Flame Retardant Polyamide Fibres: The Challenge of Minimising Flame Retardant Additive Contents with Added Nanoclays

Abstract

This work shows that halogen-free, flame retarded polyamide 6 (PA6), fabrics may be produced in which component fibres still have acceptable tensile properties and low levels (preferably ď10 wt %) of additives by incorporating a nanoclay along with two types of flame retardant formulations. The latter include (i) aluminium diethyl phosphinate (AlPi) at 10 wt %, known to work principally in the vapour phase and (ii) ammonium sulphamate (AS)/dipentaerythritol (DP) system present at 2.5 and 1 wt % respectively, believed to be condense phase active. The nanoclay chosen is an organically modified montmorillonite clay, Cloisite 25A. The effect of each additive system is analysed in terms of its ability to maximise both filament tensile properties relative to 100% PA6 and flame retardant behaviour of knitted fabrics in a vertical orientation. None of the AlPi-containing formulations achieved self-extinguishability, although the presence of nanoclay promoted lower burning and melt dripping rates. The AS/DP-containing formulations with total flame retardant levels of 5.5 wt % or less showed far superior properties and with nanoclay, showed fabric extinction times ď 39 s and reduced melt dripping. The tensile and flammability results, supported by thermogravimetric analysis, have been interpreted in terms of the mechanism of action of each flame retardant/nanoclay type.

Preparation and characterization of polyamide 6 fibre based on a phosphorus-containing flame retardant

“…On the other hand, ame retardants are usually introduced to PA6 via melt processing and the ame retardant in the composites is easily exuded by the water due to the larger exposure area of bre materials which causing the deterioration of ame retardancy. 10,11 Thus, the ame retardant with high efficiency and persistence is needed for PA6 bres. Several phosphorus-containing reactive ame retardants have been used to prepare ame retardant polyamide because of their high ame retardant efficiency as well as no release of toxic gases during combustion.…”

The flame retardancy and smoke suppression effect of a hybrid containing dihydrogen phosphate anion modified reduced graphene oxide/layered double hydroxide on epoxy resin

“…Among these ame retardants nanoscale llers, such as graphene, LDH, MoS 2 , carbon nanotubes, and clay, have received wide attention. [6][7][8][9][10] Graphene has been a focal area of research due to its large specic surface area and excellent mechanical, electrical and thermal properties. 11,12 According to a number of studies, the ame retardancy of polymers can be increased by adding graphene, and this is mainly attributed to the graphene layer's role of a physical barrier in the combustion process of polymers, which effectively slows the volatilization of ammable gases, protects the matrix, and prevents further combustion.…”

Recent Advances in Production of Flame Retardant Polyamide 6 Filament Yarns

“…Th ese results confi rm the existence of FR synergism between MPP and halloysite nanotubes in PA6. Horrocks et al [16] produced PA6/FR composite multifi lament yarns by using 2 wt% organically modifi ed montmorillonite nanoclay (NC), Cloisite 25A (Southern Clay Products Inc., USA), together with two types of FR formulations: the vapour phase active micro-sized particles of AlPi, Exolit OP935 (Clariant, Switzerland), at 10 wt%; and the condensed-phase intumescent active mixture of AS (Sigma-Aldrich, UK) and dipentaerythritol (DP) (Fisher Scientifi c, UK) at 2.5 wt% and 1 wt%, respectively. All the yarns had acceptable tensile properties and were knitted into knit fabrics.…”