Modification of polyacrylonitrile fibre to reduce combustibility

Abstract

677.17.494Flame-resistant PAN fibre was obtained by impregnating the finished fibre with solutions of flame retardants (FR) in different ratios of components. The oxygen index of the modified samples increased to 34.5 vol. %. The presence of a reaction between the PAN fibre and the FR due to both chemical and van der Waals and hydrogen bonds was established by calculating the effectiveness factor of the sorption reaction. The effect of FR on pyrolysis of the modified fibres was investigated. Cyclization processes began in the modified fibre at lower temperatures than for the initial PAN fibre, took place at a lower rate, and were accompanied by a high yield of coke residue.The combustibility is one of the criteria that determine the possibility of using polymers in many branches of industry. Reducing their fire hazard is one of the most important scientific and practical problems. This is confirmed by the law "On Fire Safety" passed in the Russian Federation. Problems of reducing the combustibility of textile materials remain the center of attention in research. This is indicated by the projected increase in production of fireproof textile materials.Great attention is focused on surface treatment of fabrics and fibres with flame retardants (FR) or flame retardant systems (FRS) in modern methods of reducing the combustibility of polyacrylonitrile (PAN) fibre.Note that few FR are effective in reducing the combustibility of PAN fibres, so that modification of PAN fibres using synergistic systems consisting of Pyrofix (PF) and diamidomethylphosphate (T-2) were examined here. Urea (UR) and polysaccharides (PS) were used to fix the FR in the structure of the fibre and preserve the fireproofing effect.Modification, conducted in previously selected conditions [1], included the following stages: impregnation of the finished fibre with solutions of FR with a different ratio of components at 20°C for 60 sec and bath ratio of 5; drying to a constant weight at 25±5°C; heat treatment at 150°C for 10 min for the FR to react with the fibre; washing at 40°C to remove unreacted preparation; drying.Calculation of the effectiveness factor of the sorption reaction of the fibre with the FR, which characterizes retention of the FR in the fibre after laundering, showed that the greatest increase in the effectiveness of the sorption reaction was attained by incorporation of UR, which can form inclusion compounds with both organic and inorganic substances in the modifying bath (Table 1).Since PAN fibre passes into the devitrified state at high temperatures, the effect of these conditions on the effectiveness of the reaction of the FR with the fibre was determined in the studies.In modification with the FR and FRS investigated, the high efficacy of treatment of the fibre with a bath containing mixed FR, (T-2 + PF) + PS, was established (Fig. 1). This effect persisted with all methods of modification. Moreover, it should be noted that preliminary heat treatment of unmodified PAN fibre at 100°C and impregnation with the bath at 85°C insigni...

Processing, Structure, and Properties of PAN/MWNT Composite Fibers

“…[2,16,41] Apart from being the most predominant precursor candidate for commercial carbon fiber, PAN fibers are also used in applications like mattress upholstery, fire-fighter clothing, and aircraft textiles due to its high thermal stability, high char yield, and appropriate mechanical properties. [42][43][44][45][46][47] In this study, high concentration CNT/PAN composites were studied where fibers containing 5, 10, 15, and 20 wt.-% MWNT loadings were fabricated. The fibers were characterized for their mechanical, dynamic mechanical, thermomechanical, and electrical properties.…”

Surface and Bulk Modification of Synthetic Textiles to Improve Dyeability

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