Thermogravimetric analysis thermodynamics

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. 

Study of the solubility and solid phases encountered in the Zr02-H3P04-H20 system over the temperature range of 20 to 100°C. Techniques used include differential thermal calorimetry, thermogravimetric analysis, infrared spectroscopy and X-ray diffraction analysis. The paper discusses briefly the changes occurring in the solid phases over the temperature shift, but is poor in characterising the solution composition since the concentrations of the constituent ions were below the detectable concentrations. No chemical thermodynamics data are detailed in the paper. 

Thermoanalytical (TA) methods characterize a system in terms of the temperature dependency of its thermodynamic properties and the physiochem-ical reaction kinetics of TPs and TSs. The techniques reviewed here only include differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA). Others also are available, which are useful in the processing plant (1, 2). 

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