Analytical and statistical approaches in the characterization of synthetic polymers

Polymers vary in terms of the monomer/s used; the number, distribution and type of linkage of monomers per molecule; and the side chains and end groups attached. Given this diversity, traditional single-technique approaches to characterization often give limited and inadequate information about a given polymer. Multi-technique but polymer-specific approach was found to be an appropriate alternative. This strategy was applied in characterizing polymers of a wide range of properties from simple polyethylene gylcol, to polycationic chitosan and aminopropyl based oligosiloxanes, and to polydiverse polyfluorinated polyethoxylates.
Mass Spectrometry (MS) was used to characterize the different polymers. Different modes of sample introduction, ionization, mass analysis and detection were surveyed. The nature of the monomer units, the size and the polydispersity of polymers are the important factors that affect the detection and quantification of the polymer moieties using MS. MS gave information not just on the molecular weight but also about the repeating units of the polymers.
Traditional techniques like size exclusion chromatography and infrared spectroscopy were also used to obtain complementary information on the properties of polymers. Chemometric techniques like partial least squares aided in the statistical evaluation of experimental data.
The research works included in this thesis have demonstrated that polymer characterization can be accomplished with the use of a combination of different instrumental and statistical techniques. This strategy allows the researcher to explore additional information about the polymer formulation and correlate these to some observed behaviors or activities.