Novel cyclopentane derivative as cross-linker vitrimer: Effect of catalyst contents on the mechanical property and chemical-recyclable ability

Abstract

A series of epoxy-based vitrimer were synthesized from diglycidyl ether of bisphenol A (DGEBA), sebacic acid (SA) and 3-(carboxymethyl)cyclopentane-1,2,4-tricarboxylic acid (TCAA) with 1,5,7-triazabicylo[4.4.0]dec-5-ene (TBD) as catalyst. Samples that contained only SA showed elastomer-like behavior, which exhibited low mechanical properties and high elongation at break. With the incorporation of SA:TCAA to 2:1, a feature transform from soft to hard was observed, the tensile strength increased from 40 to 70 MPa, the elongation at break decreased from above 200 to 20%, and the values of shore D hardness were also enhanced from 60 to 80. However, the TCAA with rigid structure hindered the transesterification rate, resulting in decreased stress relaxation efficiency. With the TCAA content increased, the stress relaxation time was extended further, while no mechanical properties enhancement was obtained, which might be due to the relatively low extent of reaction in synthesis caused by the steric effect of a higher concentration of TCAA. The effect of concentration for catalyst was also investigated. The stress relaxation efficiency enhanced with the TBD content increased while the thermal stability and mechanical properties decreased. With TBD concentration above 10%, SA:TCAA = 1:0 and 2:1 samples could be dissolved into ethylene glycol (EG) under 180 °C within 300 min, which shows potential for recyclable epoxy vitrimer composite applications.