Research On Cellulose Nanofibers/Acrylic Resins Composites

Recently, cellulose nanofibers (CNFs) have attracted wide attention by researchers due totheir high aspect ratio, high purity, high crystallinity, high Young modulus, high strength,biodegradable and good biocompatibility. In this thesis, the main contents are:(1) Study inpreparation of biomass CNFs;(2) Comparison with different effects that raw materials have onproperties of biomass CNFs film;(3) Comparison with different effects that mechanicalseparations have on properties of biomass CNFs;(4) Analysis on the micromorphology ofbiomass CNFs and mechanical properties, thermostability of their films;(5)Study in mechanicalproperties, thermostability and regular transmittance of biomass CNFs/ABPE10composites;(6)Comparison with different effects that fiber contents have on properties of CNFs/ABPE10composites. The main conclusions are as follows:1. The use of chemical pretreatment removed lignin and most of the hemicellulose in woodraw material, and using HCl could help to open fibers. Then, with grinding treatment, the highaspect ratio, mesh tangle morphology of wood CNFs were prepared.2. After chemical pretreatment combining with grinding, we could extract CNFs fromwood, corrugated paper pulp and cotton. All of the nanofibers had high aspect ratio and meshtangle morphology. CNFs of the wood and corrugated paper which contain "low" cellulosewere fibrillated well while some of the aggregates existed in cotton CNFs. When CNFs fromdifferent raw materials were compared, tensile strength and elastic modulus of cotton CNFsfilm were obtained,87.38MPa and3464.23MPa, respectively, which were higher than CNFs ofwood and corrugated paper. However, the CTE of cotton CNFs film (14ppm·K-1) was lowerthan the other two kinds of CNFs. Besides, the fracture surface of cotton CNFs film was worsethan film of wood CNFs and corrugated paper CNFs.3. All of the CNFs extracted by different mechanical treatment had high aspect ratio andmesh tangle morphology. High intensity ultrasonication/grinding/high pressure homogeneitytreatment was the best method in them. Tensile strength and elastic modulus of it were thegreatest,159.78MPa and6467.23MPa, respectively. CTE of it was the lowest, which was only12ppm· K-1. Moreover, the fracture surface of CNFs treated by high intensityultrasonication/grinding/high pressure homogeneity was excellent.4. Wood CNFs film was impregnated in transparent acrylic resins ABPE10under pressureto prepare wood CNFs/ABPE10composites, which was more transparent than the nonpresssureone. When adding CNFs to acrylic resins, the tensile strength and elastic modulus ofnanocomposites were improved to56.52MPa and2613.84MPa, respectively, while CTE wasreduced to23ppm·K-1. The regular transmittance of composites was also decreased.5. Different CNFs contents were added to acrylic resins to prepare different nanocomposites which transparency could hardly be distinguished. However, with the CNFscontent increased, the tensile strength and elastic modulus of nanocomposites were improved,while the CTE and regular transmittance decreased.6. Based on the paper, the CNFs reinforced nanocomposites which were strong andthermostable have the potential to be used as base substrate for flexible organic light-emittingdiode displays (FOLEDs).