The effects of temperature on mechanical properties of neat and montmorillonite reinforced epoxy compounds

Abstract

ABSTRACT The aim of the article was to determine the effect of temperature on the tensile strength of two types of the epoxy compounds: the neat and the montmorillonite reinforced epoxy compounds. These epoxy compounds were made in four variants, which included two epoxy resins based on bisphenol A (unmodified base epoxy resin and modified with polyester resin epoxy resin) as well as two curing agents: triethylenetetramine and polyamide curing agent. The samples were exposed in two types of environment: (i) at 80°C for 1 and 2 months in a thermal chamber and also (ii) in the temperature range from −40°C to 80°C for 1 and 2 months in a thermal shock chamber. The reference samples of epoxy compounds were also compared. After the aging time, the dog-bone samples of epoxy compounds were subjected to the tensile strength tests in accordance with PN-EN ISO 527–2. The compressive strength of reference samples is higher for epoxy compounds containing the triethylenetetramine curing agent (both for epoxy compounds comprising Epidian 5 and Epidian 57 epoxy resin), The values of tensile strength, elongation at break are affected by the ambient and curing temperature, the curing period and the presence of a filler (montmorillonite). The tensile strength of the reference epoxy compounds containing Epidian 5 epoxy resin and the triethylenetetramine curing agent is lower than that of epoxy compounds containing unmodified epoxy resin (Epidian 5) and the polyaminoamide curing agent, while the tensile strength of the epoxy compounds containing modified epoxy resin (Epidian 57) and the triethylenetetramine curing agent is higher than that of the epoxy compounds containing Epidian 57 epoxy resin and the polyaminoamide curing agent. Aging of the epoxy compounds both in the climatic chamber and in the thermal shock chamber in most cases it contributed to an increase in the tensile strength.