Synthesis And Properties Research Of The Emulsion Of Nanocrystalline Cellulose Graftted With Fluornated Acrylate

In this paper, with Nanocrystalline cellulose (NCC) which was prepared by the method of acid hydrolysis as graft framewok, hexafluorobutyl methacrylate as monomer, the emulsion of NCC grafted with fluorinated acrylate was prepared through emulsion grafting polymerization. The properties of the emulsion were researched. The specific results are as follows:Through single factor analysis, several effect factors of emulsion grafting polymerization, i.e., the dosage of emulsifying agent, the dosage of initiator, the quality ratio of monomer to NCC and the reaction time were researched. When the condition was that the ratio of emulsifier species was SDS:OP-10:S200=1:2:0.5, the dosage of emulsifying agent was4.5%, the dosage of initiator k2S2O8was4%, the reaction temperature was60℃, the reaction time was4h, and the quality ratio monomer and NCC was5:1, the percentage of grafting copolymerization, the grafting efficiency, and the conversion rate of monomer could reach125.24%、30.89%、90.1%respectively. Using headspace gas chromatography method to detect the residual monomer concentration in samples, the effect of the concentration of NCC on the reaction rate was researched, and it was found that the reaction rate was raised from0.0040mol-1·s-1to0.0059mol-1·s-1when the concentration of NCC changed from Og/L to4.88g/L.Fourier-infrared spectroscopy(FTIR), X-ray diffractometer(XRG), thermal gravimetric analysis(TGA), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and other means of testing were adopted to characterize the changes of chemical structure and microscopic appearance of NCC before and after reaction. The FTIR figures showed that the grafted NCC had structures of the stretching vibration peaks about C=O,-CF,-CF2and-CF3. The XRD results showed that the crystallinity of NCC increased compared to the original fiber and the crystallinity of NCC grafted with hexafluorobutyl methacrylate reduced. The TGA showed that NCC had lower thermal stability towards bagasse pulp cellulose; the thermal stability of the grafted NCC became slightly higher than the original NCC and the grafted NCC showed another thermal decomposition stage of grafting copolymer. The FESEM and FETEM analyzes showed the microcosmic morphology changes of NCC after grafting. All above analyzes, it was proved that graft copolymerization happened beteween NCC and fluorinated monomer.The Solid content, particle size distribution, film-forming property and stability of NCC graft copolymer emulsion were determined. The zeta potential tests and nano particle size analyzes showed that the dispersion of NCC and stability of the NCC graft copolymer emulsion were improved after modifying. The emulsion dried film was found tobe dense through FESEM analyze, which proved to have good ability of film-forming. The coating application experimentation showed that the waterproofing ability and tensile index of coating paper would be enhanced by directly using fluorinated monomer grafting emulsion. And if the emulsion combined with cationic starch was used for coating, the tensile index of coating paper would be increased, but the waterproofing ability would not be promoted much.