| Summary: | Proceedings (senza ISBN) del Congresso "XVIth European Seminar on Applied Thermodynamics", Pont-à-Mousson (F), 19-22 giugno 1997. - Polycarbonates (PC) are a special class of polyesters derived from the reaction of carbonic acid derivatives with aromatic, aliphatic, or mixed diols. They may be produced by the Schotten-Baumann reaction of phosgene with a diol in the presence of an appropriate hydrogen chloride acceptor or by melt transesterification reaction between the diol and a carbonate ester. Extreme toughness, transparency, resistance to burning, maintenance of useful engineering properties over a temperature range from -200 to +140°C are the outstanding features of Polycarbonates. This balance of properties qualifies Polycarbonates for high-tech applications: bubble helmets for astronauts; break resistant windows for buildings, buses, trains; impact-resistant lenses for lighting; their good optical properties made Polycarbonates the materials which are mostly used to produce optical disks (CD). The solution of these problems is very complex and gas chromatography has often been employed to solve them, since it provides useful information about thermodynamics of polymer systems and allows to determine experimentally the parameters characterising polymers in presence of solvents. In this work, a sample of Bisphenol A Polycarbonate was studied by Inverse Gas Chromatography (IGC): the weight activity coefficients at infinite dilution and the Flory-Huggins parameter for paraffinic and aromatic solvents have been determined. Two thermodynamic models (UNIFAC-FV and GC-FLORY EOS) were then used and compared with the experimental data.
|
|---|