ED Sciences Chimiques
Study of phosphorus-based flame retardants for the fireproofing of bio-based polyamides: Application to PA-11
by Clément DESGOULIERES (Laboratoire de Chimie des Polymères Organiques)
The defense will take place at 9h30 - Amphithéâtre 1 ENSMAC, Bât A 16 Avenue Pey Berland 33607 Pessac CEDEX
in front of the jury composed of
- Henri CRAMAIL - Professeur des universités - Université de Bordeaux - Directeur de these
- Julien BERNARD - Chargé de recherche - Laboratoire Ingénierie des Matériaux Polymères - Rapporteur
- Sophie DUQUESNE - Professeure - Centrale Lille Institut – ENSCL - Rapporteur
- Sylvain CAILLOL - Directeur de recherche - Institut Charles Gerhardt Montpellier (ICGM) - Examinateur
- Rodolphe SONNIER - Maître de conférences - Laboratoires Polymères Composites hybrides (PCH) - IMT Mines Alès - Examinateur
- Jean-Jacques FLAT - Docteur - Arkema - Examinateur
- Stéphane GRELIER - Professeur des universités - Université de Bordeaux - CoDirecteur de these
This PhD work focuses on the synthesis of fireproofed polyamide-11 (PA-11) with phosphorus-based flame retardants (FR). First, a reactive fireproofing of PA-11 has been studied. According to a first approach where the phosphorus atom is in an extra-catenary position, DOPO and DPPO-based diacid comonomers have been synthesized and then copolymerised with 11-Aminoundecanoic acid (A11) between 200 and 250°C. Copolyamides revealed partially soluble in HFIP, with a partial loss of the phosphorus species during the polymerisation and were unclassified or V-2 rank (2 mm) for UL94 test with 2 wt% of phosphorus (P). In order to improve the thermal stability of the phosphorous monomer, the diacid monomer, BCPPO, has been studied as a third reactive FR system, for an intra-catenary fireproofing approach. The copolymerisation of BCPPO with A11 gave fully soluble polyamides in HFIP, with a thermal stability similar to PA-11. However, a degradation of the thermomechanical properties of PA-11 is observed, and only a V-2 rank (2 mm) is obtained for UL94 test (with 2 wt% P). At the same time, the additive fireproofing of PA-11 has been investigated, with the incorporation of new phosphorus additives by extrusion, the latter being synthesised by Abramov or Pudovik reactions. Remarkably, some of these systems showed a V-0 rank (2 mm) for UL94 test with 1 and 2 wt% of phosphorus, without decreasing the mechanical properties of PA-11. Lastly, a comparison between additive and reactive fireproofing routes on identical systems, showed that the additive way was the most efficient one to fireproof PA-11, with only a slight disturbance of its mechanical properties.