Chemical and morphological effects of blended sulfonated poly(<scp>styrene‐isobutylene‐styrene</scp>) and isopentylamine for direct methanol fuel cell applications

Journal of Polymer Science

2021

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In this work, novel sulfonated poly(ionic liquid)s block-copolymers based on poly(styrene-isobutylene-styrene) (SIBS) are synthesized for chemical protective clothing (CPC) applications. The synthesis consists of the chloromethylation of SIBS, followed by the incorporation of N-alkylimidazole through chemical grafting, and concluding with sulfonation of the resulting compound. Properties of the membranes are determined as a function of different N-alkylimidazoles (butylimidazole and hexylimidazole) and sulfonation levels (7-23 mol%). Results show that the incorporation of imidazole and sulfonic groups increases the thermal stability of SIBS as well as its water absorption capabilities. The interaction between the ionic moieties in the polymeric matrix allows the formation of hydrophilic nanochannels, which promote the transport of permeants through the membrane. The high water vapor transmission rate (above 2000 g m À2 day À1 ) and values of selectivity (~50) demonstrate that the breathability of the synthesized membrane is improved while blocking the passage of dimethyl methylphosphonate (simulant of agent Sarin). The above mentioned observations suggest that sulfonated SIBS-PIL's membranes are potential materials for CPC applications.

Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

italicIEC ((), \frac{italicmequiv}{g dry polymer}) = \frac{V_{NaOH} \times C_{NaOH}}{W_{italicdry}},

where V NaOH (ml) is the consumed volume of NaOH, C NaOH (mol L −1 ) is the concentration of NaOH, and W dry (g) is the membrane weight in a dry state.

λ = \frac{[H_{2} O]}{[italicionic domain]} = \frac{italicWU \times 10}{18 \times italicIEC},

where WU and IEC are the experimental values of WU (g water g −1 dry polymer) and IEC (mequiv g −1 dry polymer), respectively, and 18 is the molecular weight of water.…”

Section: Resultsmentioning

confidence: 99%

d = \frac{2 π}{q},

where d is the interstitial distance and q is the scattering vector.…”

Section: Resultsmentioning

confidence: 99%

Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 99%

See 3 more Smart Citations

Sulfonated poly(styrene‐isobutylene‐styrene) grafted with hexyl‐ and butyl‐imidazolium chloride ionic liquids

Barrios‐Tarazona

Journal of Polymer Science

2021

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High‐performance blended membranes based on poly(arylene ether sulfone) and sulfonated poly(styrene‐isobutylene‐styrene) for direct methanol fuel cell applications

Ramos‐Rivera

J of Applied Polymer Sci

2021

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In this study, two series of poly(arylene ether sulfone)s (PAES) with hydrophobic blocks made of 4,4 0 -dihydroxyphenyl (BP) and 2,2-bis(4-hydroxyphenyl) propane (BPA) were synthesized. The copolymers were prepared by a coupling reaction between decafluorobiphenyl (DFBP) end-capped nonsulfonated block (PAES A or B) and sulfonated block (SPAES B). The reactive behavior of DFBP facilitates the low-temperature coupling reaction (below 105 C). The final copolymers were blended at distinct weight percent ratios (0, 20, 30, and 40) with poly(styrene-b-isobutylene-b-styrene) (SIBS) at a sulfonation level of 88% to obtain strong and flexible membranes. Morphological, thermal stability, and conduction properties of the resulting membranes were measured and reported here. Results suggest that phase segregation between hydrophobic and hydrophilic domains occurs below 1 meq. g À1 ion exchange capacity. These membranes have low water absorption and high thermal stability. Incorporating SIBS 88 into the blend added elastomeric behavior enhancing transport properties and additional ionic domains, achieving proton conductivities of 0.21 S cm À1 for BPA-based membranes at 50 C (40% SIBS 88). The selectivity of the studied membranes surpasses Nafion ® 117, making them strong candidates for proton exchange membranes in direct methanol fuel cell applications.

Synthesis and characterization of multi‐ionic block copolymers and blended membranes for chemical protective clothing applications

Tarazona

Ramos‐Rivera

J of Applied Polymer Sci

2023

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This study discusses the synthesis of sulfonated amine block copolymers and the effect of multiple ionic domains and counter-ion substitution on polymeric membranes' morphology and transport properties for chemical protective clothing (CPC) applications. The monomers 2-(tert-butylamino) ethyl methacrylate, 2-ethoxy ethyl methacrylate, and styrene were used to prepare the block copolymers by atom transfer radical polymerization (ATRP). The copolymers were then sulfonated by chemical grafting with pendants sulfobutyl groups onto the polymer structure. Properties of the resulting membranes were evaluated as a function of block composition, incorporation of sulfonic groups, and counter-ion substitution. Blended membranes with sulfonated poly(styreneisobutylene-styrene) (SIBS) were also studied. A series of materials characterization techniques (e.g., Fourier-transform infrared spectroscopy [FT-IR], thermogravimetric analysis [TGA], atomic force microscopy [AFM], Smallangle X-ray scattering [SAXS]/wide-angle X-ray scattering [WAXS]) were performed to describe the changes to the membranes. The results indicate that synthesized copolymers lack phase segregation mainly because of a low sulfonation on the central amine block, leading the material to have a low Water/ DMMP selectivity. As the sulfonated copolymers were blended with SIBS 75, the breathability of the membranes were enhanced 1.5 times, and almost all candidates achieved the water vapor transport rate limit of 1500 g m À2 day À1 . Finally, the better-found candidates for DMMP CPC were Mg 2+ membranes, achieving selectivity between 20 and 90 range.