Preparation And Application Of Nanobelt In Papermaking

In recent years, nano-materials have attracted much attention in various fields. Inthis study, sodium titanate nanobelts were synthesized by hydrothermal method, andpeeled by ion-exchange with tetramethyl ammonium hydroxide aqueous solution. Thesynthesized and peeled samples were characterized by transmission electron microscopy（TEM）, X-ray diffraction （XRD）, particle size analysis and zeta potential measurement.The peeled titanate nanobelts were used to flocculate kaolin clay as anionicmicroparticulate component together with cationic polyacrylamide （CPAM）. Theflocculation extent was indicated by the relative turbidity of kaolin clay suspension. Themorphology of kaolin flocs was analyed by using transmission electron microscopy andoptical microscope.Potassium titanate nanowires were also synthesized by hydrothermal method,while potassium titanate nanobelts and lithium titanate nanobelts were synthesized byion-exchange method. Their flocculation effects on kaolin clay suspension werecompared when they constitute microparticle retention aid systems with cationicpolyacrylamide （CPAM） as anionic microparticle component. Magnesium chloridehydroxide was prepared by hydrothermal and ageing methods. The effects ofhydrothermal time and temperature on the morphology and dimendion of themagnesium chloride hydroxide were studied in order to optimize the its synergisticflocculation effects with CPAM on kaolin clay. In the last part, cleaning paper was madeby titanium dioxide nanobelts and cellulose fibers. The silver loading capacity,photocatalytic effect on methyl orange and antibacterial performance of the cleaningpaper with various mass fractions of the titanate nanobelt were compared and studied.Its antibacterial mechanism was analyzed.After being peeled, the average length of the sodium titanate nanobelts wasreduced from1400nm to500nm, and their average width was reduced from180nm to100nm, while their crystal structure and zeta potential were hardly changed. Thesodium titanate nanobelts peeled for6to10days showed the largest synergisticflocculation effect on kaolin clay with CPAM at a very low dosage of0.04%（based onthe mass of kaolin clay）. The kaolin clay flocs became denser and smaller withincreasing the peeling time of the nanobelts.The nanobelts obtained by ion-exchange method were thicker than those obtainedby hydrothermal method. The titanate nanobelts synthesized by hydrothermal method showed better synergistic flocculation effect on kaolin clay with CPAM than thatsynthesized by ion-exchange method. In the synthesis of magnesium chloride hydroxide,when hydrothermal temperature was higher than180℃,the sample was transformed to[Mg₁₀（OH）₁₈Cl₂·5H₂O] phase from Mg₂（OH）₃Cl·3H₂O phase，and the sample preparedat180℃displayed the maximum synergistic flocculation effect at a very low dosage.As the hydrothermal time was longer than6h, and the same crystalline phase transitionas described above also occurred. The magnesium chloride hydroxide with10h ofhydrothermal time showed the maximum flocculation effect on kaolin clay with CPAMat a lower charge level, and induced greater and denser kaolin flocs.The average length of prepared titanium dioxide nanobelts was about5μm. Thesurface of acid etched nanobelts was rough and dotted with nanoparticles of about10-15nm. With increasing the mass fraction of titanium dioxide nanobelts, the degradationeffect of the cleaning paper on methyl orange solution was enhanced. The degradationrate could be attained to100%after the methyl orange sample was irradiated for4h.After being etched by acid and loaded with silver, the photocatalysis effect, especiallythe recyled photocatalysis degradation effect, of the naobelts containing cleaning paperwas significantly improved. Papers loaded with silver all had good antibacterial effect.After the TiO₂nanobelts were added in the cleaning paper, its silver loading andantibacterial effects were further improved. The zone of inhibition was bigger and moreobvious.