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

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.

Nanomaterials for Multifunctional Textiles

“…This method demonstrated its potential to provide innovative and long-lasting flame resistance treatments on a variety of fabrics, including wool, cotton, polyester, and mixes, with no waste and little effluent. After receiving MLSE treatments, cotton twill furnishing fabrics pad-dried with a proprietary flame retardance gained improved flame resistance with durability [178,179].…”

Chemical cellulose-based fibers of decreased flammability

“…At the same time, the complexes of the ions of metal with the functional groups of complexite are formed [5][6][7]. According to paper [8], the effect of such flame retardant is manifested both in decreasing the number of combustible compounds and in the protection of, for example, cellulose fiber, by the charred layer from burning flames [4] with an increase in coke formation of the polymer.…”

“…One of the modern ways to reduce the flammability of cellulose fibers is to use the new surface technologies based on nanoparticles, sol-gel, and layered depositions [8,9]. Thus, the authors of paper [9] applied a hybrid flame retardant containing the elements of phosphorus, silicon, and nitrogen using the sol-gel method to modify cellulose fibers.…”

Electrocharging face masks with corona discharge treatment

“…Whereas CDT and its close relative plasma treatment are used to treat knitted or woven cloth fabrics to improve dye retention, flame resistance, etc. [24][25][26][27][28][29][30], applying CDT to electrocharge knitted cloth fabrics has not been reported to our knowledge. On the other hand, non-woven polymer electret fabrics are routinely treated with corona discharge to improve their electrocharging characteristics [31,32].…”