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Mitchell Anthamatten, University of Rochester
Normal 0 false false false MicrosoftInternetExplorer4 The objective of this research was to explore how end-associating polymers influence the phase behavior of binary (polymer polymer) blends. The scope of this research includes theoretical and experimental aspects of the kinetics and thermodynamics of polymer-polymer demixing. Understanding how supramolecular bonding in solution and the melt affects physical properties and the phase behavior of these hybrid systems is the key to reducing the high processing costs of commodity polymers and will promote new technologies such as thermoplastic elastomers and shape-memory polymers.[1]The final phase of this project aimed to verify our theoretical predictions[2] and focused on the synthesis and phase behavior studies of mono-functional and telechelic polymers that contain ureidopyrimidinone (UPy) hydrogen bonding groups. Copper-mediated atom-transfer radical polymerization (ATRP) followed by atom transfer radical coupling (ATRC) was initiated using a UPy-functionalized initiator. Each initiated chain bears a single UPy group, and coupled chains contain two UPy end groups. Synthesized monofunctional (PS-UPy: 6.0, 10.7, and 25.6 kg/mol) and telechelic polystyrenes (UPy-PS-UPy: 19.0, 51.2 kg/mol) were prepared. A custom-built right-angle light scattering apparatus was designed to study blend turbidity. Turbidity measurements were performed on spin-cast binary melt blends and on ternary blends containing two polymers and a solvent. In general, the presence of UPy-functional end groups was found to decrease polymer-polymer miscibility. For example, the parent blend system of poly(butadiene)-poly(styrene) (PB-PS), was confirmed to exhibit UCST behavior, as reported in the literature. When one component is functionalized, miscibility decreases, however when both components are functionalized, miscibility appears to improve. This feature is not predicted by the free energy model, and is believed to be of a kinetic origin; i.e. demixing is retarded.Philadelphia, and she intends to graduate in the spring. Funds have also been used to support two undergraduate summer research experiences (Mr. James A. Viveros, Ms. Helen Park) and part of Mr. Jiahui Li’s phase behavior studies. Mr. Viveros and Ms. Park are currently attending graduate school at UCLA and Harvard, respectively. Lastly, funds were applied to acquire equipment and chemicals. 1. Li, J. H.; Viveros, J. A.; Wrue, M. H.; Anthamatten, M. Adv Mater 2007, 19, (19), 2851-2855. 2. Anthamatten, M. J Polym Sci Pol Phys 2007, 45, (24), 3285-3299.
The objective of this research was to explore how end-associating polymers influence the phase behavior of binary (polymer polymer) blends. The scope of this research includes theoretical and experimental aspects of the kinetics and thermodynamics of polymer-polymer demixing. Understanding how supramolecular bonding in solution and the melt affects physical properties and the phase behavior of these hybrid systems is the key to reducing the high processing costs of commodity polymers and will promote new technologies such as thermoplastic elastomers and shape-memory polymers.[1]
The final phase of this project aimed to verify our theoretical predictions[2] and focused on the synthesis and phase behavior studies of mono-functional and telechelic polymers that contain ureidopyrimidinone (UPy) hydrogen bonding groups. Copper-mediated atom-transfer radical polymerization (ATRP) followed by atom transfer radical coupling (ATRC) was initiated using a UPy-functionalized initiator. Each initiated chain bears a single UPy group, and coupled chains contain two UPy end groups. Synthesized monofunctional (PS-UPy: 6.0, 10.7, and 25.6 kg/mol) and telechelic polystyrenes (UPy-PS-UPy: 19.0, 51.2 kg/mol) were prepared.
A custom-built right-angle light scattering apparatus was designed to study blend turbidity. Turbidity measurements were performed on spin-cast binary melt blends and on ternary blends containing two polymers and a solvent. In general, the presence of UPy-functional end groups was found to decrease polymer-polymer miscibility. For example, the parent blend system of poly(butadiene)-poly(styrene) (PB-PS), was confirmed to exhibit UCST behavior, as reported in the literature. When one component is functionalized, miscibility decreases, however when both components are functionalized, miscibility appears to improve. This feature is not predicted by the free energy model, and is believed to be of a kinetic origin; i.e. demixing is retarded.
Philadelphia, and she intends to graduate in the spring. Funds have also been used to support two undergraduate summer research experiences (Mr. James A. Viveros, Ms. Helen Park) and part of Mr. Jiahui Li’s phase behavior studies. Mr. Viveros and Ms. Park are currently attending graduate school at UCLA and Harvard, respectively. Lastly, funds were applied to acquire equipment and chemicals.
1. Li, J. H.; Viveros, J. A.; Wrue, M. H.; Anthamatten, M. Adv Mater 2007, 19, (19), 2851-2855.
2. Anthamatten, M. J Polym Sci Pol Phys 2007, 45, (24), 3285-3299.
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