Assessment of Epoxy Functionalized Poly(dimethylsiloxane) Vitrimers Catalyzed with Covalently Attached Amines as Reversible Adhesives

Abstract

AbstractIn this work, vitrimeric elastomers based on functionalized poly(dimethylsiloxane) are realized. By exploiting reactions of epoxide functional groups with carboxylic acids in the presence of a covalently bonded amine catalyst, dynamic networks are formed to establish their potential in reversible adhesives. The dynamic nature of the networks is characterized thermo‐mechanically, and in tensile tests 85% of the stress at break can be recovered after reprocessing. The covalent adaptable networks are further subjected to damp heat tests, temperature cycling tests, and high temperature storage with the aim to establish the potential and boundaries of the dynamic character of the network after application in harsh environments. The influence of the ageing tests on the reprocessability and mechanical properties is evaluated via infrared spectroscopy and lap‐shear tests. While the damp heat tests (85 °C, 85% relative humidity, and 2000 h duration) lead to hydrolytic bond cleavage of the ester bonds and storage at 120 °C for 930 h oxidizes the hydroxy groups, temperature cycling tests (−40 to 85 °C, 50 cycles) does not degrade the mechanical properties and the dynamic nature of the networks and rejoined lap‐shear specimen exhibit a remaining bond strength of more than 70%.