Hypothesis: Considering the properties and many applications of epoxy resins in the industry, cycloaliphatic structure in these resins can improve the chemical physical, mechanical and electrical properties of epoxy systems. The aim of
this research is the synthesis of cycloaliphatic epoxy resins of bi-functional diglycidyl 4-cyclohexane-1,2-dicarboxylate (Cyclo-2F) and tri-functional diglycidyl-4,5-epoxycyclohexane
1,2 dicarboxylate (Cyclo-3F) and studying the effect of a number of
epoxy functional groups and the type of placement of the cycloaliphatic ring on the final properties
Methods: To achieve this goal, tetrahydrophthalic anhydride was used as the raw material and the synthesis was done with epichlorohydrin and TCCA. In this researchtwo epoxy resins (bi-functional and tri-functional) have been synthesized, also, the effect of adding NaOH as a solid or solution to the reaction medium to close the epoxy
ring was investigated. The synthesis steps were investigated and confirmed using FTIR, ¹H-NMR and epoxy equivalent weight (EEW) analyses. To check the final properties, the synthesized resins were cured with m-phenylenediamine (m-PDA) and analyzed by TGA, DSC, tensile and DMTA analysis.
Findings: Due to the presence of ester groups in the main structure, the Cyclo-2Fepoxy resin has relatively good modulus and strength, but because the cycloaliphatic structure is not placed in the cured network by hanging out, it practically does not contribute much to the process of transferring stress and improving properties. While
in the Cyclo-3F resin, the presence of the epoxy group on the aliphatic ring causes this structure to be placed in the cured network, and in addition to increasing the density of crosslinks, it can withstand the introduced stress and external energies into the composite. If the synthesized tri-functional cycloaliphatic epoxy resin is cured with
m-phenylenediamine, it has a tensile modulus of 5.3 GPa, which has improved by more than 50% compared to conventional bisphenol epoxy resins.