Preparation of spherical cobalt hydroxystannate and its flame retardant and smoke suppressant effect in poly(vinyl chloride)

2020 ◽  
Vol 38 (5) ◽  
pp. 462-482
Author(s):  
Fuya Liu ◽  
Zewei Wen ◽  
Ning Zhang ◽  
He Zhao ◽  
Weidong Hu ◽  
...  

Spherical cobalt hydroxystannate was prepared and characterized by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analyzer–Fourier-transform infrared spectroscopy. Results showed that cobalt hydroxystannate spheres have an average particle size of 440 nm and disperse uniformly. The flame-retardant flexible poly(vinyl chloride) treated with cobalt hydroxystannate was studied by the limiting oxygen index, universal tensile testing machine, thermogravimetric analyzer–Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and laser Raman spectra methods. Compared with the pure poly(vinyl chloride), the limiting oxygen index value of the poly(vinyl chloride) sample (PVC/10) treated with 10 phr of cobalt hydroxystannate is increased by 4% points, and its total heat release and total smoke production decreased by 18% and 50%, respectively. The result could be attributed to the water produced by the dehydration of cobalt hydroxystannate, and the interaction of cobalt hydroxystannate and the poly(vinyl chloride) matrix, which produces dense and highly graphitized char residue containing hexagonal phase graphite, CoCl2, Co2O3, and Co3O4.

2019 ◽  
Vol 9 ◽  
pp. 184798041985255 ◽  
Author(s):  
J Adnan ◽  
M Arfan ◽  
T Shahid ◽  
MZ Khan ◽  
R Masab ◽  
...  

Polycrystalline cadmium hydroxide nanomaterials have successfully been synthesized by composite-hydroxide-mediated approach with growth time variation. The influence of growth time on structural, morphological, elemental, and optical properties was explored using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and ultraviolet–visible spectroscopy. X-ray diffraction results revealed the hexagonal and monoclinic phases of cadmium hydroxide along with rhombohedral impurity phase of cadmium carbonate. Fourier transform infrared spectroscopy further endorsed the X-ray diffraction results and confirmed the Cd–O bonding vibrations. Time-dependent uniform distribution of spherical morphology was observed in the scanning electron micrographs of the product. The presence of cadmium and oxygen in the energy dispersive X-ray spectroscopy results fingerprinted the purity and formation of the desired nanomaterials. Crystallite size was decreased with the increase of growth time as estimated by the Debye–Scherrer method. Furthermore, the optical bandgap was measured by Tauc’s relation using ultraviolet–visible absorption spectra and found to be in the range of 3.2–3.5 eV.


1996 ◽  
Vol 11 (3) ◽  
pp. 703-715 ◽  
Author(s):  
H. C. Zeng

The PbO/MoO3 system with 47%: 53%, 53%: 47%, and 50%: 50% molar ratios at various processing temperatures has been studied with x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential thermal analysis (DTA) methods. It is found that in addition to the crystallization of primary PbMoO4 phase, subphases such as Pb2MoO5 and PbMo2O7 are also formed. The remaining PbO and MoO3 are detected at certain stages of the thermal process due to localized powder inhomogeneity. Physical processes, such as sublimation, eutectic melting, solid to liquid, and liquid to vapor transformations are also investigated. In particular, evaporations of excessive PbO or MoO3 in the nonstoichiometric PbO/MoO3 can be correlated to thermal processing parameters. The current study has led to the following three processing guidelines to obtain stoichiometric PbMoO4: (i) for high temperature application, such as the Czochralski melt growth, it is suggested an excessive MoO3 (a few mol %) must be included and a slow heating rate should be employed; (ii) for low temperature synthesis, the stoichiometric PbO–MoO3 can be used, but with a fast heating rate; and (iii) PbO-rich PbO/MoO3 system is not recommended in PbMoO4 synthesis.


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