ABSTRACT
In recent years, the application of modied polysulfones (PSFs) in pharmaceutical, chemical, and food industries, as well as in biotechnology, has become a topic of special scientic interest. Modication of PSFs is mostly based on the addition of carboxylic, chloromethylic, or chlorosulfonic groups to the aromatic ring [1-7]. PSFs t well into the category of super engineering plastics, due to their excellent thermal stability, good resistance to inorganic acids and bases, and an outstanding hydrolytic stability against hot water and steam sterilization. Chain rigidity is derived from
6.1 Introduction .................................................................................................. 157 6.2 Dielectric Relaxation Phenomena in Complex Systems ............................... 159 6.3 Optical Properties in Complex Systems ....................................................... 164 6.4 Origin of Dielectric Relaxation in Modied PSFs ....................................... 172
6.4.1 Establishment of Complex Polymer Conformations by Computational Methods............................................................... 172
6.4.2 AC-Dielectric Measurements at Different Frequency and Temperature Values .......................................................................... 174
6.4.3 Inuence of Frequency and Temperature on Dielectric Loss ........... 177 6.4.4 Enthalpic and Entropic Contributions of Activation Energy
on γ- and β-Relaxation Processes ..................................................... 180 6.5 AC Conductivity ........................................................................................... 185 6.6 Impedance Spectroscopy .............................................................................. 190 6.7 General Remarks .......................................................................................... 193 References .............................................................................................................. 194
the relatively inexible and immobile phenyl and SO2 groups, whereas their toughness is derived from the connecting ether oxygen. The presence of these groups enhances their electrical and thermal stability, oxidation resistance, and rigidity even at high temperatures. Thus, their derivatives appear as important topics of scientic research from both theoretical and practical viewpoints, with special reference to their applications areas [8,9].
