Cellulose Nanofibers-Reinforced Epoxy Resin Composite

Cellulose is one of the most abundant resources in the world, and its biodegradability, highavailability, diversity, abundance, renewability and low cost has many applications. Thecellulose fibers in nanoscale can be designed or combined with different structures, and thenthese cellulose molecules and supramolecular aggregation can created some newnano-chemicals and new nano-materials what are the forefronts of cellulose science now. So thetransparent material, barrier material, tissue engineering material and ultrafiltration membraneis the hot discussion in the world.In this paper, the wood powder was prepared to be the cellulose nanofibers (CNFs) by thechemical and mechanical treatment, and the CNFs solution was vacuum filtered to be the film.Then the compatibility and immersion method were chosed to obtain the epoxy nanocomposite.The micro morphology and chemical structure of the CNFs were observed through the scanningelectron microscopy (SEM), infrared spectroscopy (FTIR) and the optical microscope. Thetensile Machine, the UV-visible spectrometer and the thermomechanical analyzer were used toanalyse the CNFs film, the epoxy resin film and their nanocomposites'performance. There alsowas a discussion about the property of the CNFs-reinforced epoxy resin composite which madefrom the paper and the cotton, and then compared with that of wood fiber.The results of this paper is as follows:(1) The wood powder was separated to the CNFs. In the process of the chemical treatment,the lignin was removed by the acid, and the hemi-cellulose was removed by the alkali throughthe observed of the FT-IR, and the HCl facilitate the separation of the CNFs through the opticalmicroscope. The grinding apparatus, the ultrasonic generator and the high pressurehomogenization was the mechanical method to obtain the CNFs, and the image of the FE-SEMwas revealed that the CNFs' diameter was uniform occurring in20-80nm after the grind for30times and the homogenization for30min.(2) The CNFs solution was vacuum filtered to be a film, and the layer structure and thecross linked of the fibers was obversed by the SEM. The structure of network in the CNFs filmstrengthened the epoxy nanocomposite's tensile strength reached159.2MPa, and modulus ofelasticity and the elongation at break were7.3GPa and6.1%respectively. And because of theCNFs' high aspect ratio and the diameter's uniform distribution, the CNFs film has great lighttransmittance and thermostability that the values were86%and14ppm/K respectively.(3) The epoxy nanocomposite by the compatibility method has a little increase in thetensile properties, light transmittance and the thermostability becaues of the small content of theCNFs in nanocomposite. The content of the CNFs could reach90%by the immersion methodso that tensile strength and Young's modulus were112.6MPa and4.9GPa; the light transmittance could reach87.7%that the light transmittance was below5%compared with theneat epoxy resin film; and the coefficient of thermal expansion (CTE) was17ppm/K.(4) The CNFs was obtain from the printing paper and the cotton, and then made the epoxynanocomposite. The results found that the different raw material had no influence on the CNFs,and the value of the tensile properties, light transmittance and the thermostability was alsosimilar compared with that made from the wood powder. The variation trend was same betweenthe CNFs film, the epoxy resin film and the epoxy nanocomposite.