Predictive capability studies of relaxation nature of thermal degradation of polymers

Аuthors

Zadorina E. N.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: zadorina_e@mail.ru

Abstract

The author first proposed to consider the process of thermal degradation of polymers as a kind of process of physical-chemical relaxation. The process has two components: chemical, due to the rupture of chemical bonds and physical, associated with the movement of the structural units of the polymer. In this case, the so-called apparent or effective, kinetic characteristics of the process — the pre-exponential factor, activation energy and reaction order — purchase a specific physical meaning. Easy to overcome the energy barrier of a chemical reaction is preceded by the movement of the respective nanostructured polymer units, that is ongoing in parallel with other processes, with nature and relaxation which also requires a certain energy.

Calculation of kinetic parameters is important not only for the formal description of the process, but also to obtain data on the structure of the polymer. For this purpose it was proposed to consider the process of thermal degradation of the PM as kinetic plane described by the three parameters. Defining segments, that the kinetic plane trims on the coordinate axes X, Y, Z, and the angles formed, it is possible to calculate the kinetic parameters of thermal degradation process of the polymer.

The author introduced the concept of the relaxation time of thermal degradation of the polymer τ_р. Asked to count it as a time of transition of the polymer fr om the initial equilibrium state to equilibrium state corresponding to the high-temperature heating conditions: ( T_f—T_i)/b wh ere T_i and T_f is the temperature of the beginning and end of the thermal degradation process, b is the heating rate, K/s.

This approach allows us reliably interpret experimental results and to predict the thermal behavior of polymeric materials at high speeds heating. Specialists receive information, allowing the use of nanotechnology for targeted development of the nanostructure of polymer materials heatproof destination. On the other hand, the creation of nanostructured polymers and polymer composites is achieved processes of thermodestruction management. Of special interest, relaxational nature of thermal degradation of polymers should cause researchers stress-strain states of polymeric composite materials, working in conditions of high temperature heating and used to create structural elements of modern aerospace.

Keywords:

thermal decomposition of polymers, kinetic plane, the relaxation time of thermal decomposition, high-speed heating of the polymers

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