Arkema: Developing Intrinsically Fire-Retardant Bio-Based Polymers

Arkema: Developing Intrinsically Fire-Retardant Bio-Based Polymers


Within the THERMOFIRE project, Arkema is pursuing a high-risk, low-TRL approach to revolutionize fire-retardant polyamide 11 (PA11). Unlike traditional methods that mix PA11 with flame-retardant additives, Arkema is inventing a new reactive route to synthesize intrinsically fire-retarded PA11 by incorporating phosphorus-based monomers directly into the polymer backbone.

Innovative Approach:

The strategy focuses on developing phosphorus-containing diacid monomers through a two-step chemical reaction. The DOPO molecule (9,10-dihydro-9-oxa-10 phosphaphenanthrene-10-oxide) was selected for its well-documented reactivity, particularly its P-H bond, which reacts efficiently with double bonds through Kabachnik and Pudovik reactions.

Highlights of Recent Progress:


1. Synthesis of P-Containing Diacids :

  • High-yield synthesis (>95%) of phosphorus-containing
    monomers was achieved.
  • Characterization was conducted using NMR, TGA, and
    DSC techniques

2. Polymerization Challenges:

  • Monomers were polymerized with bio-based aliphatic DA10 and amino undecanoic acid (Amino 11) using
    molten-state polycondensation.
  • However, SEC analysis revealed low molecular weights and high polydispersity, indicating extensive branching and partial solubility.
  • These issues stem from unexpected side reactions caused by grafted DOPO moieties, which are currently under investigation using model molecule approaches.

3. Initial Performance Testing:

  • The synthesized bio-based PA11, containing 1 wt%
    phosphorus, was processed and tested under the UL94
    standard, achieving a V2 ranking due to flaming drips.

Next Steps:


To address the challenges observed, Arkema plans to replace DOPO with two alternative phosphorus-containing building blocks that theoretically reduce side reactions. This transition is expected to yield better polymerization control and improved fire-retardant properties. Arkema’s innovative efforts are paving the way for bio-based, intrinsically fire-retardant materials, a critical advancement for the sustainability goals of the THERMOFIRE project.

 

Publication date: 02/11/2025

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