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Abstract

The objective of this study was to examine the crystallinity of the cellulose of seven fully bleached pulp samples by using solid-state cross-polarization/magic angle spinning (CP/MAS) 13C Nuclear Magnetic Resonance (NMR) spectra in combination with line-fitting analysis and how it affected the hygroexpansional properties of handsheets. Differential scanning calorimetry was used to measure the pore size distribution of the samples and to characterize the water inside the fiber wall. Combined with the CP/MAS 13C NMR analysis, mechanisms behind the moisture absorbing capacities of various hardwoods were studied. Based on the results, the hygroexpansional behavior of the handsheets and the Crystallinity Index of the cellulose in the samples were not inter-correlated. The fiber wall thickness measured with a FiberLab® fiber analyzer had a moderate correlation with the amount of crystalline cellulose and xylan of the samples, implying that the crystalline and the amorphous regions were evenly distributed in the fiber wall.