Thermo-oxidative processes comparison

Introduction DMB leads to significant changes in processes thermo-oxidative decomposition the weight loss for copolymers is registered at lower temperatures (Fig. 2) and proceeds more intensively (Fig. 3). With the increase of temperature up to 300°C, as can be seen, the presence of DMB causes the reduction of the speed of weight loss. The speed of the smaller, more content maleic links. The endothermic peak of more than offset by a comparison with PVA, however, extends to a wider temperature field (200-350°C). 

The comparison of the results obtained in this study for the LCP degradation imder processing temperatures with the peculiarities of some thermally stable polyheteroaiylenes degradation [14] brings to light some common features carbonization of the structure, H2 evolution, improvement in thermo-oxidative stability with transition metal compoimds. That is why we took into accoimt the stabilization of polysulfones, aiyl-aliphatic polyimides, polyamides etc. The approach to such stabilization is based on the following proposals on the mechanisms of the above said polymer degradation ... 

To clarify the mechanisms of the clay-reinforced carbonaceous char formation, which may be responsible for the reduced mass loss rates, and hence the lower flammability of the polymer matrices, a number of thermo-physical characteristics of the PE/MMT nanocomposites have been measured in comparison with those of the pristine PE (which, by itself is not a char former) in both inert and oxidizing atmospheres. The evolution of the thermal and thermal-oxidative degradation processes in these systems was followed dynamically with the aid of TGA and FTIR methods. Proper attention was paid also to the effect of oxygen on the thermal-oxidative stability of PE nanocomposites in their solid state, in both the absence as well as in the presence of an antioxidant. Several sets of experimentally acquired TGA data have provided a basis for accomplishing thorough model-based kinetic analyses of thermal and thermal-oxidative degradation of both pristine PE and PE/MMT nanocomposites prepared in this work. 

From the point of view of practical application the thermo-decomposition reaction of alkoxides appears to be important [8, 9, 17, 33]. These processes proceed at 260-320°C and are utilized for the preparation of high purity REM oxides [54]. Derivatives of the fluorinated alcohol Ln[OCH(CF3)2]3 decompose at lower temperature (100-200°C) and afford fluorides LnF3 instead of oxides [30, 43]. The reason for it may be a higher bond energy of Ln-F bond in comparison with Ln-0 one. It has been found that the Pr-0 and Gd-0 bond dissociation energy is 179 kcal/mol and is somewhat lower for Sc-O (159 kcal/mol) and Eu-O (115 kcal/mol) [55]. 

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