Environmentally Sustainable Flame Retardant Surface Treatments for Textiles: The Potential of a Novel Atmospheric Plasma/UV Laser Technology

Sara Eivazi,A. Horrocks,Baljinder Kandola,Maram Ayesh

doi:10.3390/fib6020031

Abstract

Conventional flame retardant (FR) application processes for textiles involve aqueous processing which is resource-intensive in terms of energy and water usage. Recent research using sol-gel and layer-by-layer chemistries, while claimed to be based on more environmentally sustainable chemistry, still require aqueous media with the continuing problem of water management and drying processes being required. This paper outlines the initial forensic work to characterise commercially produced viscose/flax, cellulosic furnishing fabrics which have had conferred upon them durable flame retardant (FR) treatments using a novel, patented atmospheric plasma/Ultraviolet (UV) excimer laser facility for processing textiles with the formal name Multiplexed Laser Surface Enhancement (MLSE) system. This system (MTIX Ltd., Huddersfield, UK) is claimed to offer the means of directly bonding of flame retardant precursor species to the component fibres introduced either before plasma/UV exposure or into the plasma/UV reaction zone itself; thereby eliminating a number of wet processing cycles. Nine commercial fabrics, pre-impregnated with a semi-durable, proprietary FR finish and subjected to the MLSE process have been analysed for their flame retardant properties before and after a 40 °C 30 min water soak. For one fabric, the pre-impregnated fabric was subjected to a normal heat cure treatment which conferred the same level of durability as the plasma/UV-treated analogue. Thermogravimetric analysis (TGA) and limiting oxygen index (LOI) were used to further characterise their burning behaviour and the effect of the treatment on surface fibre morphologies were assessed. Scanning electron microscopy indicated that negligible changes had occurred to surface topography of the viscose fibres occurred during plasma/UV excimer processing.

Highlights

IntroductionIt is almost 30 years ago that environmental concerns were raised with regard to flame retardants, originally in respect to the potential release of polybrominated dioxins during the incineration of polybrominated diphenyls and diphenyl ethers [1]
The limiting oxygen index (LOI) values of these untreated fabrics (Non-flame retardant (FR)) are listed in Table 2 and not surprisingly are typically in the range 19.8–19.3 vol % observed for 100% cellulosic fabrics
This paper has assessed the ability of a novel Multiplexed Laser Surface Enhancement (MLSE) technology to confer an acceptable level of durability on a range of cellulosic, furnishing-grade fabrics to which a proprietary, non-durable flame retardant has been applied

Summary

Introduction

It is almost 30 years ago that environmental concerns were raised with regard to flame retardants, originally in respect to the potential release of polybrominated dioxins during the incineration of polybrominated diphenyls and diphenyl ethers [1] Since that time these concerns have increased to the extent that in recent years there has been much interest in developing environmentally sustainable, surface flame retardant treatments to textiles as potential replacements for those currently used based on halogen or formaldehyde-based chemistry [2,3]. These concerns have overlapped with the regulatory UK demand that since 1988 all domestic furnishing fabrics shall be resistant to both a lighted cigarette and a simulated match [4]. Given the associated environmental concerns, pressures to move away from such treatments continue to mount

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