https://pure.rug.nl/ws/files/6693298/2006ProgPolymSciNalawade.pdf

Supercritical carbon dioxide as a green solvent for processing polymer melts: Processing aspects and applications

Application of electrochemical impedance spectroscopy to commercial Li-ion cells: a review

Supercritical carbon dioxide (scCO2) is a unique solvent with a wide range of interesting properties. This review focuses upon recent advances in the use of scCO2 in materials synthesis and materials processing. In particular, we consider the advances made in three major areas. First the design and application of new surfactants for use in scCO2, which enable the production of metal nanoparticles, porous polymers and polymers of high molecular weight with excellent morphology. Second the development of new polymer processing and polymer blend technologies in scCO2, which enable the synthesis of some very complex polymer composites and blends. Finally, the application of scCO2 in the preparation of novel biomedical materials, for example biodegradable polymer particles and scaffolds. The examples described here highlight that scCO2 allows facile synthesis and processing of materials, leading to new products with properties that would otherwise be very difficult to achieve.

Materials processing in supercritical carbon dioxide: surfactants, polymers and biomaterials

A subject for the invention is to improve the cycle characteristics of a high-capacity secondary battery containing an active material packed at a high density, by using a particulate active material having a low aspect ratio. The invention relates to a nonaqueous-electrolyte secondary battery comprising a negative electrode and a positive electrode each capable of occluding/releasing lithium, a separator, and a nonaqueous electrolyte solution comprising a nonaqueous solvent and a lithium salt, characterized in that the separator comprises a porous film made of a thermoplastic resin containing an inorganic filler, and at least either of the following is satisfied: the active material contained in the negative electrode is a particulate active material having an aspect ratio of from 1.02 to 3; and the active material contained in the positive electrode is a particulate active material having an aspect ratio of from 1.02 to 2.2.

Nonaqueous electrolyte secondary battery

A mechanically robust and ion-conductive polymeric coating containing two polymers, polyethylene glycol tert-octylphenyl ether and poly(allyl amine), with four tailored functional groups is developed for graphite and graphite-Si composite anodes. The coating, acting as an artificial solid electrolyte interphase, leads to remarkable enhancement in capacity reversibility and cycling stability, as well as a high-rate performance of the studied anodes.

A Mechanically Robust and Highly Ion‐Conductive Polymer‐Blend Coating for High‐Power and Long‐Life Lithium‐Ion Battery Anodes

The influence of microscale fillers on ethylene–propylene rubbers (EPR) was examined with respect to their vibrational damping capacity and viscoelastic properties. The vibrational damping and dynamic mechanical properties of reinforced EPR were studied in systematic and comparative ways that reinforced the evidence of a direct relation between the vibrational damping loss factor and its mechanical damping loss factor. In this study, the sensitivity of the vibrational damping loss factor of reinforced EPR was quantified with respect to the variation in thickness, filler type, and filler content. Dynamic mechanical relaxation behaviors were also analyzed. The viscoelastic properties in terms of the storage modulus, loss modulus, mechanical damping loss factor, and frequency dependence of molecular relaxation showed interesting results with the filler types and compositions that had good correspondence with the vibrational damping behaviors. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3058–3066, 2001

Characterization of the vibrational damping loss factor and viscoelastic properties of ethylene-propylene rubbers reinforced with micro-scale fillers

To achieve fast ion transport in poly(ethylene oxide) (PEO)-based polymer electrolytes, we aimed to increase the ionic conductivity by using supercritical carbon dioxide (scCO2) as a processing solvent. In the crystalline PEO−LiCF3SO3 complex system, a large difference was observed in the conductivities of the original and scCO2-treated samples. In particular, PEO7-LiCF3SO3 (oxyethylene unit:Li = 7:1) increased in conductivity approximately 100-fold at 40 °C with scCO2 processing to a value of 1.8 × 10-5 S/cm. Differential scanning calorimetry measurement showed that the processing reduces the glass transition temperature (Tg), the melting point of the PEO crystalline phase (Tm1), and the heat of fusion of the crystalline complex part (ΔH2). Raman scattering analysis clearly confirmed the decrease in the triple ion fraction and the increase in the ion pair fraction in scCO2-treated samples. Furthermore, subsequent time dependence of the ionic conductivity shows that scCO2 processing maintains the conducti...

Effect of Supercritical Carbon Dioxide Processing on Ionic Association and Conduction in a Crystalline Poly(ethylene oxide)−LiCF3SO3 Complex

The cure behavior and the reaction kinetics of an anhydride-cured epoxy resin catalyzed by cationic thermal latent initiator, N-benzylpyrazinium salts, have been investigated by a near-infrared (NIR) spectroscopy. The spectral changes are interpreted in terms of the mechanism of cure. NIR absorption bands are due to protons connected to carbon, nitrogen, and oxygen. In this work, the homogeneous model system involves a simple addition reaction mechanism leading to an exothermic reaction between epoxide and anhydride activated groups. A comprehensive account of the origin, location, and shifts during reaction of all major NIR absorption peaks in the spectral range from 4000 to 7100 cm -1 is provided. The extent of reaction is calculated from NIR absorption band at 4530 cm -1 , which depends on epoxide concentration. The utility of NIR spectroscopy to study the kinetics of epoxy cure reaction has been established. Consequently, absorbencies in the NIR spectra suitable for quantitative studies of epoxy resin reaction kinetics have been identified.

Gun-Ho Kwak

Papers

Characterization of the vibrational damping loss factor and viscoelastic properties of ethylene-propylene rubbers reinforced with micro-scale fillers

Effect of Supercritical Carbon Dioxide Processing on Ionic Association and Conduction in a Crystalline Poly(ethylene oxide)−LiCF3SO3 Complex

Cure and reaction kinetics of an anhydride‐cured epoxy resin catalyzed by N‐benzylpyrazinium salts using near‐infrared spectroscopy

Effects of anode active materials to the storage-capacity fading on commercial lithium-ion batteries

Improvement of the ionic conductivity for amorphous polyether electrolytes using supercritical CO2 treatment technology