Design of self-healing catalysts for aircraft application

Abstract

Purpose

The purpose of this paper is to highlight the relevant role of the stereochemistry of two Ruthenium catalysts on the self-healing efficiency of aeronautical resins.

Design/methodology/approach

Here, a very detailed evaluation on the stereochemistry of two new ruthenium catalysts evidences the crucial role of the spatial orientation of phenyl groups in the N-heterocyclic carbene ligands in determining the temperature range within the curing cycles is feasible without deactivating the self-healing mechanisms (ring-opening metathesis polymerization reactions) inside the thermosetting resin. The exceptional activity and thermal stability of the HG2_MesPhSyn catalyst, with the syn orientation of phenyl groups, highlight the relevant potentiality and the future perspectives of this complex for the activation of the self-healing function in aeronautical resins.

Findings

The HG2_MesPhSyn complex, with the syn orientation of the phenyl groups, is able to activate metathesis reactions within the highly reactive environment of the epoxy thermosetting resins, cured up to 180°C, while the other stereoisomer, with the anti-orientation of the phenyl groups, does not preserve its catalytic activity in these conditions.

Originality/value

In this paper, a comparison between the self-healing functionality of two catalytic systems has been performed, using metathesis tests and FTIR spectroscopy. In the field of the design of catalytic systems for self-healing structural materials, a very relevant result has been found: a slight difference in the molecular stereochemistry plays a key role in the development of self-healing materials for aeronautical and aerospace applications.

Citation

Calabrese, E., Longo, P., Naddeo, C., Mariconda, A., Vertuccio, L., Raimondo, M. and Guadagno, L. (2018), "Design of self-healing catalysts for aircraft application", International Journal of Structural Integrity, Vol. 9 No. 6, pp. 723-736. https://doi.org/10.1108/IJSI-12-2017-0077