Influence of N-, P- and Si-based Flame Retardant Mixtures on Flammability, Thermal Behavior and Mechanical Properties of PA6 Composite Fibers

Alisa Sehic, Jelena Vasiljevic, Igor Jordanov, Andrej Demsar, Jozef Medved, Ivan Jerman, Marija Colovic, Fiona Hewitt, T. Richard Hull, Barbara Simoncic

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11 Citations (Scopus)


This research investigated the influence of two flame retardant (FR) mixtures consisting melamine cyanurate (MeCy) and aluminum diethylphosphinate (AlPi), and MeCy and sodium aluminosilicate (SASi) at different weight ratios, on the flammability, thermal behavior and mechanical properties of polyamide 6 (PA6) composite yarns produced by meltspinning. The morphological and chemical properties of PA6/FR filaments were investigated by scanning electron microscopy and Fourier-transform infrared spectroscopy, flame retardancy by vertical burning test UL-94, thermal behavior by thermogravimetric and differential scanning calorimetric analyses, and mechanical properties by tensile tests. The results indicate that within the UL 94 V2 rating, the composite yarns differed significantly from each other in their burning and dripping behavior. The incorporation of both mixtures, MeCy+AlPi and MeCy+SASi, into the PA6/FR yarns significantly decreased the afterflame time relative to pristine PA6, confirming a lower production of flammable volatiles. This phenomenon was attributed mainly to MeCy, which caused an immediate extinguishment of the flame after the withdrawal of the igniting flame. Compared to one component MeCy, the incorporation of the MeCy+SASi mixture enhanced the thermooxidative stability of the PA6/FR yarns because of their additive effect at higher concentrations. In contrast, an antagonistic effect was obtained for the MeCy+AlPi mixture, irrespective of the concentration. Since the incorporation of MeCy+SASi did not drastically reduce the tensile properties of filaments, this mixture enables the production of the PA6/MeCy+SASi composite yarns with the enhanced flame retardancy and thermo-oxidative stability.
Original languageEnglish
Pages (from-to)1194-1206
Number of pages13
JournalFibers and Polymers
Issue number6
Publication statusPublished - Jun 2018

Bibliographical note

This work was supported by the Slovenian Research
Agency, Slovenia (Program P2-0213, Infrastructural Centre
RIC UL-NTF) and the European COST Action FLARETEX
(MP1105) “Sustainable flame retardancy for textiles and
related materials based on nanoparticles substituting
conventional chemicals”. The authors would like to thank
Tomaž Stergar for his help in the melt-spinning process. A.
Š. would like to thank to AquafilSLO d.o.o. for a Ph.D.


  • polyamide 6
  • composite filament yarns
  • flame retardant additive
  • flammability
  • thermo-oxidative stability
  • mechanical properties


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