Polymer/layered silicate nanocomposites: a review from preparation to processing

This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer matrices is covered, i.e. thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young’s modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy.

Polymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials

Complexation Thermodynamics of Cyclodextrins.

http://dns2.asia.edu.tw/~ysho/YSHO-English/1000%20WC/PDF/App%20Cla%20Sci15,%2011.pdf

Polymer-layered silicate nanocomposites: an overview

The gas sensors fabricated by using conducting polymers such as polyaniline (PAni), polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.

/pdf/gas-sensors-based-on-conducting-polymers-4l6i49715q.pdf

Gas Sensors Based on Conducting Polymers

The coprecipitation of Sr2+ with calcite at 25°C and 1 atm

A compact general theory for the effect of Heisenberg spin exchange on ESR linewidths and saturation parameters is detailed. The effects of Heisenberg exchange on the linewidths of the tetracyanoethylene anion (TCNE−) radical and the di‐tert‐butyl nitroxide (DTBN) radical in both dimethoxyethane (DME) and tetrahydrofuran (THF) are investigated. From comparative studies of linewidth as a function of temperature and of radical concentration, TCNE− in DME is shown to undergo strong exchange with a second‐order rate constant of 4.1 ± 0.6 × 109M−1·sec−1 at 15°C. The TCNE− radical in THF exhibits an anomalous concentration‐dependent linewidth effect when compared to the theory and to the experiments employing DME as the solvent. The uncharged DTBN radical shows similar spin‐exchange properties in both solvents. Possible mechanisms for the anomalous linewidth effect are discussed. The effect of spin exchange on the saturation parameters of the TCNE− radical in DME is investigated in detail, and the experimental ...

Studies of Heisenberg Spin Exchange in ESR Spectra. I. Linewidth and Saturation Effects

The coprecipitation of manganese(II) with calcite: an experimental study

Mode of incorporation of Sr2+ in calcite: Determination by X-ray absorption spectroscopy

A new type of micromechanical sensor has been developed that incorporates piezoresistive microcantilevers, such as those used in scanning force microscope (SFM) instruments. In these devices, the microcantilever is in direct contact with an active sensing material, which may be a common organic polymer or a biologically active sensing layer. Upon analyte exposure, the cantilever directly measures the swelling or volume expansion experienced by an active sensing material. Individual microcantilever sensors may be incorporated into an array in which pattern recognition techniques are used to identify a wide variety of chemical or biological analytes. In addition, these devices are compact, lightweight, and require only simple, inexpensive support electronics.

Michael P. Eastman

Papers

The coprecipitation of Sr2+ with calcite at 25°C and 1 atm

Studies of Heisenberg Spin Exchange in ESR Spectra. I. Linewidth and Saturation Effects

The coprecipitation of manganese(II) with calcite: an experimental study

Mode of incorporation of Sr2+ in calcite: Determination by X-ray absorption spectroscopy

Sensor based on piezoresistive microcantilever technology