The Preparation And Application Research Of Cellulose-Based Composite Materials

In this paper, we prepared a series of iridescent films with different color by changing conditions via Vacuum-Assisted Self-Assemble (VASA) technique. We explored the internal structures of the iridescent films by Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Froutier transform infrared spectroscopy (FTIR), Wide-angle X-ray diffraction (WAXD) and Circular Dichroism (CD) analysis, and the properties of the iridescent films were also investigated.After the exploration of the sulfuric acid hydrolysis of cellulose, we have obtained ribbon-like micro-cellulose nanocrystals and cotton cellulose nanocrystals (CNCs), and found that the average particle size of cotton cellulose nanocrystals is much larger than the micro-cellulose nanocrystals. Then the cellulose nanocrystals solution was vacuum-filtered to be films, and their thermal property and internal structure were studied. The crystal form of cellulose wasn’t changed after hydrolysis, but its thermal performance was decreased largely because of the grafted sulfoacid group on the cellulos nanocrystal surface.We fabricated the CNCs films with or without iridescence after short sonication and long sonicate of CNCs suspension via VASA. Thus prepared iridescent films have large area, smooth film surface, excellent transparency and no crack. Besides, the iridescence of the film will vary with the angle of incident light. By vertical and oblique section SEM cross images, it is chiral nematic liquid helical structure organized by cellulose nanorods. The chirality was testified to be left-handed, and this is also the origin of the iridescence of the CNCs films. We have also prepared CNCs films with different color and thickness by varying ultrasonic period, CNCs suspension volume and vacuum degree.In order to discuss the effect of the compatibility between the addition GO and CNCs on the CNCs hybrid films’iridescence and properties, we designed two different paths to acquire GO/CNCs hybrid films. Given the experiment data, the film obtained from the stable GO/CNC solution shows no iridescence, while the film from the metastable GO/CNC solution shows iridescence. Undergoing chemical reduction of the GO/CNC hybrid films, the inner ordered structure of the iridescent GO/CNC film was not damaged, and there still showed iridescence. Furthermore, these two kinds of hybrid films had good conductivity.Based on the above work, we integrated the conductive two-dimensional TRG lamella with one-dimensional cellulose nanorod and obtained a composite film with bright metallic iridescence. The ultrasonic time and TRG content was varied to prepare TRG/CNC composite with different colors. Thus films had not only conductivity, but also intense response to water. We studied the influence of internal structure on the water-response property, and we believed the addition of TRG changed the helix of the liquid structure, and the TRG absorbed water as a kind of coloring agent. Therefore, the iridescent TRG/CNC films had intense response to water.