Ionic liquids as latent hardeners and multifunctional modifiers for epoxy systems

Technological Overview

A Polish research organisation has developed a group of ionic liquids designed to act as latent hardener and multifunctional modifiers for epoxy systems.

The solution is based on the use of ionic liquids as latent hardeners. Unlike conventional amine hardeners, these compounds remain chemically inert at room temperature, and the curing process is initiated after a precisely defined thermal stimulus is applied. This latency may enable one-component formulations with extended storage stability and a wider processing window. The developed systems effectively cure epoxy resins across a wide temperature range, from 50°C up to 250°C, which allows the curing profile to be matched to the resin system, the application and the processing technology.

In addition to initiating polymerisation, the ionic liquids remain within the resin or composite structure as multifunctional additives. Depending on their tailor-made structure, they can enhance mechanical, thermal or flame-retardant properties of the cured material, reducing the need for separate additives.

The systems show high dosage efficiency: in optimised formulations, only 2–3 wt% of the ionic liquid is needed, compared to 97–98 wt% of the resin. The curing systems have been optimised using widely available, commercial-grade epoxy resins (e.g. DGEBA-based), which could facilitate their implementation in existing formulations and supply chains.

Advantages and innovations

The proposed technology offers the following advantages and innovative aspects:

• latent curing: ionic liquids remain chemically inert at room temperature, and curing is initiated after a defined thermal stimulus;

• potential for one-component epoxy formulations with extended storage stability and a wider processing window;

• effective curing of epoxy resins across a wide temperature range, from 50°C up to 250°C;

• curing temperature and kinetics adjustable through the tailor-made structure of the ionic liquid, to match the resin system, application and processing technology;

• dual functionality: ionic liquids initiate polymerisation and remain in the resin or composite structure as multifunctional additives;

• reduced need for separate functional additives;

• high efficiency at low dosages: in optimised formulations, only 2–3 wt% of the ionic liquid per 97–98 wt% of the resin;

• systems optimised using widely available, commercial-grade epoxy resins facilitating implementation in existing formulations and supply chains;

• scale-up readiness, with the possibility to produce ionic liquids in batches of up to 100 kg;

• suitability for further laboratory and pilot-scale validation and technology transfer towards industrial applications.

Our Organization

Poznan Science and Technology Park (PPNT) is the first science and technology park in Poland, established in 1995 and operating within the Adam Mickiewicz University Foundation. We bridge the gap between academic breakthroughs and industrial application. As a research and technology organisation, we work in organic chemistry, advanced materials development and agrochemistry.

Our expertise includes:

• Design and synthesis of ionic liquids: tailor-made latent hardeners and functional modifiers for epoxy systems.

• Application-oriented formulation: tuning of curing temperature and kinetics, optimisation of epoxy systems and composites, including dosage and compatibility studies.

• Material characterization: curing behaviour and thermal, mechanical and flame-retardant properties of cured materials (DSC, DMA, TGA, LOI, PCFC).

• Scale-up excellence: laboratory-scale synthesis and scale-up of production up to 100 kg per batch.

• Validation and technology transfer: support in laboratory- and pilot-scale validation and transfer towards industrial applications.

• Science dissemination and popularization: organizing conferences, workshops and trade fairs.

Collaboration

We are looking for projects to join as research institution and consortium partner.