Type of Document Thesis Author Haidar Ahmad, Imad Amin Author's Email Address email@example.com URN etd-06182008-191146 Title Dilute Solution Properties of Copolymers Degree Master of Science Department Chemistry and Biochemistry, Department of Advisory Committee
Advisor Name Title Andre Striegel Committee Chair Joseph B. Schlenoff Committee Member Oliver Steinbock Committee Member Keywords
- Light Scattering
- Refractive Index
- Intrinsic Viscosity
- Mark-Houwink Plot
- Second Virial Coefficient
- Light Scattering
Date of Defense 2008-03-20 Availability unrestricted AbstractCopolymers comprise two different functionalities within one chain, arranged in different patterns according to the type of copolymer: Diblock, alternating, or random. The presence of these two different functionalities within the same chain enriches the copolymer properties and applications, and affects the copolymeric end-use properties. Copolymers are easily studied in dilute solution because otherwise interchain repulsion will be likely manifested.
In this study, size-exclusion chromatography (SEC) is coupled to multi-angle light scattering, viscometry, and refractometry detectors. From the wealth data produced from this triple-detector SEC system, we obtain information about the composition of the copolymers, their shape and size in solution, and their molar mass distribution.
In a controlled set of experiments, we characterize block, random, and alternating copolymers of polystyrene and poly(methyl methacrylate), as well as the constituent homopolymers. Different polymeric and copolymeric properties are studied using the triple detector system, such as: 1) The bulk percentage composition of copolymers is successfully calculated using an equation that relates the refractive index increments of the copolymer to that of the comprised homopolymers. This equation was derived for block copolymers, and we effectively extended its use to calculate the composition of the random and alternating copolymers as well. 2) Factors affecting the goodness of a solvent for copolymers are explained using their corresponding thermodynamic parameter. 3) The structure of the copolymers in solution is studied using relationships between either the radius of gyration and molar mass, or between intrinsic viscosity and molar mass. 4) Other polymeric properties, such as molar mass and molar mass distribution, are also determined.
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