A New Thermally Re-Mendable and Recyclable Epoxy Thermoset Based on Siloxane Equilibration

Abstract

A new thermally re-mendable and recyclable epoxy thermoset was developed from diglycidyl ether of ethoxylated bisphenol-A (DGEBAEO) and bis (potassium) oligoaminopropylmethylsiloxanediolate (K-PAMS). The DGEBAEO/K-PAMS system was a highly crosslinked thermoset with Tg of 75 oC and elastic modulus about 2.2Gpa (Figure 1). K-PAMS contained active potassium aminopropylmethylsilanolate end groups that can catalyze the siloxane equilibration to restructure the crosslink network, enabling the fractured thermoset to be self-healed and the pulverized thermoset grains to be reprocessed like thermoplastics under elevated temperature (about 110 oC) (Figure 2). The healing efficiency of tensile strength achieved 80% after 24 h healing and the recyclable specimen showed fully recovery in storage modulus.