Differential thermal gravimetry

The thermal characterisation of elastomers has recently been reviewed by Sircar [28] from which it appears that DSC followed by TG/DTG are the most popular thermal analysis techniques for elastomer applications. The TG/differential thermal gravimetry (DTG) method remains the method of choice for compositional analysis of uncured and cured elastomer compounds. Sircar s comprehensive review [28] was based on single thermal methods (TG, DSC, differential thermal analysis (DTA), thermomechanical analysis (TMA), DMA) and excluded combined (TG-DSC, TG-DTA) and simultaneous (TG-fourier transform infrared (TG-FTIR), TG-mass spectroscopy (TG-MS)) techniques. In this chapter the emphasis is on those multiple and hyphenated thermogravimetric analysis techniques which have had an impact on the characterisation of elastomers. The review is based mainly on Chemical Abstracts records corresponding to the keywords elastomers, thermogravimetry, differential scanning calorimetry, differential thermal analysis, infrared and mass spectrometry over the period 1979-1999. Table 1.1 contains the references to the various combined techniques. 

FIGURE 15.6 Differential thermal gravimetry of pyrolysis for polyacrylic acid (PAA ... 

The thermogravimetry is an experimental technique based on registration of loss in weight carried out for isothermal or tempera-ture/time programmed conditions and can be displayed in cumulative Thermal Gravimetric Analysis (TGA) or derivative Differential Thermal Gravimetry (DTG) forms. 

Ph2P(S)CH2PPh2 Ph2P(Se)CH2PPh2 diphosphopyridine nucleotide dihydronicotinamide adenine dinucleotide bis( 1,4-diphenylphosphino)butane bis( 1,2-diphenylphosphino)ethane bis( 1,1 -diphenylphosphino)methane bis( 1,3 -diphenylphosphino)propane diphenyl sulphoxide differential thermal gravimetry... 

Tribasic lead sulfate (3Pb0-PbS04 -H20) eontains water in its molecule. On heating the paste samples during the differential thermal gravimetrie (DTG) measurements, this water evaporates and the samples lose weight. 

The possibility was studied of using ammonium salts as plasticisers for wood-based composites, and the breakdown of the ammonium salts during heating was studied by differential thermal gravimetry. 15 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

The differential thermal gravimetry (DTG) curves of RURAL SB and VERSAL 250 are given in Fig. 6. RURAL SB has been described earlier by Decleer [17]. The first endothermic peak is due to the desorption of water and the second due to the conversion of pseudoboehmite to 7—alumina. This conversion takes place over a broad temperature range, dependent on the crystallinity of the pseudoboehmite. For nearly amorphous pseudoboehmite the conversion takes place at a temperature as low as 300 °C [18], while on the other hand the conversion of well crystallized boehmite takes place in a narrow temperature range between 450 and 580 °C [18]. Hence, each different type of pseudoboehmite requires a new evaluation of its thermal behaviour. 

Experimental studies on the thermal decomposition and combushon processes of AP have been carried out and their detailed mechanisms have been reported.P-iil Fig. 5.1 shows the thermal decomposition of AP as measured by differential thermal analysis (DTA) and thermal gravimetry (TG) at a heating rate of 0.33 K s"f An endothermic peak is seen at 520 K, corresponding to an orthorhombic to cubic lattice crystal structure phase transition, the heat of reaction for which amounts to... 

Fig. 5.1 Thermal decomposition process of AP measured by thermal gravimetry (TG) and by differential thermal analysis (DTA).

St CA 54, 15934(1960) (Differential thermal analysis and thermo gravimetry of some salts of Gu and related compounds) (Compares thermal stability, decon temp and 5-kg impact sensitivity of Picrates and Styph-natesof Hydrazine, aminoguanidine, N-tnethyl-guantdine, guanylurea, N-ethylguanidine and Gu)... 

Thermal gravimetry (TG) and differential scanning calorimetry (DSC) are useful techniques in the analysis of inclusion compounds. If we consider the desolvation of a host-guest compound with a volatile guest ... 

Figure 9. Thermal analysis of levoglucosenone samples (a) neat, (b) +5% zinc chloride, (c) +5% diammonium phosphate, and (d) +5% diphenyl phosphate (D.t.a., differential thermal analysis T.g., thermo gravimetry D.t.g., derivative of thermogravimetry)...

To estimate thermal stability of obtained polyethylene-terephthalate/layered silieate nanoeomposites the following well-known methods were used thermal gravimetrie analysis (TGA), differential scanning calorimetry (DSC) and melt thermal stability coefficient determination. Results of thermal stability researeh for polyethyleneterephthalate/layered silieate are shown in Table 2. 

Boyle et al. [318] have used real-time diffraction at a synchrotron source for following the effect of heat treatment of various doped PANIs. The x-ray data are supplemented by mass spectroscopy, thennal gravimetry and differential thermal analysis data. The authors consider PANI-HCl, PANI-HCIO4 and PANl-H2SO4, as well as a sample free of dopant but containing water. Diffraction patterns are decomposed into Gaussian peaks in order to describe the evolution... 

About lOmg of intercalated compound, montmorilonite and a mixture of DPD and alumina powder were examined by differential thermal analy-sis(DTA) and thermo-gravimetry (TG). The measurements were made in 200cm /min. of nitrogen flow, reference was alumina and heating rate was 5K/min. 

The specific surface area was obtained from the nitrogen adsorption and desorption isotherms at 77 K, using a micro-BET apparatus (an AccuSorb 2100 of Micromeritics). The X-ray diffraction (XRD) patterns were recorded on a MAC Science MXP-18 instrument using Cu-Ka radiation with a Ni filter. The thermal gravimetry and thermal differential analysis (TG-DTA) were... 

Thermal characteristics Thermal gravimetry and titrimetry differential scanning calorimetry differential thermal analyses thermal conductometric methods... 

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