Transport Properties Of Polymers Research Articles

Material selection considerations for gas separation processes

AbstractAdvantages and disadvantages associated with common membrane types used in gas separation operations are reviewed. Comparisons between dense‐walled and several different types of asymmetric structures are made. In addition to overall membrane structure, the molecular natures of different membrane material types are treated. Tradeoffs between the use of rubbery and glassy polymers are considered first, followed by a treatment of the optimization of glassy membrane permeability and permselectivity properties. Material optimization principles are defined in terms of the basic thermodynamic solution and kinetic transport properties of polymers, and applications of these principles are illustrated for a modified poly(phenylene oxide) and a homologous series of polyimides derived from pyromellitic dianhydride.

Synthesis and Electronic Transport Properties of Polymers and Copolymers of β- N- Carbazolylethyl Vinyl Ether

Synthesis and Electronic Transport Properties of Polymers and Copolymers of β- N- Carbazolylethyl Vinyl Ether

The Thermal Transport Properties of Polymers

Abstract Values of thermal diffusivity and thermal conductivity are needed for heat-flow calculations, for the determination of structure-property relationships, and for material selection and comparison. However, all aspects are hampered by a dearth of reliable data and anything more than a superficial glance at the literature is apt to be discouraging for the uninitiated. Hardly any thermal diffusivity data exist, and the reported values of thermal conductivity show very large scatter. The present state of confusion can be seen, for example, in Figures 1 and 2, which show the reported thermal conductivity values for polystyrene and gum natural rubber. Not only do the values differ at some temperatures by more than 100%, and in the case of rubber by almost 300%, but different trends are indicated throughout the temperature range. Discrepancies of this size cannot be due to sample variations, and they give some indication of the experimental difficulties associated with thermal property measurements.