Synthesis and Characterization of Ionically Crosslinked Networks
Author | : Qinyuan Chai |
Publisher | : |
Total Pages | : 77 |
Release | : 2013 |
Genre | : Chemical bonds |
ISBN | : |
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The overall goal of this thesis was to investigate the synthesis and characterization of elastomeric polymer networks crosslinked by ion-pairs. To generate these networks, cationic polyacrylate ionomers with styrene sulfonate counter-ions were synthesized. These polymers were used to generate ionically crosslinked networks by copolymerization of the pedant vinyl ionomers with acrylate monomer. These ionically crosslinked elastomers swelled in organic solvent like covalently crosslinked elastomers, but could be dissolved and re-gelled by dissociating and re-associating the ionic bonds by double ion-exchange reactions under acidic and basic conditions. Uniaxial tensile testing and oscillatory shear rheology were used to characterize the mechanical properties of the materials and compared to covalently crosslinked control samples. In contrast to the covalently crosslinked polymers, the ionically crosslinked samples showed strong property dependence on temperature and level of strain. At room temperature, the ionically crosslinked polymer had similar properties with a covalently crosslinked elastomer. As the temperature was increased above 100°C, the fluid-like property became more and more obvious due to the rearrangement of the ionic bonds. In addition, under load the ionically crosslinked polymer also exhibited flow. This mechano-chemical response of the materials to reconfigure the network under thermo-mechanical load should provide opportunities for developing new processable and self-healing elastomers using ionic interactions.