Polyfire

The Polyfire project will develop and scale-up techniques for processing
halogen-free, flame retardant nanocomposite materials and coatings based on unsaturated polyester resins and nanoclays.

Unsaturated polyester resins are used extensively in fibre-reinforced composites and coatings because of their relatively low cost, good processability and balance of properties. However, one major disadvantage of these resins is their flammability - they ignite readily, burn vigorously and generate dense smoke during combustion.

The fire performance of polyester resins can be improved by using fire-retardant additives. The most common additives are halogenated compounds (containing chlorine or bromine), antimony-based systems and non-combustible fillers, such as aluminium trihydrate. However, halogenated systems generate large quantities of toxic and corrosive combustion products so tend to perform poorly in modern, more stringent tests. The halogen-free additives, such as alumina trihydrate (ATH) and ammonium polyphosphate, can overcome some of these problems; but must be used at high loadings to achieve a significant fire retardant effect. This reduces processability, reduces strength and impact resistance and increases weight. For these reasons, there remains a gap in the market for high-performance, halogen-free fire retardant polyester materials.

It is well-established that the addition of small amounts of well-dispersed, nano-sized particles to polymers can result in a simultaneous improvement of a range of mechanical and physical properties including fire retardancy. The improved fire retardancy has been attributed to the formation of a continuous, defect free char, which forms a barrier on the surface, protecting the unburnt polymer beneath. In order to obtain this char, good dispersion of the clay within the polymer is crucial. Mechanical mixing alone is not sufficient to achieve this dispersion and it is necessary to chemically modify the surface of the clay platelets, thereby improving their compatibility with the polyester resin.

The target of the Polyfire project is to develop and scale-up the nanoclay chemical modification process and the physical mixing and dispersion techniques which will deliver the production of halogen-free, fire-retardant polyester resin on an industrial scale (typically 1000 tonnes per year).

The materials developed will open up an extensive field of applications in a wide range of industrial sectors, not least construction and mass transport, where flame-retardancy and light-weight are critical. The project will focus on developing turn-key solutions that will be easily integrated into industrial companies, in particular SMEs in Western and Eastern Europe, thereby ensuring maximum impact and benefit to the European community.

Project Partners  

• NetComposites
• Laviosa Chimica Mineraria S.p.A
• Fundacion Gaiker
• YTRON Process Technology
• Scott Bader Ltd
• IRIS Vernici
• APC Composite
• FEPS
• Sheffield Hallam University
• Fundacion LEIA
• Procoat

Website:  www.polyfireproject.eu

Acknowledgments

The research leading to these results has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement 229220.