The Preparation Of Micro-nano-cellulose And Its Application In Paper Coating

Cellulose is the most abundant natural polymer material in nature. It is now gettingextensive attention due to its reproducibility and non-pollution to environment. However,large amounts of hydrogen bonds exist both intramolecularly and intermolecularly, whichresults in complex aggregated state structure and high crystallinity of cellulose. As a result,the application of cellulose is restricted. If the crystallinity of cellulose is reduced, theapplication of cellulose will be extended.The traditional cellulose material, such as pulp and wood flour, can be produced tomicro-nano-cellulose crystal by acid hydrolysis, oxidative and mechanical degradation. Themicro-nano-cellulose crystal can dissolve in common aqueous alkali. The celluloseregenerated from the alkali and then homogenized with a high pressure homogenizer, can beprepared to micro-nano-cellulose with quiet low crystallinity. XRD and FTIR resultsindicate that cellulose change to Cellulose-Ⅱ from Cellulose-Ⅰduring the regenerationprocedure and the crystallinity reduced significantly. More amorphous component appeared.TG results indicate that the heat stability of micro-nano-cellulose is not as good as the rawcellulose. The size of micro-nano-cellulose is influenced by the pressure and times ofhomogenizing procedure.Micro-nano-cellulose can be used for paper coating as it has no harm to environment.The traditional coated paper which has large amount of resin could be easily permeatedthrough by water. Micro-nano-cellulose and paper fiber can form strong hydrogen bondsand the coating is nontoxic, so the coated paper can be used as packaging material for food.If the silica and Ammonium Zirconium Carbonate (AZC) are added in the coating material,high-grade printing paper with good ink adsorption can be produced.Paper coated by micro-nano-cellulose has a smoother surface because cellulose fill thegap of paper surface. The tensile strength and fracture strength of coated paper is better thanthe uncoated paper. The roughness of coated paper increased and the air permeabilitydecreased as the amount of silica increased. Coated paper with AZC shows high tensilestrength and fracture strength than that without AZC. The results show that AZC, as across-linking agent, linked paper and cellulose. The rotating viscosity of cellulose with AZC has a high viscosity than cellulose without AZC. The viscosity decreased at60℃becauseAZC decomposed above60℃.