Abstract: Here we examined binders based on ED-20 epoxy resin and Ethal amine-type hardeners (Ethal-23Х, Ethal-М7, Ethal45М). This study aimed to explore the chemical stability of the binders. Tests were performed by boiling in water and in 10% NaOH
solution for 3 h. The samples of all types were fabricated as dumbbell-shaped specimens as per GOST R 11262-2017 and were split
into three groups. Group I was not subjected to any corrosive medium (to determine the original strength of the binders), group II was
exposed to boiling in water for 3 h, and group II was held in 10% NaOH solution for 3 h at 95 °С. The results from tensile tests
pursuant to GOST R 11262-2017 showed that the residual strength of the binder specimens based on different hardeners after boiling
in water was as follows: 68.4 % (69.4 MPa original strength, 47.5 MPa after boiling) with Ethal-23Х, 73.1 % (69.5 MPa original
strength, 50.8 MPa after boiling) with Ethal-М7, and 81.2 % with Ethal-45М (48.9 MPa original strength, 39.7 МПа after boiling).
The maximum weight gain in this case was 1.3 %. The weight gain was below 1% after holding in 10% NaOH for 3 h at 95 oС, while
the residual strength of the binder specimens in tension was 68.6 % with Ethal-23Х (47.6 MPa strength after holding), 73,4 % with
Ethal-М7 (51.0 MPa strength after holding), and с 72.4 % with Ethal-45М (35.4 MPa strength after holding).
Index terms: epoxy binders, amine hardener, Ethal-45М, Ethal-М7, Ethal-23Х, chemical durability, boiling, NaOH solution, corrosive medium, strength, tension.