Influence of carboxylated and phosphonated single‐walled carbon nanotubes on the transport properties of sulfonated poly(styrene‐isobutylene‐styrene) membranes

Abstract

This study discusses the effect of carboxylated (COOH) and phosphonated (PO3H2) single‐walled carbon nanotubes (SWCNTs) on the transport properties of sulfonated poly(styrene‐isobutylene‐styrene) (SO3H SIBS) as polymer nanocomposite membranes (PNMs) for direct methanol fuel cell (DMFC) and chemical and biological protective clothing (CBPC) applications. The properties were determined as a function of sulfonation level of SIBS, SWCNTs functionalization and loading. A comprehensive materials characterization study was performed to understand the interactions between the nanofillers and the functionalized polymer matrix, and to determine the effect of their incorporation on the resulting nanostructure of the PNMs. Results indicate that the sulfonation level is the variable that dictates nanofiller dispersion, mechanical properties, water absorption capabilities, morphology, and oxidative stability of SO3H SIBS. Meanwhile, the nanofiller loading and functionalization influenced the transport properties. The nanofillers reduced methanol permeation. PO3H2 SWCNTs increased the proton conductivity but at a high sulfonation level (i.e., 90 mol %), the ionic interconnectivity caused a more complex morphology decreasing the transport of protons. Optimal selectivity in transport properties were found with a sulfonation level of 61 mol % and a PO3H2 SWCNTs loading of 1.0 wt. % for DMFC and 0.5 wt. % for CBPC due to changes in morphology and the unique transport mechanism of permeants through the PNMs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2475–2495

Effect of Sulfonated Block Copolymer on the Equilibrium and Thermal Properties of Sulfonated Fluoroblock Copolymer Blend Membranes

“…The capacity of the membrane to absorbed water is also related to the IEC (Ruiz-Colón et al, 2018). SIBS SO 3 H exhibits a water swelling of 608%.…”

Rational Design of a Zr-MOF@Curli-Polyelectrolyte Hybrid Membrane toward Efficient Chemical Protection, Moisture Permeation, and Catalytic Detoxification

“…For the sake of comfort to the users in practical applications, moisture breathability should be taken into consideration to relieve physical fatigue and avoid heat stress. Benefiting from the appreciable chemical resistance and moisture permeability, polyelectrolyte membranes have been recognized as promising protective materials, including perfluorosulfonic ionomers, − polystyrene sulfonic acid (PSSA), , sulfonated poly­(styrene–isobutylene–styrene) triblock copolymer (SIBS), − and poly­(vinylidene fluoride)-grafted sodium polystyrene sulfonate (PVDF-g-SSS) . Their distinctive microscaled structures resulting from the hydrophilic–hydrophobic phase separation can facilitate the permeation of water molecules and reject the permeation of organic chemicals simultaneously.…”

Preparation and Chemical Protective Clothing Application of PVDF Based Sodium Sulfonate Membrane

“…The self-assembly of a PEM upon solvation can form a permselective network containing nanoscale hydrophilic channels. Typical examples of such selective permeable membranes are sulfonated poly(styrene-isobutylene-styrene) (SIBS), triblock copolymer, perfluorinated ionomers, and polystyrene sulfonic acid (PSSA) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. However, sulfonated SIBS has poor selectivity between 0.7 and 35 [ 19 ], Nafion is too expensive for chemical protective clothing usage ($1600 m −2 for Nafion 117) [ 20 ], and polystyrene sulfonic acid has a poor mechanical performance [ 14 ].…”