Change of epoxy polymer properties after mold fungi influence depending on initial epoxy resin structure | Mekhanika | kompozitsionnykh | materialov i konstruktsii
> Volume 26 > №4 / 2021 / Pages: 528-543

Change of epoxy polymer properties after mold fungi influence depending on initial epoxy resin structure

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Abstract:

The reaction activity of mixtures based on epoxy resins of bisphenol A as well as 4,4′-methylenedianiline tetraglycidyl ether with an amine hardener were studied. The gelation of the mixtures was determined. The curing reaction parameters of epoxy compositions are determined by differential scanning calorimetry. The temperature-time regime of specimen curing was selected by means of mathematical modeling implementing and the experimental data studying of the curing kinetics obtained the thermoanalytical method. Given regime was recommended for polymer matrices with a predictable high degree of reactive groups conversion obtaining. A mixture of bisphenol A diglycidyl ether epoxy oligomer (ED-22 brand resin) with an amine hardener was chosen as a model sample for mode selecting. When using the proposed mode, the degree of curing of epoxy matrices of all samples under study exceeded 90%. A high completeness of the reaction was suggested. The fungal resistance of epoxy polymers has been studied. Microstructural studies of the samples were performed by means of optical microscopy. The predicted damage of the samples surfaces of all epoxy matrices exposed to micromycetes was found. It could be associated with the frequency of polymer chains cross-linking, which directly depends on the value of the initial resin epoxy number. To assess the change in the characteristics of polymers after microbiological tests, the mechanical and thermal properties of the cured epoxy matrices were carried out. The research of heat resistance and static bending strength of samples after exposure to micromycetes was performed. The dependence of the change in the properties of epoxy polymers after tests for resistance to mold fungi on the frequency of cross-linking of polymer matrices was revealed.

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