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Non-isothermal thermogravimetry of polymer

I. General model involving formal termination of active centres

Journal of Thermal Analysis and Calorimetry
Authors:
J. Rychlý
and
L. Rychlá

A Model of polymer decomposition is proposed which formally involves the termination of active centres. It yields reasonable activation energies for the decompositions of polypropylene, polyethylene, polystyrene and polymethyl methacrylate investigated by non-isothermal thermogravimetry. In the value of a formal reaction orders the model reflects the reaction conditions, such as initial sample weight, atmosphere, ventilation conditions, sample holder nature and shape, etc.

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Nonisothermal thermogravimetry of polymers

IV. Polyethylene and ethylene-vinyl acetate copolymers highly loaded with Al(OH)3 and Mg(OH)2

Journal of Thermal Analysis and Calorimetry
Authors:
J. Rychly
,
A. Dalinkevich
,
I. Janigová
, and
L. Rychlá

Abstract  

The decomposition of polyethylene and ethylene-vinyl acetate copolymers in composites with Al(OH)3 and Mg(OH)2 (60% by wt.) has been estimated from the aspect of the extent of synchronization of the two fundamental processes, the release of water and flammable volatiles from a polymer and the effect of this on the resulting polymer flammability. An attempt has been made to implement the peculiarities of decomposition observed for each system to the fire behaviour of these materials.

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DSC study of the decomposition of azodicarbonamide in different media

I. Decomposition of pure azodicarbonamide; the search for the kinetic model

Journal of Thermal Analysis and Calorimetry
Authors:
L. Rychlá
,
J. Rychlý
,
J. Svoboda
, and
J. Šimonik
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A new differential method of evaluating integral thermogravimetric records of the formation of volatile products during the degradation of polypropylene in air is presented. The method, applied to 0–100% conversion of the polymer to volatile products, may distinguish the initial presence of low molecular compounds in the polymer, as well as changes in the mechanism of degradation of the material.

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Abstract  

The application of solution microcalorimetry was demonstrated on two model examples – inhibited oxidation of cumene and radical polymerization of styrene.From the experimental dependences of the rate of heat release on time, the rate constants k 7 of the interaction of an inhibitor with radicals of substrate (RO 2 . or R.) in oxidation or in polymerization were determined for the set of inhibitors of N-aryl N-(2-quinone) amine series. It was shown that these compounds are weak inhibitors of oxidation of cumene and rather efficient inhibitor of polymerization of styrene.

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