The fire retardant properties and pyrolysis mechanism of polysulfonamide (PSA) fibers

Abstract

In the present work, the fire retardant properties and pyrolysis mechanism of polysulfonamide (PSA) fibers were investigated by cone calorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and pyrolysis-gas chromatography-mass spectrometry. The fire retardant behaviors were reflected by the cone calorimeter data under heat fluxes of 35, 50, and 75 kW/m 2 . This demonstrated that, when exposed to higher heat flux, PSA fibers were ignited easier and burned more completely, indicated by lower time to ignition and higher peak heat release rate. It was further confirmed from the morphology of the residual chars that the original fiber shape can be kept at lower heat flux, but it changed into coherent carbonaceous chars with holes at higher heat flux. In comparison of the FTIR spectra of raw fibers with residual chars, it was noticed that upon heating, the amide linkage was more liable to be broken than that of sulfone groups. Additionally, with elevated heat flux, most of the absorption bands vanished and transformed into the typical feature of carbonaceous material. The pyrolysis products showed that some volatile products with small molecular weight, such as benzene, benzonitrile, and aniline, can be created at high temperature, which can be easily ignited. With this research, the fire retardant properties of PSA fibers are revealed and the corresponding pyrolysis mechanism is proposed, which can guide its application in practice.Polysulfonamide (PSA) fibers, with superior temperature resistance, high limiting oxygen index (LOI, up to 33%), and excellent chemical properties, were first developed by Shanghai Tanlon Fiber Co, Ltd (China) with the trademark Tanlon Õ . They belong to the fiber series of aromatic polyamides with conjugated aromatic rings and sulfonyl groups in the main backbone, which endow them with outstanding thermal stability and excellent chemical properties. 1 These unique features enable them to be applied in various fields, such as flame retardant protective clothing, high temperature filtration materials, thermal insulation materials, battery membrane, and so on. [2][3][4][5][6] With excellent fire retardant properties, PSA has attracted much attention in both industrial and academic circles, including further performance improvement, extension of practical applications, thermal stability, etc. To further improve the performance of PSA fibers, a lot of researchers have made great efforts to investigate the effect of the spinning process on its structure and resultant performance. 7,8 Yu et al. employed heat stretching at temperatures

Performance of poly sulfonamide/nano-silica composite for adsorption of thorium ions from sulfate solution

“…Polysulfonamide was prepared [36][37][38][39] by dissolving of 0.1 M/L of 4, 4′ diamino diphenyl sulfone (APS) in 120 mL of N, N dimethylacetamide (DMAc) and kept stirring the mixture in the three-necked flask, till the solution (APS/DMAc) was dissolved. The system was cooled to − 17 °C using a bath of a mixture of acetone and liquid nitrogen.…”

Preparation and Characterization of Electrospun PAN/PSA Carbonized Nanofibers: Experiment and Simulation Study

“…Polysulfone amide (PSA) is a representative polymer for new-type high-temperature resistant fibers, and the micron-sized PSA fibers have been widely used [ 26 , 27 , 28 , 29 ]. Polyacrylonitrile (PAN) is a conventional chemical fiber and is an important material for the preparation of carbon fiber precursors [ 30 , 31 , 32 ].…”

Estimation of the radiant performance of flame-retardant fabrics considering thermal degradation effect

“…This may be explained by that char layer produced by the thermal degradation of PSA fabrics was relatively strong, which delayed the heat transfer toward backside of the fabric. 18 Obviously, the pyrolysis of PSA and Nomex IIIA fabrics exerted an important impact on its thermal properties under intense heat flux condition. But in a low radiant heat flux exposure, the effect of thermal degradation on RPP became inconspicuous.…”