Decomposition by TGA

TA Instruments, Inc. (1995a). Thermal Analysis and Rheology Analysis of Polymer Decomposition by TGA-Mass Spectrometry, New Castle, DE. 

The decomposition by TGA was studied.9 In an inert atmosphere it occurs in two steps an endothermic decomposition in the range 200 to 310°C,... 

Very little is known about this salt. It has been prepared by treating the chloride with AgN02 and measuring decomposition by TGA.56 It occurs in two stages, the first one beginning at about 110%C being consistent with the stoichiometry... 

As reported, the thermal decomposition behaviour of amino trimethylene phosphonic acid (ATMP) and l-hydro)yethylidene-l,l-diphosphonic acid (HEDP) have been studied and a comparison of the experimental results from thermal decomposition by TGA-FTIR and pyrolysis GC-MS, together with modelling of the formation reactions, showed the usefulness of the latter method in predicting the possible decomposition products. Thus, pyrolysis GC-MS was used to determine the gaseous decomposition products of ATMP and HEDP at temperatures corresponding to the main decomposition steps detected by TGA-FTIR spectroscopy and, from a comparison of the experimental results with theoretical modelling, it was established that the decomposition process should follow the formation mechanism, i.e. the thermal decomposition can be understood as the reverse reaction of phosphonic acids. 

Ngo et al. [24] have shown that the thermal decomposition of ionic liquids, measured by TGA, varies depending on the sample pans used. Increased stabilization of up to 50 °C was obtained in some cases on changing from aluminium to alumina sample pans. 

Closely related mixed amido/imido/guanidinato tantalum complexes of the type Ta(NR R )[(R R2N)C(NR )2]( = NR ) (R R = Me, Et R = Cy, Pr R = Pr", BuO were synthesized by the insertion of carbodiimides into to tantalum-amide bonds in imidotantalum triamide precursors, and the effects of ligand substitution on thermal properties were studied by TGA/DTA measurements. In addition, selected compounds were pyrolyzed at 600 °C and the decomposition products were studied by GC-MS and NMR spectroscopy. ... 

The phosphazene backbone has a particularly high resistance to thermal treatment and to homolytic scission of the -P=N- bonds, possibly due to the combination of the high strength of the phosphazene bond and its remarkable ionic character [456]. As a consequence, the onset of thermal decomposition phenomena (as detected, for instance, by TGA) are observed at considerably high temperatures for poly[bis(trifluoroethoxy)phosphazene], [NP(OCH2CF3)2]n [391, 399, 457], for phosphazene copolymers substituted with fluorinated alcohols of different length [391, 399, 457], for polyspirophosphazenes substituted with 2,2 -dihydroxybiphenyl groups [458], and for poly(alkyl/aryl)-phosphazenes [332]. 

The solid-state decomposition of OV[OSi(O Bu)3]3 occurs with a precipitous weight loss at ca. 200 °C (as observed by TGA) and a final ceramic yield that is 10% less than the expected ceramic yield [79]. This discrepancy results from volatihzation and loss of HOSi(O Bu)3. However, solution thermolyses of OV[OSi(O Bu)3]3 in n-octane produce xerogels with an approximate composition of V2O5 6Si02 (after drying) with a quantitative ceramic yield (i.e., with no loss of HOSi(0 Bu)3) that have a BET surface area of 320 m g ... 

Thermal decomposition of Fe[0Si(0 Bu)3]3(THF) occurs at ca. 140 °C (by TGA) to provide a material with a lower ceramic yield (25.9%) than that calculated for FeOi.5 3Si02 (30.7%), suggesting potential loss of HOSi(0 Bu)3... 

Thermal decomposition of [Cu0Si(0 Bu)3]4 in the solid phase begins at ca. 100 °C under argon (by TGA) and results in formation of an amorphous material until roughly 600 °C, at which temperature Cu metal was detected (by PXRD) [105]. Conversely, decomposition under oxygen led initially to a material with Cu crystalhtes and small amounts of CU2O and CuO, and subsequent heating beyond 800 °C resulted in oxidation of all the copper to CuO. 

FIGURE 1.4 Decomposition of (a) cobalt nitrate solution and (b) cobalt nitrate-mannitol solution, measured by TGA and DTA. 

Estimation of Polymer Lifetime by TGA Decomposition Kinetics, TA Instruments Thermal Analysis Application Brief TA-125, pp. 1-4. 

A series of 11 nitrobenzaldehydes was examined by TGA, DSC and ARC techniques. Only 5-hydroxy-2-nitrobenzaldehyde decomposed exothermally in an unsealed container, but all did so in sealed capsules, under dynamic, isothermal or adiabatic conditions, with evolution of much gas. Initial decomposition temperatures in °C (compound, ARC value, and DSC value at lOVmin, respectively, followed by ARC energy of decomposition in kJ/g) were - 2-nitro-, 176, 220, 1.44 3-nitro-, 166, 218, 1.94 4-nitro-, 226, 260, 1.27 2-chloro-5-nitro-, 156, 226, 697 2-chloro-6-nitro-, 146, 220,. 832 4-chloro-3-nitro-, 116, 165, 1.42 5-chloro-2-nitro-, 240, 3-hydroxy-4-nitro-, 200, 4-hydroxy-3-nitro-, 200, 5-hydroxy-2-nitro-, 175, 3-methoxy-4-nitrobenzaldehyde, 245°C, -. 4-Nitrobenzaldehyde showed by... 

Thermal decomposition temperature determined by TGA. Anodic stability limit determined by cyclic voltammetry. Stainless steel working electrode. Number of fluorine substituents on the aromatic ring. 

Under the DSC conditions (N, scanning rate = 10°C/min), it is apparent that the decomposition processes are occurring at a much faster rate at or near the temperature at which cure is taking place in all the pure dlcyanate samples. Both BADCy and THIOCy showed small exotherms (onset at 277°C and 226°C and peak at 308°C and 289°C, respectively). Their major decompositions began about 251°C and 246°C, respectively, as observed by TGA. On the contrary, all the 1 1 BCB/dlcyanate blends displayed the expected thermal transitions. Besides initial Tg s (20-28°C) and Tm s (171-183°C), all samples showed small exotherms in their DSC scans with maxima at 147-151°C. This is attributable to the thermally-induced crystallization in the mixtures, which also led to some initial phase separation. The polymerization exotherms are consistent with the typical temperature ranges for the known benzocyclobutene-based systems (onset 229-233°C max. 259-266°C). 

Terpolymers of maleic anhydride (MA) and PPC could be prepared using a double-metal cyanide (DMC)-type catalyst. The polymer was amorphous like most terpolymers of propylene carbonate [39]. For terpolymers with up to 50 50 (mol/ mol) of PO/CO2 and MA, it could be shown by TGA that the observed degradation temperature was again raised by about 20-30°C and that the maximum rate of decomposition even exceeded 300°C. 

Initial studies were performed with [f-Bu2GaSbEt2]2 (3). DSC studies showed 3 to decompose in two steps around 190 and 215 °C as was confirmed by TGA/DTA experiments (Fig. 12) [36]. The first mass loss of almost 37% is only slightly larger than the calculated mass loss due to the elimination of two Ga-(t-Bu) groups (34%). Between 200 and 220 °C, an additional 9% mass loss was observed. Finally, a third mass loss of about 4% takes place above 500 °C, that most likely results from some decomposition of the material formed. 

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