Investigation of the Effect of Structuring Methods on the Change in Residul Stresses in Polymer Composite Material

Abstract

The process of forming the cohesive strength of PCM is associated with a decrease in its volume. If there is no mechanical impact on the material, then this process is called shrinkage. Shrinkage occurs during cooling, when the solvent evaporates and during structuring. The free shrinkage of the PCM is hindered by its adhesive bond with the surface of the product, which is filled with a polymer compound, as a result of which more or less shrinkage stresses develop in the PCM over time. In addition to the latter in the PCM there are thermal internal stresses. Their occurrence is due to the combination of different materials in PCM, which differ significantly in the coefficients of thermal expansion. An effective way to reduce internal stresses is to add to the composition of PCM various fillers and plasticizers, what improves the relaxation properties of PCM. The aim of this work was to study the influence of different methods of structuring (polymerization), i.e. by convection and in the field of high frequency currents of epoxy, acrylic and epoxyacrylic PCM. The study of the emerging internal stresses, both shrinkage and temperature, was performed by the method of digital strain gauge, which allows not only to record the final level of residual stresses, but to monitor it in the process of structuring. The studies have shown that a more effective method of structuring is the process of structuring in the field of high-frequency current, which reduces residual stresses, increases the modulus of elasticity and forcing temperature of the studied compounds, what increases the strength and performance properties of PCM, and significantly reduces structuring time, providing uniform heating over the whole volume of PCM. It is recommended to use the obtained data in various industries related to the process of gluing and sealing both homogeneous and heterogeneous materials, as well as PCM products