Linear Viscoelasticity and Cation Conduction in Polyurethane Sulfonate Ionomers with Ions in the Soft Segment–Single Phase Systems

Abstract

PEO-based polyurethane sulfonate ionomers with various PEO chain lengths and sodium counterions were synthesized and characterized by both linear viscoelasticity (LVE) and dielectric relaxation spectroscopy (DRS). Since p-phenylene diisocyanate is a small hard segment, the ionomers were found to be single phase with only one DSC T g which increases with both ion content and hard segment content. An electrode polarization model was used to simultaneously determine the temperature dependence of conducting ion concentration and their mobility, which show Arrhenius and Vogel–Fulcher–Tammann (VFT) temperature dependences, respectively. The polymer dipole relaxation probed by DRS was found to be between 103 and 106 times faster than the mechanical segmental relaxation observed in LVE data near T g, suggesting that most polymer modes need to wait for the ions to rearrange. The dielectric relaxation, mechanical relaxation, and ionic conductivity all show good correlation with DSC T g and are related to ion rearrangement. Lower ion content creates lower T g, lower activation energy for conducting ions, and higher ion mobility, as sodium cations interact strongly with both PEO and the urethane linkage.

Structures, properties and applications of the polyurethane ionomers

“…This phase is related to high Young's modulus (10 MPa) [33]. The large amount of polyurethane coatings based on the PUI described above exhibits features typical for elastomers [3,6,14,26,28,32,52,61]. The effect of ionic group content on thermal, structural and shape memory properties of segmented polyurethane ionomers based on PCL, MDI, BD and DMPA neutralized with TEA was analyzed in detail in Ref.…”

“…In this chapter, attention has been paid to the less widespread applications of the PUIs described above. The chemical structure, diversity of hydrogen interactions and strong electrostatic interactions as well as the resulting phase-related fixation observed in polyurethane ionomers have created new possibilities of using these polymers as special materials in electronics and catalysis [3,34,38]. It was proved that the presence of charges trapped in functional groups can be used to produce polymers with increased electrical conductivity.…”

“…Since then, there have been many interesting reports developing this topic in the scientific reports and patents [2]. This is related to the progress in the production of new types of polyurethanes with a controlled structure in which polar ionic groups affecting the phase structure of PU elastomers and determining their dielectric and mechanical relaxations, ionic conductivity and hydrophilicity are key factors [3]. Those groups allow forming dispersions and emulsions in water, which was previously considered as unfavorable and even hostile to the classical methods of polyurethane synthesis.…”

A New Strategy to Synthesize α,ω‐Dihydroxy Multiblock Copolymers via [CpRu(CH3CN)3]PF6/Quinaldic Acid Catalyst

“…Therefore, having a special terminal groups of MBCs which can be used as thermosetting material were not yet received much attention and research. As is well known, the preparation of α,ω‐dihydroxy polymers has been a hot subject of investigation for several decades owing to their diverse applications in the fields of adhesives and biomedical and elastomeric materials . However, so far, the syntheses of α,ω‐dihydroxy block copolymers were mainly on di‐ and triblock copolymers via living polymerization .…”

“…As is well known, the preparation of α,ωdihydroxy polymers has been a hot subject of investigation for several decades owing to their diverse applications in the fields of adhesives and biomedical and elastomeric materials. [23][24][25][26][27][28] However, so far, the syntheses of α,ω-dihydroxy block copolymers were mainly on di-and triblock copolymers via living polymerization. [29][30][31][32][33][34] Although according to basic knowledge, α,ω-dihydroxy MBCs could be synthesized by adding different monomers with living polymerization, sequentially, in reality, Scheme S1, Supporting Information.…”