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FP5

NEREFITE Report Summary

Project ID: G1RD-CT-2001-00579
Funded under: FP5-GROWTH
Country: France

Co polymerisation of polyamide in order to perform its fire performances

Our work focused on Polyamide through the development of an intrinsically flame retarded Polyamide obtained by a copolymerisation of PA monomers with another monomer that can vectorize a phosphorous moieties.

With such approach, the problems associated with the spinning of fibres containing mineral additives can be overcome (size migration, stability¿) while imparting flame retardant properties to the materials with low Phosphorous content (such as TREVIRA CS fibres for instance).

The critical point here is to find relevant monomers and to fine tune the polymerisation.

We have selected in Rhodia Range a dozen of monomers that were copolymerised with Nylons monomers to synthesise oligoamide (short length PA/P copolymer) that are subsequently extruded with PA. Several problems occurred with almost all the monomers (degradation, no Phosphorous in the obtained oligoamide) but we however identified a phosphonic acid that permitted materials to be obtained. The content in residual phosphonic acid was nevertheless too high to achieve processing (depolymerisation in the extruder). After washing, this content was lowered with a successful extrusion and samples were moulded. FR tests (LOI) on these samples showed that a high increase in LOI is obtained (33.5 vs 28% of O2) with less than 1% of Phosphorous. After optimisation of the process, we were able to obtain a yarn, which is a very positive point.

Our Process expert thinks however that industrialisation of the route followed with the first acid is likely to be extremely difficult since the yield is too low. We then prefer to stall this route with the phosphonic acid and since we have demonstrated the interest of this copolymerisation route (good FR properties with low P content, spinnability achieved) we now search for new monomers in synthesis that may overcome the problem of yield encountered.

Related information

Contact

Jean Emile ZANETTO
Tel.: +33-1-49376800
Fax: +33-1-49376100
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