Gridded Fibers’ Restricted Melting Strategy for Gas Permeance and Binding Enhancement of the ePTFE/PPS Filter

In this work, a high-gas-permeance expanded polytetrafluoroethylene/gridded fibers/polyphenylene sulfide (ePTFE/GF/PPS) filter was developed by embedding the gridded fibers as the interlayer to restrict the melting diffusion behavior of poly(phenylene sulfide) (PPS). The influence of gridded fibers with different melting temperatures on the air permeance, composite fastness, and heat tolerance was investigated. The results show that copolyamide (PA) gridded fiber with low melting temperature can weaken the effect of PPS melting so as to increase the air permeance of the ePTFE/PPS filter by 32%, which is suitable for low-temperature environments below 160 °C. The ePTFE/PAN/PPS membrane had an 8% increase in air permeance while maintaining the overall performance stable, with a heat tolerance of 200 °C. Poly(vinyl alcohol) (PVA) with a melting temperature close to that of PPS as the interlayer exhibited enhanced fastness as a compensation for the lower air permeance because of co-melting. All of the filters showed filtration efficiencies of above 99.99% and filtration resistances below 210 Pa in the particulate matter (PM) filtration experiment. The successful introduction of the gridded fiber as the intermediate layer provides a new perspective to design a composite filter with high gas permeance.