Physical and chemical characteristics of local dissipative losses in polymethylmethacrylate

Resumo

The review deals with issues related to the theoretical analysis of the main relationship between the chemical structure of polymer and the response of various structural elements of this system to external mechanical effects at different temperatures and frequencies. The analysis is performed using the spectra of internal friction of unplasticized and plasticized polymethylmethacrylate (PMMA) obtained by dynamic methods of external deforming effects in the frequency range from 10^–2 to 10³ Hz and a temperature range of–50 to +250°C. The regions of local inelasticity are found, and the mechanisms of dissipative losses manifested in different temperature ranges of the spectrum are determined. The physical and chemical characteristics are calculated for each of the identified relaxation processes, and the dependence of these characteristics on molecular weight is found.