Fire safety treatment of woodFire safety treatment of wood

Laia Haurie, Universitat Politècnica de Catalunya, presented tests of resin-impregnation of wood, with the objective of developing flame retarded wood-plastic composites. Two phosphorous flame retardants were added to an unsaturated polyester resin and compared with a chlorinated unsaturated polyester resin. Wood samples were impregnated in a vacuum and pressure process in an autoclave and cured by means of gamma-radiation.

Ecological flame retardant textiles and compositesEcological flame retardant textiles

Marc Vanhoomissen, Veramitex SA, Belgium, presented the LIFE-FARBioTY project: Fire and Ageing Resistance Biocomposite for Transportation industry (see pinfa Newsletter n°83). This project aims to develop new composite materials based on renewably-sourced flax fibres. Epoxy and polyester resins are being tested with flax fibres and THPC + ammonia treatment for flame retardancy.

Lignin and tannin as flame retardantsLignin and tannin

Fouad Laoutid, Materia Nova, Belgium, presented tests of several bio-based FRs in PLA (poly lactic acid). Lignin grafted ammonium phosphate groups enabled to achieve V0 (3mm) but lignin poses challenges because of high variability between different plant origins and different extraction methods. Phosphorus-grafted tannic acid (1.75%P) in PLA (polylactic acid) reduced peak heat release rate by 1/3, but poses issues because it can decompose the polymer.

Ageing and weather resistanceAgeing and weather resistance

Jean-Luc Gardette, Clermont-Auvergne University, France, discussed the challenges of ensuring that weathering, and in particular ultraviolet radiation (UV), does not deteriorate the properties of flame-retarded polymers. Deterioration is generally related to the polymer itself rather than to additives. Interactions with UV absorbers, anti-oxidants and catalyst-deactivation also need to be verified. PIN effervescent FRs have been shown not to deteriorate polypropylene (PP), nor to interfere with HALS (UV stabilisers). On the other hand, certain nanoclays showed to accelerate PP deterioration, probably because of metal impurities present in the grades tested.

Green chemistry and chemical substitutionGreen chemistry

Jonathan Crozier, pinfa Sector Group manager, Cefic, and Chris Thornton, consultant, explained that PIN flame retardant fire safety solutions are essential to support EU objectives of bio-economy, sustainability (especially sustainable construction materials), circular economy and social inclusion. PIN FRs can be sourced from natural materials, from bio-sourced or from recycled materials. Selection of PIN FRs with optimal health and environmental profiles can limit obstacles to future plastics recycling currently posed by “legacy” halogenated FRs.

Smoke toxicitySmoke toxicity

Anna Stec, UCLAN (University of Central Lancashire), UK, gave her vision of smoke toxicity from fires involving today’s synthetic materials (see summaries of her recent papers in pinfa Newsletters n° 85 and 87). She noted that accidental fires disperse toxicants by three pathways: gaseous molecules, condensing of gas phase pollutants onto soot, and toxicity in residual ash. Smoke toxicity depends on fire development (well ventilated or oxygen deprived conditions), presence of heteroatoms, such as Cl, Br, N, S, Sb in burning materials, and emission of organic toxicants from incomplete combustion. She said that the importance of hydrogen cyanide (HCN) in fire fatalities is often underestimated: HCN is 35x more lethal than carbon monoxide (CO) and rapidly causes unconsciousness. However, HCN is less stable in bodies than CO (so is not identified post-mortem), whereas exposure to CO is measurable after death (as carboxyhaemoglobin).

Innovative flame retardancy applicationsInnovative flame retardancy applications

Alexis Chopin, Eurostar Engineering Plastics, presented radiation-activated cross-linking processes which can improve polymer heat stability and fire performance. In addition to reducing polymer decomposition and improving heat resistance, cross-linking modifies char characteristics. A combination of cross-linking and PIN organo-phoshorous flame retardant in polyamide enabled to achieve UL94-V0 (0.4mm) and EU railway EN 45545 smoke emission R23 HL3. Eurostar now offer PIN-FR radiation crosslinkable polyamide both with and without glass fibre reinforcement.

PIN flame retardants for 3D-printingPIN flame retardants 3D printing

José-Marie Lopez-Cuesta, C2MA Mines d’Alès, France, outlined the importance of developing performance flame retardants for 3D printing. 3D printed objects show high fire risk, because objects are often thin wall but also because tests show that the 3D printed polymer is itself porous (includes air).



France maintains construction fire safety obligationsLe moniteur

The French Parliament is currently processing proposed legislation to enable the Government to simplify by decree certain construction regulation constraints, in order to authorise alternative construction methods or materials intended to achieve the same objectives as the regulatory requirements (“Confidence Law”).

EU LIFE-FLAREX: substituting halogenated textile FRsFlare X

The EU-funded LIFE-FLAREX project aims to replace halogenated flame retardants in home textiles, applying the substitution principle to REACH SVHC (Substances of Very High Concern) and PBT (Persistent, Bioaccumulative, Toxic) chemicals, with the objective of reducing halogenated FR use in this sector by 20% by 2023. An initial report notes that halogenated FRs identifies already as promising alternatives the following PIN FRs: ammonium polyphosphate (APP), poly[phosphonate-co-carbonate], magnesium hydroxide, aluminium hydroxide and aluminium diethylphosphinate (Alpi). The report indicates that there may also be other good alternatives, but that there are data gaps and lack of data for their assessment.