Thermal degradation studies

Thermal degradation studies of EB-cured terpolymeric fluorocarbon rubber [430] by nonisothermal thermogravimetry in the absence and presence of cross-link promoter TMPTA reveal that thermal stability is improved on radiation and more so in the presence of TMPTA. Initial decomposition temperature, maximum decomposition temperature and the decomposition... 

Thermal degradation studies might be required to determine the decomposition characteristics of of the subject pesticide vAien heated alone or In the presence of oxidizers and/or binders In both closed and open systems and at various temperatures. 

In conclusion thermal degradation studies on Nautilus pompilius indicate that mineralizing matrix and aragonite shell represent a true structural entity. By the sharing of oxygens in protein and mineral lattices we will generate phase boundaries of the type that are present, for instance, in the common clay mineral kaolinite. Here, aluminum octahedra and silica tetrahedra incorporate the same oxygens and hydroxyls, and layers composed of octahedra and tetrahedra arise (Fig. 13). 

K. A. Tehrani, M. Kersiene, A. Adams, R. Venskutonis, and N. de Kimpe, Thermal degradation studies of glucose/glycine melanoidins, J. Agric. Food Chem., 2002, 50, 4062-4068. 

This section discusses the thermal degradation studies conducted using a thermogravimetric analyzer (TGA). In general, the thermal stability of filled composites is better than pure polymers due to the presence of fillers, which act as stabilizing agents (73). In particular, the addition of CNTs present superior thermal stability for composites compared with neat polymers (90-92). 

Nadler, M. P. Thermal Degradation Study of IM7/DMBZ-15 High Temperature Composite by TGA/FTIR Technical Paper NAWCWD-TP-8568, Naval Air Warfare Center, Weapons Division, China Lake, CA 93555, Research Dept., September 2003. 

C. McNeill and M. Bounekhel Thermal degradation studies of terephthalate polyesters 1. Poly(alkylene terephthalates), Polym. Degrad. Stab., 34, 187-204 (1991). 

Thermal degradation studies of polysulphide sealants have shown the evolution of gases such as hydrogen sulphide, ethylene, sulphur dioxide and carbon dioxide, but the rate of evolution of these compounds was found to be below the level considered hazardous (Berenbaum, 1969). 

Pyrolysis of the formed polysilazane at 750° C generates several alkylsilanes such as dimethylsilane, trimethylsilane, ethyldimethylsilane, tetramethyidisiloxane, pentamethyidisiloxane, methylenebisdimethylsilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, etc. The presence of the cyclic compounds similar to those from poly(dimethylsiloxane) was an indication that some polysiloxane sequences may be present in the polymer. Thermal degradation studied between 350° C and 650° C showed the formation of some hydrogen, methane, ethane, and propene. 

Awada WH, Gilman JW, Nyden M et al. (2004) Thermal degradation studies of alkyl-imidazolium salts and their application in nanocomposites. Thermochim Acta 409 3-11... 

Whereas in our thermal degradation studies [113], PPY(Bp4) lost weight in three rather indistinct steps in... 

B.S. Kaith, and A.S. Singha, "Thermal degradation studies on some cellulose fibres and their derivatives" Proceedings of the 38th lUPAC Congress, Brisbane (Australia), 2001. 

Two remaining polymers have been encountered in the literature which fall under the category of silarylene polymers, but these polymers have no siloxane linkages. The first polymer which will be discussed has been used by Zelei and co-workers 22 as well as Ikeda and co-workers 23 in thermal degradation studies of 1 (poly(tetramethyl-p-silphenylenesilox-ane)). The polymer used was poly(p-dimethylsilphenylene) (101 and has been prepared by a method shown below. The second polymer is poly[l-(dimethylsilyl)-4-(dimethylethyl-ene)silylbenzene]) (H) and was prepared using a well known hydrosilylation mechanism in... 

McNeill, I. C. and Bounekel, M., Thermal degradation studies of therephthalate polyesters 1. Poly(alkylene terephthalate), Polym. Deg. Stab., 34,187,1991. 

The Am = 44 fragment series fits none of the products found or intermediates postulated in thermal degradation studies, but is consistent with earlier laser desorption work where the same series was observed in cation-ized form and attributed to tire random scission process... 

From thermal degradation studies it was shown that temperatures available in environmental conditiorrs ( 100°C) accelerate plasticizer diffusion. Thirs plasticizer loss may... 

