Waste PPS (polyphenylene sulfide) filter textiles were tested as a PIN FR in epoxy, showing reduced PHHR and smoke. PPS fibre bag-filters are widely used for high-temperature industrial gas cleaning, for e.g. combustion plants, metallurgy … Material recycling by re-spinning is difficult and so the resulting waste bags are generally disposed by incineration. In this research, the waste bags were ground to powder (75 – 100 µm) then tested as a PIN FR at 0 – 15 % loading in epoxy. UL 94 V-1 was achieved with 15% loading, with a >40% reduction in peak heat release rate (PHRR), nearly 30% reduction in peak smoke production rate (PSRR) and 45% reduction in peak carbon monoxide production. The FR effect is considered to be related to sulphur content, through char formation and release of non-flammable volatiles which dilute fire gases. The powdered bag material contained some fluorine, because the bags are treated with fluorinated latex for hydrophobicity. pinfa notes that contaminants in the dust removed from offgases during the bags service life should also be considered.
“A new recycling strategy for preparing flame retardants from polyphenylene sulfide waste textiles”, H. Wang et al., Composites Communications 27 (2021) 100852 https://doi.org/10.1016/j.coco.2021.100852