Thermogravimetric analysis melting

Glass transition temperature Thermogravimetric analysis Melting point Vinyl acetate Vinyl bromide Vinyl chloride Vinylidene chloride Specific viscosity Density... 

Infrared Spectrum Nuclear Magnetic Resonance Spectrum Mass Spectrum Ultraviolet Spectrum Differential Thermal Analysis Thermogravimetric Analysis Melting Range Solubility... 

Poly(N-phenyl-3,4-dimethylenepyrroline) had a higher melting point than poly(N-phenyl-3,4-dimethylenepyrrole) (171° vs 130°C). However, the oxidized polymer showed a better heat stability in the thermogravimetric analysis. This may be attributed to the aromatic pyrrole ring structures present in the oxidized polymer, because the oxidized polymer was thermodynamically more stable than the original polymer. Poly(N-phenyl-3,4-dimethylenepyrroline) behaved as a polyelectrolyte in formic acid and had an intrinsic viscosity of 0.157 (dL/g) whereas, poly(N-pheny1-3,4-dimethylenepyrrole) behaved as a polyelectrolyte in DMF and had an intrinsic viscosity of 0.099 (dL/g). No common solvent for these two polymers could be found, therefore, a comparison of the viscosities before and after the oxidation was not possible. 

In a study on the thermal and UV ageing of two commercial polyfoxymethy-lene) (POM) samples, one of which was a copolymer (see related study discussed later under Section 4.3, thermogravimetric analysis (TGA)), used in car interior applications, involving both DSC and TGA, isothermal OIT measurements were made at several different temperatures [8]. One conclusion from this study was that "extrapolation of the OIT data from high temperatures (molten state) to ambient temperatures in the solid state does not reflect effective antioxidant performance at room temperature", and thus measurements close to the melting point are not appropriate for reliable lifetime estimations. 

Three flame retardants were compared in this study, namely, a brominated polycarbonate oligomer (58% bromine), a brominated polystyrene (68% bromine), and a brominated triaryl phosphate ester (60% bromine plus 4% phosphorus). These are described in Table I. Figures 1 and 2 compare the thermal stability of the brominated phosphate with commercial bromine-containing flame retardants by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). The brominated phosphate melts at 110°C and shows a 1% weight loss at 300°C. Brominated polycarbonate and brominated polystyrene are polymeric and are not as volatile at elevated temperatures as the monomeric flame retardants. 

All the polyimides are thermostable. They do not melt before decomposition at high temperature. In thermogravimetric analysis, the decomposition starts at more than 400°C. 

The [Cr(H20)(0H) 0P(C H8)20 2]a polymer is a green solid which is readily soluble in chloroform, benzene, and tetrahydro-furan but is insoluble in water and diethyl ether. It does not melt before decomposing thermogravimetric analysis indicates decomposition starting at 365°C. A freshly prepared solution in chloroform has an intrinsic viscosity ranging from 0.03 to 0.04 dl./g. The intrinsic viscosity increases slowly when solutions in organic solvents (for example, 1 g./lOO ml. in chloroform) are allowed to stand at temperatures of approximately 55°C., and values of 0.6-0.8 dl./g. are common after a number of days. A sample with an intrinsic viscosity of 0.04 dl./g. 

Since polysulfone is often melt processed at high temperatures (up to 370°C), another requirement of a successful impact modifier is that it display adequate thermal stability at these temperatures. As expected from the known good thermal stability of polysulfone and silicones (10, 11), the PSF/PSX block copolymer displays excellent thermal stability. This is illustrated by the thermogravimetric analysis curves shown in Figure 6. 

Analytical techniques commonly used to check for solid-state characteristics include melting point (including hot-stage microscopy), solid-state infrared spectroscopy, x-ray powder diffraction, thermal analysis (e.g., differential scanning calorimetry, thermogravimetric analysis, and differential thermal analysis), Raman spectroscopy, scanning electron microscopy, and solid-state nuclear magnetic resonance (NMR). 

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