Investigation of native cellulose under high pressure using microfocused synchrotron radiation

Abstract

The mechanical properties of native cellulose are critical for understanding the properties of natural biomaterials. To investigate the elastic moduli of the cellulose crystalline fraction an isotropic mechanical load using hydrostatic pressure ranging from 0.01 to 0.5 GPa was applied to flax fibers, pine wood and tension wood samples. The response of the crystalline part was monitored by using microfocused synchrotron radiation. The compressibility of the crystalline fraction of native cellulose was anisotropic and dependent on the crystal size and possibly on the composition of the sample. The compressibilities along the [001] direction, where covalent bonds hold the cellulose chains together, varied between 2.1 and 2.9 TPa−1 for the different samples and confirm similar values found for cotton fibres. However, the compressibilities along the [100]-direction range from 56.2 TPa−1 to 63.5 TPa−1, slightly exceeding the previously determined value of 50 TPa−1, which can possibly be attributed to differences between individual samples.