Influence Of Liquid Homogeneous Nanotechnology On Supramolecular Structures Of Four Kinds Of Cellulose

Cellulose is an important natural macromolecule material. However, the utilization of cellulose is limited due to its complicated structure. On the one hand, cellulose is a natural composite among cellulose, hemicellulose, and lignin. On the other hand, cellulose is neither meltable nor soluble in water or common solvents due to its partially crystalline structure and close chain packing via numerous inter- and intra-molecular hydrogen bonds. The reaction of cellulose r was reduced resulted from these two structures. Therefore, It will be an important way in cellulose science to isolate free cellulose chains from its natural complicated structure.In order to solve this problem, our team put forward to a new idea of cellulose recombination, which is called liquid homogeneous nanotechnology. First, cellulose is dissolved in a homogeneous solution. Then it is restructured through the super-high pressure stearing during the whole homogeneous solution, And thus the nanocellulose was obtained after regeneration. Compared with other traditional method, this approach is to improve the efficiency of cellulose recombination, avoiding the huge molecluar resistance in solid pase state. In our previous work, nanocellulose from sugarcane bagasse(SCB) with a diameter of about 10 nm was successfully isolated by this method. It suggested that the proposal was carried out by the cellulose recombination effectively, and easy to be industrialization. However, the mechanism and the applicability of this method are still in process.In this study, the effects of supramolecular structure of natural cellulose, such as cotton cellulose, Eucalyptus pulping(wood), sugarcane bagasse(grass) and sisal fibres(bast) were carried out by the liquid homogeneous nanotechnology. The results were as follows:(1) Nanocellulose from four kinds of cellulose were prepared by liquid homogeneous nanotechnology. Parameters of two critical process, were optimized. Nanocellulose were obtained with a diameter of less than 100 nm and the recovery of 100 % under the optimum refining condition. In addition, the dispersity of nanocellulose was narrow.(2) Effects of supramolear structure of four kinds of cellulose are investigated by liquid homogeneous nanotechnology. The results of XRD, XPS, FT-IR and CP/MAS 13CNMR showed that the supramolecular structure of cellulose were changedsignificantly during the whole process. Nanocellulose exhibited a lower thermalstability, crystallinity and weight average molecular weight(Mw). IR results showedthat the band corresponds to OH vibration of cellulose and the intramolecularO(3)H–O(5) shifted toward the higher wavenumber. Besides, It was interesting to notethat chemical shift of C4 and C6 shift to a higher field, suggesting the breakage ofintramolecular O(3)H–O(5) and O(2)H–O(6) between cellulose chains. The resultssuggested that the intramolecular and intermolecular between cellulose chains weredisintegrated by the force in process. Simultaneity long cellulose chains wereseparated, and thus nanocellulose was obtained.(3) Mechanism recombination of cellulose by liquid homogeneous nanotechnology andwere analyzed. We found that the way of cellulose dissolution was different atdifferent temperature. At lower temperature, intramolecular O(3)H–O(5) weredisintegrated, which was facilitated the degradation during dissolution process. Athigher temperature, intramolecular O(2)H–O(6) were collapsed, which could retardthe degradation during dissolution process. Consequently, the cellulose network was destroyed, and the structure was recombinated by the high force, and thus nanocellulose was obtained. In addition, the dynamic ultra-high pressure microfluidization(DHPM) was presented better results with less degradation and lesssize of nanocellulose, which was due to its high shearing force, less operation time and temperature controlling.(4) The applicability of different cellulose on the proposal was carried out. Results showed that effects of supramolecular structure of four kinds of cellulose was different by the liquid homogeneous nanotechnology, due to their different structure.Sisal fibres chains could be interrupted easily by the shearing forces because of its harder texture, which was suited for the method. Other kinds of cellulose could also be well-suited through controling key parameters such as mechnical forces and treatment temperature in the process.In this study, the effects of supramolecular structure of four kinds of natural cellulose were first carried out by the liquid homogeneous nanotechnology at the molecular level. The mechanism of cellulose recombination was analyzed and used for the industrialization. Moreover, it is to provide a theoretical and technical insight for the preparation of biomass material.