Heliyon (Apr 2023)
Structural features and mechanism of crystallization of nanocomposites based on maleinated high density polyethylene and carbon black
Abstract
The results of studying the structural features of nanocomposites by electron microscopy, X-ray diffraction analysis, derivatography and stepwise dilatometry are presented. The kinetic regularities of crystallization of nanocomposites based on Exxelor PE 1040-modified high density polyethylene HDPE* and carbon black (CB) are considered by the method of stepwise dilatometry: the dependence of specific volume on temperature. Dilatometric studies were carried out in the temperature range of 20–210 °C. The concentration of nanoparticles was varied within 1.0, 3.0, 5.0, 10, and 20 wt%. In the process of studying the temperature dependence of the specific volume of nanocomposites, it was found that a first-order phase transition occurs for HDPE* samples with 1.0–10 wt% CB content at 119 °C, and for a sample with 20 wt% CB at 115 °C. The study of the process kinetics of nanocomposites isothermal crystallization showed that, for nanocomposites with 1.0–10 wt% CB content, the mechanism of the process is characterized by the formation of a three-dimensional spherulite structure with continuously formed homogeneous and heterogeneous nucleation centers. A substantiated theoretical analysis and interpretation of the discovered regularities of the crystallization process and the growth mechanism of crystalline formations is given. Derivatographic studies of nanocomposites were carried out, according to which the features of changes in the thermal-physical properties of nanocomposites depending on the content of carbon black were established. The results of X-ray diffraction analysis of nanocomposites with 20 wt% carbon black content are presented, according to which there is a slight decrease in their degree of crystallinity.
