Direct mechanical production of wood nanofibers from raw wood microparticles with no chemical treatment

Wood nanofibers (WNFs) were directly isolated from raw wood micro-particles (WMP) of Paulownia using disk grinding with no chemical treatments. TEM analysis showed that the average diameter of the WNF is 55 +/- 22 nm, which is 4800 fold less than that of WMP (265 +/- 45 mu m). The production mechanism of WNF was discussed. XRD results confirmed that the crystallinity and crystallite size of WNF were lower than those of WMP. Chemical composition measurements and FTIR results showed that the chemical compositions of WNF and those of WMP were almost the same. A TGA test also demonstrated that the thermal stability of WNF and WMP was the same (250-260 degrees C), and the char content of WNF was slightly lower than that of WMP. The direct production of WNF from WMPs with no chemical treatments is an environmentally valuable approach and WNF can be regarded as a promising sustainable nanomaterials with abundant potential applications.