Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation.

Michael Giebler,Simon Kaiser,Sandra Schlögl,Clemens Sperling,Ivica Duretek

doi:10.3390/polym12051148

Michael Giebler, Simon Kaiser + Show 3 more

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https://doi.org/10.3390/polym12051148

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Abstract

Epoxy-anhydride vitrimers are covalent adaptable networks, which undergo associative bond exchange reactions at elevated temperature. Their service temperature is influenced by the glass transition temperature (Tg) as well as the topology freezing transition temperature (Tv), at which the covalent bond exchange reactions become significantly fast. The present work highlights the design of high-Tg epoxy-anhydride vitrimers that comprise an efficient stress relaxation at elevated temperature. Networks are prepared by thermally curing aminoglycidyl monomers with glutaric anhydride in different stoichiometric ratios. The tertiary amine groups present in the structure of the aminoglycidyl derivatives not only accelerate the curing reaction but also catalyse the transesterification reaction above Tv, as shown in stress relaxation measurements. The topology rearrangements render the networks recyclable, which is demonstrated by reprocessing a grinded powder of the cured materials in a hot press. The epoxy-anhydride vitrimers are characterised by a high Tg (up to 140 °C) and an adequate storage modulus at 25 °C (~2.5 GPa), which makes them interesting candidates for structural applications operating at high service temperature.

Highlights

Epoxy resins have a wide range of industrial applications but suffer from a lack of recyclability due to their permanently cross-linked network structure
This changed in 2011 due to the pioneering work of Leibler and his group, who introduced epoxy-based vitrimers, which represent a new class of covalent adaptable networks (CANs) [1]
Epoxy-anhydride vitrimers were prepared using thermal of triand tetra-functional aminoglycidyl epoxy monomers with glutaric anhydride

Summary

Introduction

Epoxy resins have a wide range of industrial applications but suffer from a lack of recyclability due to their permanently cross-linked network structure. This changed in 2011 due to the pioneering work of Leibler and his group, who introduced epoxy-based vitrimers, which represent a new class of covalent adaptable networks (CANs) [1]. Tv , the network structure is frozen, whilst above Tv , the network is able to flow macroscopically and fully relax stresses, behaving like a viscoelastic liquid [3,4,5,6] This enables the introduction of new material properties in epoxy-based networks, such as self-healing and recyclability [7,8,9,10]

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