Effect of block composition on the morphology and transport properties of sulfonated fluoroblock copolymer blend membranes

Abstract

This study focuses on the relationship between the transport properties and the morphological changes of ionic block copolymer blend membranes, as a function of the fluoroblock chemical composition and loading. Poly(styrene-b-isobutylene-b-styrene) was sulfonated and blended with three different fluoropolymers: Poly(styrene)-bpoly(2,3,4,5,6-pentafluorostyrene)-b-poly (2,2,3,4,4,4-, a difluoroblock copolymer composed of PS-b-PHFBMA and a homopolymer composed of PHFBMA. Equilibrium and transport properties (e.g., ion exchange capacity, water uptake, water content, proton conductivity, and methanol permeability), were shown to be significantly influenced by the chemical nature of the fluoroblock copolymer, the fluoropolymer content, and their resulting morphology. Proton conductivity and methanol permeability were very sensitive to the incorporation of PHFBMA. Polymer blends composed of sulfonated poly(styrene-b-isobutylene-b-styrene) (SIBS SO 3 H) and PHFBMA above 9 wt% showed interconnected ionic domains that have a shorter correlation length and high water content, which results in improved transport properties for direct methanol fuel cell (DMFC) applications. POLYM. ENG. SCI., 57:1262-1272, 2017. EXPERIMENTAL MaterialsZonyl V R BA-L fluorotelomer intermediate (70 wt% and M n $443 g/mole) was acquired from Sigma-Aldrich. SIBS was purchased from Kaneka V R (30 wt% polystyrene and M n $65,000 g/mole). PS-b-PHFBMA was synthesized following the procedure of a previous study [20] (9 wt% Zonyl V R , 55.52 wt% PS, 35.5 wt% PHFBMA, and M n $ 11,800 g/mole). Chemicals used for the sulfonation of SIBS and the membrane casting included: sulfuric acid (Sigma Aldrich, 95-98%), acetic anhydride (Aldrich Chemical, 991 %), hexyl alcohol (Acros Organics, 98%, extra pure), methanol (Fisher Scientific, 99.9%), SCHEME 1. Polymerization reaction for PS-b-PFS-b-PHFBMA.

Efecto de las membranas con Cu+2 sobre el proceso de filtración y capacidad de biocida contra Escherichia coli

“…Un estudio utilizando SAXS podría confirmar el cambio del tamaño del poro inducido por la incorporación del cobre en las membranas. Estudios han utilizado esta técnica para determinar este parámetro en las membranas (Guerrero- Gutiérrez et al, 2017;Syed et al, 2018).…”

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

“…These types of membranes improve their proton conductivity and reduce methanol permeability (Huang et al, 2019;Jung et al, 2004). Sulfonated thermoplastic elastomers blended with well-ordered fluoroblock copolymers were studied to modify its morphology, Ion-Exchange Capacity, and water uptake (Guerrero-Gutiérrez et al, 2017). These advanced well-ordered fluoropolymers with specific structures and lower polydispersity were synthesized using Controlled radical polymerization (CRP) (Guerrero-Gutiérrez et al, 2017;Matyjaszewski, 2012).…”