Cellulose nanofibers (CNFs) were successfully fabricated by fibrillation of wood pulp cellulose into submicron and/or nanoscale nanofibers with a microfluidizer in water solution. CNFs have the great potential as reinforcing materials for polymeric composite materials. The microfibril/nanofibril cellulose (MFC/NFC) have a later dimension of typically 5-10nm and are several micrometers in length. They are not only strong and stiff but also can offer the opportunity for eco-friendly and sustainable bio-composites from renewable resources. Their modulus and strength are 134GPa and 4GPa, respectively, which are superior to glass fibers and compared with aramid fibers. The microfluidizer generates high shear fluid to give rise to the fibrillation of cellulose in an interaction chamber through shear, impact and cavitation. This study investigated the effects of processing conditions of the microfluidizer (nozzle diameter, flow pressure, path number, and nozzle setup configuration) on the morphology and properties of the resultant CNF and nanopapers by wet-laid method. The microscopic study showed that the increase in flow pressure and path number magnificently reduced the CNF diameter, and most CNFs experiencing the complete fibrillation process (10path at 10000psi, 10path at 30000psi, and 10path at 45000 psi) were found less than 100nm in fiber diameter. In addition, the crystallinity index and specific surface area were increased by fibrillation processes, respectively, due to the removal of amorphous region such as lignin and amorphous cellulose etc., and the increased aspect ratio of nanofibers. Their immense surface area and the nanoscopic dimensions can lead to the emerging materials for reinforcements in polymer composites, differentiating from common polymer composites and providing the opportunity for nanoengineered materials that could have not achieved from conventional materials.
Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2011: Advanced Materials, CNTs, Particles, Films and Composites
Published: June 13, 2011
Pages: 66 - 69
Industry sector: Advanced Materials & Manufacturing
Topics: Materials Characterization & Imaging