Phase Equilibrium, Morphology, and Physico-Mechanics in Epoxy-Thermoplastic Mixtures with Upper and Lower Critical Solution Temperatures.

Alexey V Shapagin,Nikita Yu Budylin,Vitaliy I Solodilov,Arkadiy A Poteryaev,Roman A Korokhin,Anatoly E Chalykh

doi:10.3390/polym13010035

Alexey V Shapagin, Nikita Yu Budylin + Show 4 more

Open Access

https://doi.org/10.3390/polym13010035

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Abstract

The mutual solubility of epoxy oligomer with polysulfone (PSU) and polyethersulfone (PES) was studied by optical interferometry. Additionally, phase diagrams (PDs) were plotted and their evolution during the curing process was shown. The phase structures of modified hardened systems, as well as their tensile strengths, elastic moduli, and crack resistance, have been studied by scanning electron microscopy and physico-mechanical techniques. The effect of initial components’ mutual solubility on the phase structure and, subsequently, on the physico-mechanical properties of the composite material is shown. Differences in the structure and properties of the cured modified compositions depending on the type of PD (with Upper Critical Solution Temperature (UCST) for PSU and Lower Critical Solution Temperature (LCST) for PES) of the initial components are shown.

Highlights

The development of the aerospace, automotive, and construction industries leads to the increase in the requirements for polymer binders for composite materials
We have shown that parameters of the critical point of a phase diagram (PD) and its distance from the curing isotherm determine the type of the forming phase structure and sizes of the phases [14,15]
The properties of heterogeneous systems are dependent on the mutual solubility and translational mobility of the components and kinetics of the chemical reaction, which affect the formation of the phase structure of the composite material and their properties [8,9,10,11,12,15,16,17,18,19,20,21]

Summary

Introduction

The development of the aerospace, automotive, and construction industries leads to the increase in the requirements for polymer binders for composite materials. The current paper is devoted to studying the effect of the solubility of the components before and during curing reactions of epoxy–TP systems on the structure of the cured composition as well as establishing a correlation between the main physical and mechanical properties and the phase structures of cured epoxy systems modified with polysulfone (PSU) and polyethersulfone (PES). The results of the study are of great importance for technologists when selecting composition of the binder to obtain the required structure of the cured matrix, which determines the maximum physical and mechanical characteristics of the products used in aerospace, automotive, and construction industries

Experimental

Results andand

Morphology of the mixture

Physico-Mechanical Properties

12. Concentration

Conclusions