Narrow Results

Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline $({\mathrm{\text{XY}}}_3{\mathrm{\text{Z}}}_6{\mathrm{\text{Si}}}_6{\mathrm{\text{O}}}_{18}{({\mathrm{\text{BO}}}_3)}_3{\mathrm{\text{V}}}_3\mathrm{\text{W}}$, where $\mathrm{\text{X}}$ is ${\mathrm{\text{Na}}}^{+}$, ${\mathrm{\text{Ca}}}^{2+}$, ${\mathrm{\text{K}}}^{+}$, or vacancy; $\mathrm{\text{Y}}$ is ${\mathrm{\text{Mg}}}^{2+}$, ${\mathrm{\text{Fe}}}^{2+}$, ${\mathrm{\text{Mn}}}^{2+}$, ${\mathrm{\text{Al}}}^{3+}$, ${\mathrm{\text{Fe}}}^{3+}$, ${\mathrm{\text{Mn}}}^{3+}$, ${\mathrm{\text{Cr}}}^{3+}$, ${\mathrm{\text{Li}}}^{+}$, or ${\mathrm{\text{Ti}}}^{4+}$; $\mathrm{\text{Z}}$ is ${\mathrm{\text{Al}}}^{3+}$, ${\mathrm{\text{Mg}}}^{2+}$, ${\mathrm{\text{Cr}}}^{3+}$, or ${\mathrm{\text{V}}}^{3+}$; $\mathrm{\text{V}}$ is ${\mathrm{\text{O}}}^{2-}$, ${\mathrm{\text{OH}}}^{-}$; and $\mathrm{\text{W}}$ is ${\mathrm{\text{O}}}^{2-}$, ${\mathrm{\text{OH}}}^{-}$, or ${\mathrm{\text{F}}}^{-})$ powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that ${\mathrm{\text{Fe}}}^{3+}$ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher ${\mathrm{\text{Ce}}}^{3+}$ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of ${\mathrm{\text{CeO}}}_2$ and ${\mathrm{\text{Ce}}}_{1-x}{\mathrm{\text{Zr}}}_x{\mathrm{\text{O}}}_2$ crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce–Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of ${\mathrm{\text{Fe}}}^{2+}$ to ${\mathrm{\text{Fe}}}^{3+}$ inside the tourmaline caused by the change in the catalyst redox properties of ${\mathrm{\text{CeO}}}_2$ brought about by doping with ${\mathrm{\text{Zr}}}^{4+}$. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800${}^{\circ }$C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

Crystal structure, surface composition, infrared emission properties and surface electrical properties of tourmaline from Guangxi of China, when subjected to heat treatment in air atmosphere had been studied by some methods, including X-ray fluorescence spectrum (XRF), X-ray diffraction (XRD) meter, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersion spectroscopy (EDS), scanning electron microscope (SEM) and Zeta potential analyzer, etc. Experimental results show that the unit cell of tourmaline would shrink during heat treatment because Fe${}^{2+}$ were oxidized. Moreover, the Fe${}^{3+}$/Fe${}_{\mathrm{\text{total}}}$ inside tourmaline can be raised after treatment. Infrared normal total emissivity of tourmaline reaches 0.87, and infrared radiation energy density is $4.56\times 10^2{\mathrm{\text{W/m}}}^2$. It can maintain excellent infrared emission properties at high temperature. Simultaneously, tourmaline presents negative Zeta potential in the aqueous solution, and its Zeta potential reaches −18.04 mV. Zeta potential of tourmaline was increased to −24.83 mV after heat treatment at 400${}^{\circ }$C, and decrease to −11.78 mV after heat treatment at 600${}^{\circ }$C. These findings may provide reference data for tourmaline’s application in the field of functional materials.

In order to prepare polymerizable organic tourmaline, allyl glycidyl ether (AGE) modified tourmaline powder had been investigated in details by focusing on the experimental parameters of turbidity and subsidence time in liquid paraffin. The experimental results indicated that the organic modified tourmaline have a good dispersity in organic solvent when the weight ratios of AGE to tourmaline was 0.8, weight ratios of the solvent to tourmaline was 4.0, reacted at 140°C for 6h. And the structure of organic modified tourmaline was also characterized by means of IR, XRD and SEM.

The tourmaline undecylenate was prepared by means of the surface organic modification of tourmaline powder with 10-undecenoyl chloride, and the reactive conditions have been optimized with the parameters of turbidity and contact angle of product. Experimental results revealed that the modified tourmaline have a good hydrophobicity when the ratios of 10-undecenoyl chloride to tourmaline was 1.0 and reacted 1.0 h at 50°C in DMF, and structure analysis of modified tourmaline was shown that the hydroxyl of tourmaline surface reacted with 10-undecenoyl chloride to get the polymerizable tourmaline undecylenate, and the crystal configuration of tourmaline has no changed.