Papers by Keyword: Thermogravimetry (TG)

Abstract: As an important type of additive, the redispersible powder is widely applied in cement-based and gyp-based materials, so as to improve the cementing strength, impermeability, workability, hydrophobicity and so on. However, the chemical composition of the redispersible powders determines its applicability, as well as the degree of improvement to the matrix materials. In this paper, the chemical composition of an unknown redispersible powder was analyzed by several instruments. Firstly, Fourier transform infrared spectroscopy (FTIR) analysis indicated that the polymer was polymerized with monomers of vinyl esters. Secondly, pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) analysis showed the pyrolysis products were mainly acetic acid, methyl acetate and methyl versatates. Considering the pyrolysis mechanism of synthetic polymers and the results from FTIR spectra, the polymer in the redispersible powder was deduced to be the copolymer of vinyl acetate and vinyl ester of versatic acid (VeoVa), which was a monomer with a unique highly branched carbon-rich structure. Thermogravimetry (TG) analysis revealed that the powder contained 74.0% of polymer, 14.5% of calcium carbonate and 11.4% of other inorganic materials.

Abstract: The combustion performance of adding different metal hydroxide flame retardants in asphalt was investigated by the limit oxygen index test, and the flame retardant process of hydroxide flame retardant was studied by thermogravimetric analysis. The results showed that calcium hydroxide, magnesium hydroxide, aluminum hydroxide all play positive roles on flame retardancy of asphalt. Aluminum hydroxide has the best effect on flame retardation; calcium hydroxide and magnesium hydroxide show similar flame retardation. The temperature range of the decomposition of different metal hydroxide was different. Aluminum hydroxide has the lowest decomposition temperature, while calcium hydroxide has the highest decomposition temperature. Barrier layer composed of metal oxides is formed after the decomposition of flame retardant , which can prevent the further burning of asphalt.