A continuous fabrication process for high-strength nanocellulose based long-fiber (NLF) has been researched as a key process to fabricate natural fiber-reinforced polymer composites with high specific modulus and strength. The process was custom-designed by utilizing the wet spinning and stretching methods with dry process. First, nanocellulose was isolated from wood pulp by using a combination of chemical and physical methods. Apparatus for the process was self-produced and the process parameters such as the speed, position, number of wheels were experimentally investigated. Among the various designs, two specific setups were chosen and the speed of the wheels was optimized. The success of the process was determined by the sustainability of the setups for more than 30 min. The results were evaluated by using the tensile test and scanning electron microscope.
Cellulose nanofiber (CNF) is known to have high mechanical strength, high Young’s modulus, optical transparency, low thermal expansion coefficient and low density, which are beneficial for flexible display substrates and optical films. The purposes of this study is to fabricate ultrathin CNF film and to explore its physical properties. CNF suspension is extracted by 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation combined with aqueous counter collision (ACC) treatment from bleached hardwood pulp. The CNF suspension is cast on a thin positive photoresist (PR) layer by a doctor blade casting method followed by removing PR layer and drying on a polytetrafluoroethylene (PTFE) sheet to obtain ultrathin CNF film. Morphology of ultrathin CNF film is characterized by atomic force microscopy and the thickness of the film was characterized by FE-SEM. Transparency and birefringence of the prepared ultrathin CNF film are tested by using an UV-visible spectrometer and a digital camera. The piezoelectric response microscopy (PFM) is utilized to analysis the piezoelectric properties of ultrathin CNF film.