Improving the comprehensive performances of phosphonic acid functionalized poly(ether sulfone) by compositing with 1H-1,2,3-triazol-4-yl functionalized poly(ether sulfone)

Abstract

The comprehensive performances of phosphonic acid functionalized poly(ether sulfone) (PES-PA) are improved by compositing with 1H-1,2,3-triazol-4-yl functionalized poly(ether sulfone) (PES-Tri). The PES-PA and PES-Tri are synthesized via the nucleophilic aromatic substitution (SNAR) polycondensation, respectively, of diethyl 2,5-dihydroxyphenylphosphonate and 4,4′-difuorodiphenylsulfone and of bisphenol A and 3,3′-diethynyl-4,4′-difluorodiphenylsulfone, and followed by hydrolysis or post-polymerization click reaction and deprotection reaction. In addition, two functionalized monomers, diethyl 2,5-dihydroxyphenylphosphonate and 3,3′-diethynyl-4,4′-difluorodiphenylsulfone are synthesized. Best comprehensive performances are achieved in the composite membrane consisting of 80% PES-PA and 20% PES-Tri by molar ratio of the functional structure units. At 100 °C and 90% RH (relative humidity), the proton conductivity of the composite membrane is 12.8 mS cm−1, about 1.8 times improvement compared with pristine PES-PA. In addition, the hydrophilicity and methanol permeability are alleviated, the water uptake is reduced from 31.3% to 16.1% at 100 °C and 90% RH and methanol permeability is reduced from 19.0 × 10−8 cm2 s−1 to 0.79 × 10−8 cm2 s−1 at 30 °C.