Eco-friendly polymers - vitrimers combine the advantages of thermosets and thermoplastics


With Paris Climate Agreement, signed by 195 countries, at the latest, the course has been set for a more conscious and resource-saving approach to our environment. In order to achieve the objectives of a maximum global warming of 2 °C compared to pre-industrial values, innovative technologies and materials must be developed, whereby their processing also plays an essential role. It is important to notethat the best solution for climate protection is not to be found in one specific approach but rather in a synergetic combination of individual innovations complementing each other.

Vitrimers provide the potential for these constitutions. These have unique properties that which are especially interesting in combination with load-bearing fiber. In principle, vitrimers have good mechanical properties, equivalent to most thermoset polymers which are already used in many industries. In contrast to thermosets, vitrimers can also be thermoformed or welded after stimulation by temperature due to their dynamic-chemical bonds. This was previously reserved for thermoplastics. The combination of good mechanical properties with those of further processing and reprocessability opens up new possibilities for the efficient production of high-performance components that require less energy and have short cycle times. Vitrimers also have the advantage over thermoset polymers in terms of recyclability (as they can be recycled both with special solvents and mechanically by grinding) and subsequent consolidation at temperatures above the glass transition temperature (Tg). As with thermoset polymers, 100% bio-based polymer systems are also possible with vitrimers.

In the project Airpoxy (, a Vitrimer system based on an epoxy with dynamic disulfide bridges and a service temperature above 130 °C (Tg = 170 °C) is reinforced with carbon fiber fabric. The aim is to develop a fiber reinforced composite based on vitrimers (Vitrimer FRPC) whose outstanding properties also make it suitable for aerospace applications. In addition to the material itself, the project also focuses on the manufacturing and processing procedures. For example, it is to be shown that Vitrimer FRPC - like thermoplastic FRP - can be thermoformed, welded and repaired. In order to determine suitable processing approaches and parameters for subsequent transfer to industrial scale for demonstrator manufacturing, these processes were initially developed and researched on a laboratory scale at Leibniz-Institut für Verbundwerkstoffe (IVW). In thermoforming for example, the high matrix viscosities of vitrimers pose the greatest challenge. The viscosities play a decisive role since they decisively allow the fabric layers to slide off each other and this is a basic prerequisite for thermoforming. Through a smart selection of suitable target geometries and an adapted process control, it is possible to induce a fabric ply sliding and thus also to produce thermoformed parts with Vitrimer FRPC. In welding, the major challenge is to achieve full-surface contact between the joining partners. This is necessary for the dynamic disulfide bridges to be able to find a bonding partner at the second joining partner – so that a chemical bond can be formed across the joining interface after cooling. It was shown that good joint strengths can be achieved by welding.

The interdisciplinary project consortium of eleven partners from six countries is confident that fiber-reinforced vitrimers will continue to establish their importance on the market in the future and that the materials and their processes can be further optimized in follow-up projects in order to establish market acceptance.

Currently, the project is in the process of being transferred from laboratory scale to industrial scale, where demonstrator parts are being manufactured. This is, for example, the leading edge of an aircraft wing which is welded with reinforcing ribs made of thermoformed Vitrimer FRPC. The outer skin of the leading edge is produced using the SQRTM (Same Qualified Resin Transfer Molding) process. The special feature is a functional layer made of a thin Vitrimer film which is also processed in the SQRTM process and acts as an intermediate welding layer.


The project is funded under grant agreement No. 769274 from the European Union Horizon 2020 research and innovation program.

Further information:

Dipl.-Ing. Stefan Weidmann
Scientific Staff Press- & Joining Technologies
Leibniz-Institut für Verbundwerkstoffe GmbH
Erwin-Schrödinger-Straße 58
Telefon: +49 631 2017-383

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