Study of polymer composites by methods of thermoactivated spectroscopy

Abstract

Variations in the temperatures of structural transitions and stabilization of charges depending on the degree of filling of low density polyethylene (LDPE) are studied by the methods of radiothermoluminescense (RTL) and thermally stimulated current (TSC). The RTL spectrum of the initial LDPE exhibits three maxima at temperatures of 130, 173, and 227 K (γ-, α-, and β-relaxation). The low-temperature maxima are assumed to be related to recombination of trapped electrons with products of radiolysis (radicals) and the relatively high-temperature peak at 228, to recombination of trapped electrons with luminescence centers after tunneling through a potential barrier. Modification of LDPE by introduction of a special additive (SA) in an amount up to 2 wt % shifts the γ- and α-peaks on the RTL curve to lower temperatures and the β-peak, to higher temperatures. The TSC spectrum exhibits two maxima at temperatures of 303 and 418 K, respectively. Modification of LDPE leads to a sharp decrease in the amplitude of both peaks and shifts the maxima to higher temperatures. The peak at 418 K is due to the release of trapped charges from traps in the crystalline phase of LDPE at melting.