Temperature Areas of Local Inelasticity in Polyoxymethylene.

The spectra of internal friction and temperature dependencies of the frequency of a free-damped oscillation process excited in the specimens of an amorphous-crystalline copolymer of polyoxymethylene with the co-monomer trioxane (POM-C) with a degree of crystallinity ~60% in the temperature range from -150 °C to +170 °C has been studied. It has been established that the spectra of internal friction show five local dissipative processes of varying intensity, manifested in different temperature ranges of the spectrum. An anomalous decrease in the frequency of the oscillatory process was detected in the temperature ranges where the most intense dissipative losses appear on the spectrum of internal friction.

Relaxation Phenomena in Low-Density and High-Density Polyethylene.

A study was conducted on the internal friction spectra and temperature dependencies of the frequency of free damped oscillatory processes excited in the investigated samples of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) over a temperature range from -150 °C to +150 °C. It was found that the internal friction spectra exhibit several local dissipative processes of varying intensity, which manifest in different temperature intervals. The structure of the internal friction spectra and the peaks of dissipative losses are complex, as evidenced by the occurrence of sharp, locally temperature-dependent jumps in the intensity of dissipative losses observed throughout the entire temperature range.

Spectra of Internal Friction in Polyethylene.

The study of spectra of internal friction λ=fT and temperature dependencies of frequency of freely damped ν=fT oscillatory process excited in investigated samples of polyethylene with different degree of crystallinity in the temperature range from -150 °C to +150 °C. It is established that four local dissipative processes of different intensity shown in different temperature intervals are observed on the spectra λ=fT. These are μ, β, α, βk processes.