Establishing Patterns in the Structure Formation of Polymer Nanocomposites Based on Polyamide 6 During Their Crystallization Processes

Abstract

This paper reports experimental and computational studies on patterns in the structure formation of polymer nanocomposites when different types of fillers are used. The study was conduct-ed for nanocomposites based on poly-amide 6 filled with carbon nanotubes or silicon dioxide nanoparticles. In the course of research, the mass fraction of the filler varied from 0.2 % to 4.0 %, and the cooling rate of the melt composite varied from 0.5 K/min up to 20 K/min.Data on experimental and theoreti-cal studies into the mechanisms of struc-ture formation of composites accord-ing to the method, which includes two stages, are given. According to the first stage, crystallization exotherms of nanocomposites were experimental-ly obtained when they are cooled from the melt at a given constant rate. The dependence of various characteristics of the crystallization process on the mass fraction of the filler and the cooling rate of the composite was established.At the second stage, based on the analysis of the obtained crystallization exotherms, theoretical studies were per-formed to determine the mechanisms of structure formation of nanocompos-ites at different stages of crystalliza-tion. For the initial stage, according to the nucleation equation, the presence of two mechanisms of structure forma-tion – planar and volumetric – has been shown.Within the framework of the Kolmogorov-Avrami equation, the mechanisms of structure formation at the next stage of crystallization were established, which corresponds to the formation of ordered structures in the material within the volume of the poly-mer composite as a whole. The research was carried out assuming the existence of a mechanism of crystallization of the polymer matrix itself, which is real-ized on fluctuations in the density of the polymer, and a mechanism of crystal-lization, the centers of which are filler particles.The use of the proposed nano-composites is promising for the man-ufacture of parts of energy equipment, electronic equipment, elements of chemical, processing, defense indus-try installations, etc.