Properties of solid solutions of poly(ethylene oxide)/epoxidized natural rubber blends and LiClO₄

Abstract

Solid solutions of blends of poly(ethylene oxide) (PEO) and epoxidized natural rubber (ENR) comprising 12 wt % of LiClO 4 were studied. Two glass transition temperatures, corresponding to the T g s of the constituents, confirm immiscibility of the polymers over the entire composition range. It turns out that the T g s of both polymers slightly increase after addition of salt to the blends. This shift is approximately constant over the whole range of blend composition. Accordingly, T g measurements reveal that the salt dissolves to approximately equal relative amounts in the two phases. The degree of crystallinity of PEO in blends with ENR descends only to a minor extent with ENR content. However, addition of salt leads first to decreasing crystallinity and second this decrease becomes more pronounced with the addition of ENR. It shows that under these experimental conditions the salt content in PEO increases as compared to ENR. As one expects, the rate of isothermal crystallization does not change in blends as long as PEO is in excess. The situation changes again when salt is added. The rate decreases in a certain range of crystallization temperatures when ENR is added, demonstrating that salt is favorably dissolved in PEO. Conductivity was measured in polymers comprising different salt concentrations. A power-law dependence of conductivity on salt concentration was found. It results that the mobility of charge carriers in PEO exceeds that of ENR by five orders of magnitude. Therefore, the conductivity in blends is primarily governed by PEO as long as PEO is in excess. Conductivity measurements reveal again that salt is preferably dissolved in PEO. The distribution coefficient is estimated.

On Thermal and Spectroscopic Studies of Poly(ethylene oxide)/Poly(methyl methacrylate) Blends with Lithium Perchlorate

“…Hence, not only homopolymers have been used as polymer host, but also polymer blends, [8][9][13][14] block copolymers, [15] polymer composites [16] etc. in an effort to enhance the conductivity of SPEs.…”

“…Ion conductivity (s DC ) of PEO SPEs is mainly ruled by the ion mobility and ion concentration in the amorphous phase of these systems. [6][7][8][9] PEO consists of $ 60% of crystalline phase at room temperature. [10] Thus, PEO-based SPEs suffer low conductivity ($ 10…”

“…[9,11,12] Efforts for improvement of polymer-salt solutions point preferably towards two closely related directions, enhancement of both carrier density and mobility. Most of the binary systems of polymer and salt do not exhibit sufficiently high ion conductivity ($10…”

Thermal Properties and Morphology of Compatible Poly(ethylene oxide)/Natural Rubber‐graft‐poly(methyl methacrylate) Blends

“…We focus on a polymer blending approach here. Blending of PEO with epoxidized natural rubber (ENR) with addition of inorganic salt improves the ionic conductivity (σ DC ∼ 10 −5 S cm −1 at 25 °C) as compared to PEO and inorganic salt system at same salt concentration (σ DC ∼ 10 −6 S cm −1 at 25 °C) . However, these studies do not report on the mechanical properties and it is expected that the PEO/ENR/salt systems suffer from poor mechanical properties due to immiscibility of the components.…”

Thermal Properties and Conductivity of Thermally Treated Epoxidized Natural Rubber‐Based Solid Polymer Electrolytes

“…It possesses low glass transition temperature (e.g. T g of ENR‐50 is −21 °C) and epoxide group which may coordinate with cation of the inorganic salt added . This qualifies it as one of the potential candidates of solid polymer electrolytes (SPEs) host for ion‐rechargeable battery application.…”