The fundamental degradation chemistry of PET and PEN should be very similar. Actually, thermal degradation studies show strong similarities in the degradation behavior of these related polymers. Identical primary and secondary thermal degradation mechanisms have been proposed [63]. 

Differential scanning calorimetry [7] and thermogravimetric analysis [8] have also been applied to thermal degradation studies on EPDM. 

Various other works have discussed the application of MS and other techniques in thermal degradation. Studies have been made on a nnmber of epoxy resins [18-20] based on DGEBA. These inclnde tetraglycidyl ether tetrakis (hydroxyphenol) ethane [17], araldite-epoxy resins [18]. 

In a study of the flame retardance of styrene-methyl methacrylate copolymer with covalently bound pyrocatechol-vinyl phosphate, diethyl p-vinyl benzyl phosphonate, or di(2-phenyl ethyl phosphonate) groups. Ebdon and co-workers [23] obtained data on their decomposition behaviour. This was achieved by reducing the rate of liberation of flammable methyl methacrylate monomer during combustion. Possible mechanisms for these processes are suggested. Other methacrylate copolymers which have been the subject of thermal degradation studies include PMMA-N-methylmaleimide-styrene [24] and PMMA-ethylene vinyl acetate [25-27]. 

Several techniques have been used in thermal degradation studies on polyacrylates including TGA [25, 28-31, 35] and various procedures based on pyrolysis followed by MS. 

Other polymers which have been the subject of thermal degradation studies include ethylene-vinyl acetate [29, 66, 67], ethylene-vinyl alcohol [68], poly(aryl-ether ketone) [69], poly-2-vinyl-naphthalene-co-methyl maleate [34], polyphenylenes based on diethyl-benzophenone [70], polyglycollide [71-73], poly(a-methylstyrene tricarbonyl chromium [74], polytetrahydrofuran [75], polylactide [76-78], poly(vinyl) cyclohexane [79], styrene-vinyl cyclohexane [80], isopropenylacetate-maleic dianhydride [80], polyethylene glycol containing a 1,3-disubstituted phenolic group [81], poly-2-vinyl naphthalene-co-methacrylate [34], collagen biopolymers [82], chitin graft poly (2-methyl-oxazoline - polyvinyl chloride blends [83], cellulose [32, 83-88] and side-chain cholestric elastomers [89, 90]. 

M. Bounekhel and I. C. McNeill, Thermal degradation studies of terephthalate polyesters 3. 

The results represent the first thermal degradation study that has been conducted on well-defined polyphosphazenes. They also provide an unambiguous answer to the actual mechanism of degradation in these polymers. 

The performance of the two rotation modes also differed for peroxide-induced degradation. When a small quantity of peroxide was used (0.05 phr), the results were similar to the thermal degradation study. The extruder, when mn in counterrotating mode, achieved greater levels of degradation at all screw speeds studied. When the peroxide level was increased to 0.2 phr, the extent of the degradation reaction became high and insensitive to the mode or operation. This... 

A thermal degradation study by I.C. McNeill and D. Neil (McNeill and Neil, 1970) involving PVC/PMMA mixture yielded oidy hydrogen chloride and methyl... 

Temperature is one of the most important parameters to be specified, as viscosity is a strong function of temperature. The temperature must be high enough to melt the sample completely and low enough that the sample will not degrade during the test. Once a temperature is chosen, a thermal degradation study should be performed to determine the maximum residence time of the material in the rheometer. 

This equipment has, to date, been used for thermal degradation studies on PTFE and PVC, and filler, monomer, and plasticiser analyses in polymers. It is worth noting that while quantification from FT-IR spectroscopy results is feasible, there could be a discrepancy between the calculated weight loss of evolved gases and that found by TGA. This discrepancy can be accounted for by the evolution of a gas such as nitrogen which FT-IR spectroscopy is unable to detect. 

Poly(dimethyl/methylphenyl siloxane)s and poly(dimethyl/diphenyl siloxane)s have been prepared with a range of phenyl contents and their thermal degradations studied. The products of degradation are shown to be benzene and a complex mixture of cyclic oligomers, the latter being analysed by GLC, mass spectrometry, and n.m.r. spectrometry. The mechanism of degradation is discussed in relation to the degradation reactions previously described for (PDMS) and poly(methylphenyl siloxane)s. A study of soluble and insoluble heat stability additives for (PDMS) has been reported and a mechanism of stabilization proposed. ... 

Degradation behaviour. Similar interests to those discussed for polyesters have resulted in thermal oxidative and thermal degradation studies on polyamides. 

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