to the presence of lignin.