Thermal and thermooxidative degradation

Thermal, Thermooxidative, and Photooxidative Degradation. Polymers of a-olefins have at least one tertiary C-H bond in each monomer unit of polymer chains. As a result, these polymers are susceptible to both thermal and thermooxidative degradation. Reactivity in degradation reactions is especially significant in the case of polyolefins with branched alkyl side groups. For example, thermal decomposition of... 

Fig. 9. Thermal and thermooxidative degradation of PS. Viscosity is for a 10% solution in toluene at 25°C.

Polymers of a-olefins are susceptible to thermal and thermooxidative degradation. Reactivity in degradation reactions is especially significant in the case of polyolefins with branched alkyl side groups,... 

This volume is including information about thermal and thermooxidative degradation of polyolefine nanocomposites, modeling of catalytic complexes in the oxidation reactions, modeling the kinetics of moisture adsorption by natural and synthetic polymers, new trends, achievements and developments on the effects of beam radiation, structural behaviour of composite materials, comparative evaluation of antioxidants properties, synthesis, properties and application of polymeric composites and nanocomposites, photodegradation and light stabilization of polymers, wear resistant composite polymeric materials, some macrokinetic phenomena, transport phenomena in polymer matrix, liquid crystals, flammability of polymeric materials and new flame retardants. 

Kozlov, G. V. Shustov, G. B. Zaikov, G. E. The structural aspect of the interrelation of the characteristics of thermal and thermooxidative degradation of heterochain polyethers. In book Aging of Polymers, Polymer Blends and Polymer Composites. V. 2. Ed. Zaikov, G. Buchachenko, A. Ivanov, V New York, Nova Science Ihiblishers, Inc. 2002,151-160. 

For example, solid state polycondensation (SSP), a way to increase the molecular weight directly on pellets of solid PET, is the evidence that Sb(III) residual is still active in solid polymer. [25-28] On the contrary less information are available about the effect of Ti(IV) residual on SSP for PBT. It is a matter of fact that in all the studies about thermal and thermooxidation degradation, the effects of the eatalytic system are usually ignored because the catalyst is always present as residual in every PBT sample. It is simply a background effect. 

S-12 based samples show the best thermal- and thermooxidation degradation stability as well as UV-aging resistance. 

Apparent activation energy of thermal and thermooxidative degradation processes, as well as main decomposition temperatures in various enviromnents of compostable polymer materials, are summarized in Tables 4.1 and 4.2, respectively. 

Thermal and thermooxidative stability of synthesized ferrocene-containing polymers was studied by TGA method. It was found that thermal and thermooxidative degradation followed the basic features of such processes. Thus, the higher degree of decomposition in air was observed for all investigated polymers compared to that in... 

Pearce, E. M. et al. Fourier Transform IR Spectroscopy for the Study of Polymer Degradation, Thermal and Thermooxidative Degradation of Polyethylene Terephthalate, American Chemical Society (1983)... 

M.R Kharitonov and V.V. Ostrovsky, Thermal and Thermooxidative Degradation of Polyoxysiloxanes, Nauka, Leningrad, Russia, 1982. [in Russian]... 

A comparative study has been conducted into the thermal and thermooxidative degradation of PET and PBT polymer films and their model compounds, ethylene dibenzoate and butylene dibenzoate, in an oxygen atmosphere at 160 °C 832485. On the basis of the compounds identified by GC-MS, a mechanism was proposed for the degradation of the model compounds that involves oxidation at the a-methylene carbon with the formation of unstable peroxides and carboxylic acids a.l53. From the studies performed under N2 at 160 °C, it was concluded that benzoic acid and esters are products of the thermal degradation as illustrated in Schemes 15 and 16, while benzoic and aliphatic acids, anhydride and alcohols were due to thermooxidative degradation. 

The onset temperature of both thermal and thermooxidation degradation decreases due to UV-degradation proceeded not only within amorphous phase but also within crystalline phase, as said above. 

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