Fibres flame retardance

Comments Stat-Kon grades contain carbon fibres Lubricomp has PTFE. FR = CF = carbon fibres. flame retardant, GF = glass fibres. ... 

A large number of grades is available, one supplier alone offering about 40, including unreinforced, glass- and carbon-fibre reinforced, mineral filler reinforced, impact modified, elastomer modified, flame retardant and various combinations of the foregoing. 

CE is also potentially a useful alternative analytical tool for monitoring of chemicals (dyes, flame retardants and lubricants) involved in various steps of the textile fibre manufacturing process. In this area, CE compares favourably with existing techniques. CZE-MSn was used for the analysis of sulfonated azo dyes [942]. A variety of fluorescent analytes including thiazole orange dyes have been characterised by CE-FLNS [943]. 

It is possible to determine components in complex EPs where matrix effects can be severe. For example, zinc (as zinc borate), chlorine (as dechlorane flame retardant), antimony (as oxide) and fibre-glass have been determined in nylon using just one standard. Many users have refined the universal precalibrated programmes for standardless XRF and made them more efficient for matrix correction by using variable correction coefficients. OilQuant offers possibilities for analysing polymers [243]. Software packages usually provide ... 

Sodium hydroxide is the alkali usually used in conjunction with dithionite. Sodium carbonate is a possible alternative when Cl Solubilised Sulphur dyes are used but is insufficiently alkaline for the Cl Sulphur brands, requiring careful control if over-reduction and the associated lower yields are to be avoided [30]. Typical concentrations are given in Table 12.24. The system of sodium carbonate and sodium dithionite used to reduce blue and black Cl Solubilised Sulphur dyes is particularly suitable for flame-retardant viscose fibres that are sensitive to strong alkalis, since it preserves a satisfactory level of flame retardancy [30]. It is also possible to use a mixture of dithionite with sodium sulphide in alkaline media. 

For plastics, ISO 3451 Plastics — Determination of Ash describes various methods for determination of the ash content of different types of plastics including those containing glass fibres and/or flame-retardants. 

Vinyl bromide may form in air as a degradation product of 1,2-dibromoethane. It may also be released to the environment from facilities which manufacture or use vinyl bromide as a flame retardant for acrylic fibres. Vinyl bromide has been qualitatively identified in ambient air samples (United States National Library of Medicine, 1998a)... 

Dimethyl hydrogen phosphite is used as a flame retardant on nylon 6 fibres, as a chemical intermediate in the production of pesticides and in lubricant additives and adhesives. No data on occupational exposure levels were available. A potential source of exposure to this chemical is from its occurrence as a degradation product of the chemical intermediate trimethyl phosphite and of pesticides such as trichlorphon and malathion (lARC, 1990). 

Kaur, I., Sharma, V., and Sharma, R., Development of flame retardant cotton fabric through grafting and post-grafting reactions, Indian J. Fibre Textile Res., 2007, 32, 312-318. 

Braun, U., Schartel, B., Fichera, M.A., and Jaeger, C. 2007. Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6. Polym. Deg. Stab. 92 1528-1545. 

Horrocks A.R. and Davies, P.J. 2000. Char formation in flame-retarded wool fibres. Part 1. Effect of intumescent on thermogravimetric behaviour. Fire Mater. 24 151-157. 

Zhang, S. and Horrocks, A.R. 2003. A review of flame retardant polypropylene fibres. Prog. Polym. Sci. 28 1517-1538. 

Anna, P., Zimonyi, E., Marton, A., Szep, A., Matko, Sz., Keszei, S., Bertalan, Gy., and Marosi, Gy. 2003. Surface treated cellulose fibres in flame retarded PP composites. Macromolecular Symposia 202 245-254. 

Kandola, B. K., Horrocks, A. R., and Rashid, M. R. Effect of reinforcing element on burning behaviour of fibre—Reinforced epoxy composites, Proceedings of 17th Annual BCC Conference on Flame Retardancy, Stamford, CT, May 22-24, 2006. 

Kandola, B.K. and Horrocks, A.R. 2000. Complex char formation in flame-retarded fibre intumescent combinations—IV. Mass loss calorimetric and thermal barrier properties. Fire Mater., 24 265-275. 

Nametz RC, "Flame Retarding Synthetic Textile Fibres", Ind Eng Chem 62 (1970) 41-53. 

One important thermal degradation mechanism of cellulose fibres (cotton, rayon, linen, etc.) is the formation of the small depolymerisation product levoglucosan (Fig. 8.7). Levoglucosan and its volatile pyrolysis products are extremely flammable materials and are the main contributors to cellulose combustion. Compounds that are able to hinder levoglucosan formation are expected to function as flame retardants for cellulose. The crosslinking and the single type of esterification of... 

Chemicals that can yield phosphoric acid during the early stages of fibre pyrolysis form the majority of successful flame retardants for cellulose. However, it is not sufficient to supply just phosphoric acid precursors. The presence of nitrogen has been found to provide a synergistic effect with phosphorous. Minimum levels of added phosphorous and nitrogen for effective flame retardancy have been estimated at 2 % P and 1 % N. However, these minimum levels can vary greatly depending on fabric construction and test requirements. 

Although inorganic salts can provide excellent flame-retardant properties for cellulose, reasonable laundering durability must be incorporated into any finish destined for apparel use. The most successful durable flame retardants for cellulose are based on phosphorous- and nitrogen-containing chemical systems that can react with the fibre or form crosslinked structures on the fibre. The key ingredient of one of these finishes is tetrakis(hydroxymethyl)phosphonium chloride (THPC), made from phosphine, formaldehyde and hydrochloric acid (Fig. 8.11). THPC reacts with urea to form an insoluble structure on cellulose in a pad-dry-cure process (Fig. 8.12). 

A variation on the THPC-urea system was developed to produce finishes with less stiffness and fibre damage (Proban process). A precondensate is prepared by the careful reaction of THPC with urea. This precondensate is padded onto the fabric and the fabric is dried to a specific moisture content ( 15 %). The fabric is then exposed to ammonia vapours in a special reaction chamber, followed by oxidation with hydrogen peroxide (Fig. 8.13). The polymer that forms is primarily located in the lumen of the cotton fibre. The final finish provides durable flame retardancy to cotton with much improved fabric properties. It is important to note... 

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