PTFE emulsion treatment of polyimide/superfine glass fiber needle-punched complex filters

In order to improve the filtration properties of the filters, polytetrafluoroethylene (PTFE) emulsion was utilized to modify Polyimide (P84)/superfine glass fiber needle-punched complex filters. The orthogonal test was conducted to optimize treatment process based on quality factor of the filters. Under the optimal treatment conditions, the filtration performances, morphology, pore size, air permeability and tensile properties of complex filters without and with PTFE emulsion treatment were investigated and compared, respectively. The experimental results showed that quality factor was significantly improved compared to the untreated filters, meaning possessing better filtration properties. It benefited from the formation of echelon structure converted deep filtration to surface filtration due to the micro-porous effect. The decreased mean pore size, size distributions and air permeability verified this point. Additionally, tensile strength and elongation improved slightly due to compact entanglements appeared on the filters.