This work discusses the effect of isopropyl phosphate (IP) on the transport properties of sulfonated poly(styrene‐isobutylene‐styrene) (SO3H SIBS) as membranes for direct methanol fuel cell (DMFC) and chemical and biological protective clothing (CBPC) applications. The properties were determined as a function of SIBS sulfonation level (i.e., 24, 34, 49, and 84 mol %) and IP loading (i.e., 1, 3, 5, 11, and 15 wt %). A comprehensive material characterization study (e.g.
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. PO3H2SWCNTs increased the proton conductivity but at a high sulfonation level (i.e.
- PAR ID:
- 10078168
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Polymer Science Part A: Polymer Chemistry
- Volume:
- 56
- Issue:
- 21
- ISSN:
- 0887-624X
- Page Range / eLocation ID:
- p. 2475-2495
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract , FTIR, TGA, AFM, and SAXS) was performed to confirm the presence of the phosphate groups in the polymer matrix, assess the thermal stability of the proton‐exchange membranes (PEMs), and understand how the unique interactions between the phosphate and sulfonic groups influenced the nanostructure of SO3H SIBS. The transport properties, water absorption capabilities (i.e., swelling ratio, water uptake, etc.), oxidative stability, and ion‐exchange capacity (IEC) were performed to evaluate the impact of IP on the properties of the resulting solvent‐casted membranes. Results suggest that the morphology, thermal stability, and vapor permeability are governed by the sulfonation level, whereas the IEC, oxidative stability, water absorption capabilities, and the rest of the transport properties are dominated by the ionic content (i.e., sulfonic and phosphate groups) and their synergistic effects. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019 ,136 , 47009. -
Graphene oxide (GO) and its sulfonated analog (sGO) have been incorporated into sulfonated poly(styrene‐isobutylene‐styrene) (SO3H SIBS) in order to enhance its water retention and proton conductivity, while aiming to block permeant passage through the material. The polymer nanocomposite membranes (PNMs) were tested for two applications: direct methanol fuel cell and chemical and biological protective clothing. The transport properties of the membranes were determined as a function of SIBS sulfonation level (i.e., 37, 61, and 88 mol%), filler type (i.e., GO and sGO) and filler loading (i.e., 1, 3, 5, and 10 wt%). Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the functionalization and incorporation of the fillers into SO3H SIBS. No significant changes were observed in the thermal stability or FTIR spectra of the PNMs after addition of the fillers. Dissimilar behaviors were observed for the ion exchange capacity, water absorption capabilities and transport properties of the membranes after incorporation of the fillers. Atomic force microscopy (AFM) phase images and Fenton's test results indicate that the oxidative stability of the PNMs is associated to the interconnectivity between the hydrophilic domains of the fillers and SO3H SIBS. The PNMs presented low permeability and high proton conductivity and thus, functioned adequately for both applications. POLYM. ENG. SCI., 59:E455–E467, 2019. © 2018 Society of Plastics Engineers
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