ABSTRACT
Dispersity ................................................................................... 226 11.2.3 Molar Mass Dispersity (distribution) ........................................ 229 11.2.4 Polymer Solutions ..................................................................... 233
11.3 List of Methods for Determination of Molecular Characteristics of Polymers ................................................................................................ 239 11.3.1 Mean (average) Values of Polymer Molar Masses ................... 239 11.3.2 Mean (average) Values of Chemical Structure and Physical
Architecture of Polymers ........................................................... 240 11.3.3 Molar Mass Dispersity (distribution) ........................................ 240 11.3.4 Chemical Structure Dispersity .................................................. 240 11.3.5 Physical Architecture Dispersity .............................................. 240 11.3.6 Simultaneous Determination of Dispersity in Molar Mass
and in Chemical Structure or in Molecular Architecture .......... 241 11.4 Separation Methods for Synthetic Polymers .......................................... 241
11.5 Chromatography of Synthetic Polymers ................................................ 243 11.5.1 General Considerations and Basic Terms.................................. 243 11.5.2 Processes in Columns for Polymer HPLC – Retention
Mechanisms .............................................................................. 246 11.5.3 Separation Arrangements in Polymer HPLC ............................ 262
11.6 Instrumentation and Materials for Polymer HPLC ................................ 264 11.6.1 Apparatus for Polymer HPLC ................................................... 264 11.6.2 Mobile Phases for Polymer HPLC ............................................ 277 11.6.3 Macromolecular Standards for Polymer HPLC ........................ 282
11.7 Size Exclusion Chromatography ............................................................ 283 11.7.1 General Considerations ............................................................. 283 11.7.2 Retention Mechanisms and Accompanying Processes in SEC . 284 11.7.3 Instrumentation and Materials for SEC ................................... 290 11.7.4 Applications of Size Exclusion Chromatography ..................... 296 11.7.5 Advantages, Limitations and Drawbacks of SEC .................... 298
11.8 Coupled Methods of Polymer HPLC ..................................................... 303 11.8.1 General Considerations ............................................................. 303 11.8.2 Enthalpy Driven Polymer HPLC .............................................. 304 11.8.3 Liquid Chromatography Under Critical Conditions of
Enthalpic Interactions ............................................................... 304 11.8.4 Eluent Gradient Polymer HPLC .............................................. 310 11.8.5 Temperature Gradient Polymer HPLC ...................................... 313 11.8.6 Liquid Chromatography Under Limiting Conditions of
Enthalpic Interactions ................................................................ 314 11.8.7 Enthalpy Assisted SEC .............................................................. 321
11.9 Two-dimensional Polymer HPLC ......................................................... 322 11.10 Conclusion ........................................................................................... 328 Keywords .......................................................................................................... 329 Acknowledgment .............................................................................................. 329 References ......................................................................................................... 329
11.1 MOLECULAR CHARACTERIZATION OF SYNTHETIC POLYMERS
Polymers belong to the group of macromolecular substances. They are comprised of one or several kinds of repeating units called mers interconnected with chemical bonds and ordered according to certain statistics. Some macromolecular substances are built from the low-molecular moieties, mutual arrangement of which can be hardly described by any statistics (for example humin substances). The latter should not be designated “polymers”. In other words, all polymers are macromolecular substances but not all macromolecular substances are polymers. In this chapter, we will deal almost exclusively with synthetic and man-made polymers. The important exceptions represent polysaccharides, especially cellulose and its derivatives. Cellulose is the most abundant organic polymer on the earth. The behavior of polysaccharides in many aspects resembles that of synthetic polymers. Polysaccharides are often chemically modified to adjust both their solubility and utility properties. Chemical modification of polysaccharides results in the specific class of natural/synthetic polymers.
