[PDF] Diffusion And Equilibrium Measurements In Polymer Solvent Systems By Inverse Gas Chromatography Method eBook

Author : Hülya Eser
Publisher :
Page : 180 pages
File Size : 12,22 MB
Release : 2004
Category : Inverse gas chromatography
ISBN :

GET BOOK

In this study, thermodynamic properties, namely retention volume, infinitely dilute weight fraction activity coefficient, Flory- Huggins interaction parameter, solubility parameters of solute and polymer, partition coefficient and diffusion coefficients of the various solvents in poly (methyl methacrylate co butyl methacrylate) (PMMA co BMA) and poly (lactide co glycolide) (PLGA) at infinite dilution of the solvent have been determined by inverse gas chromatography (IGC). In this technique, a small amount of the solvent was injected into the capillary column and its retention time was measured and used to calculate several polymer-solvent interaction parameters which are mentioned above. The solutes used in this study were methanol, ethanol, propanol, butanol, methyl acetate, ethyl acetate, propyl acetate, dichloromethane, trichloromethane, acetone, methyl methacrylate, butyl methacrylate, water for PMMA co BMA and acetone, dichloromethane, trichloromethane, ethyl acetate, ethyl alcohol, tetrahydrofuran, water for PLGA. The glass transition temperature of the polymers were determined as 106 0C and 42 0C for PMMA co BMA and PLGA respectively by differential scanning calorimetry. Experiments were performed in the range of 150-200 0C for PMMA co BMA and 80-120 0C for PLGA which are above the glass transition temperature of the polymer. The thermodynamic results, obtained from the experiments, indicated that trichloromethane and dichloromethane were the most suitable solutes among all the solvents studied for both of the polymers. The partition (K) and diffusion coefficients (Dp) of various solvents at infinite dilution of the solvent were calculated by using the model developed by Pawlisch et al. (1987). The optimum K and Dp values that best fit the data were found and the model predicted experimental data very well. In summary, IGC method is a powerful tool for the determination of thermodynamic and diffusion properties of solvent in polymer at infinite dilution of the solvent. Vrentas- Duda free volume theory was used to correlate the diffusion data and to investigate the effect of solvent size on diffusion process. The theory has shown to correlate diffusion data above the glass transition temperature very well for the PMMA-co-BMA .solvent system.

Author : R. Vîlcu
Publisher : Elsevier
Page : 212 pages
File Size : 32,18 MB
Release : 2012-12-02
Category : Science
ISBN : 0444597433

GET BOOK

This book presents direct and inverse gas chromatography as a powerful tool for determining a great number of thermodynamic properties and quantities for micro- and especially for macromolecular substances. In order to ensure the continuity and clarity of the presentation, the book first considers some frequently used concepts of chromatography with a mobile gas phase, i.e. the mechanism of separation, retention parameters and the theories of gas chromatography. The employment of this technique as an important method of studying solutions through the most representative statistical models is also discussed. The thermodynamics of direct gas chromatography, as applied to dissolution, adsorption and vaporization underlies the thermodynamic treatment of inverse gas chromatography. The most extensive chapter of the book is devoted to the thermodynamics of inverse gas chromatography and deals with a number of important topics: phase transitions in crystalline-amorphous polymers and liquid crystals, glass transitions, other second order transitions in polymers, the determination of diffusion coefficients, the segregation of block copolymers and other applications.This book is intended for those specialists in research and industry who are concerned with the modification and characterization of polymers, with establishing polymer applications, and with the processing of polymers. It will also be useful to students and specialists interested in the physico-chemical basis of the phenomena involved in gas chromatography in general and its inverse variant in particular.

Author : AllanF.M. Barton
Publisher : Routledge
Page : 772 pages
File Size : 33,70 MB
Release : 2018-05-02
Category : Science
ISBN : 1351442090

GET BOOK

Now available for the first time, this valuable reference presents polymer solubility parameters and various polymer-liquid interaction parameters in an easy-to-use form. It critically evaluates and comprehensively compiles data from original sources. It presents these quantities polymer-by-polymer, alphabetically by polymer common chemical name, fully cross-referenced by systematic chemical names, alternative names and trade names. This one-of-a-kind handbook summarizes the relationship between the various quantities and their methods of determination. This resource is an absolute must for all who are interested in the chemical industry, specifically polymer chemistry, chemical engineering, applied chemistry, and physical chemistry.

Author : Ramon Albalak
Publisher : Routledge
Page : 737 pages
File Size : 37,45 MB
Release : 2017-09-29
Category : Technology & Engineering
ISBN : 1351423592

GET BOOK

This work introduces the fundamental background necessary to understand polymer devolatilization. It elucidates the actual mechanisms by which the devolatilization of polymer melts progresses, and discusses virtually every type of devolatilization equipment available. The work also addresses devolatilization in various geometries and types of equipment, describing the use of falling strand, slit, single-screw, co-rotating and counter-rotating twin-screw devolatilization.