Dynamic polymers are a new class of polymers known for their physical properties such as adaptability, self-healing, shape-memory, stimuli-responsiveness, and enhanced recyclability. Dynamic polymers respond to biochemical stimuli and physicochemical stimuli such as pH, light, electric field, temperature, and pressure. Dynamic properties in polymer materials can be due to either dynamic covalent bonds or non-covalent interactions. There is not much literature on dynamic and self-healing carbon nanotube (CNT) reinforced bulk materials with the polymer matrix precisely engineered by RAFT polymerization so the technique is not well understood amongst dynamic polymers. This research focuses on dynamic polymers with Diels-Alder (DA), epoxies, and hydrogen bonds in self-healing polymers created by RAFT polymerization with three blocks and three dynamic chemistries playing distinct dynamic roles to see if CNT would show significant reinforcement in all the chemistries. Three strains of polymers embedded with CNT were made with the terminal end of the polymer having a furan group, an epoxy group, and an UPy group. Afterwards, size exclusion chromatography was done to measure the size and dispersity of molecules in the polymers. The mechanical and self-healing properties of the polymers were tested as well. Efficient nano-reinforcement was achieved using <1 wt.% multi-walled carbon nanotubes (MWCNT). Resulting composites showed excellent self-healing with over 3 MPa increase in stress and 4 MPa increase in Young’s modulus compared to unreinforced materials. Effective reinforcement was found using FMA but not found in polymers with epoxy groups with N,N-dimethylethylenediamine or UPy only materials with supramolecular dynamic quadrupole H-bonding.
Author: Derrick Dunn, Biochemistry
Advisor: Dominik Konkolewicz Chemistry
Graduate Advisor: Obed Dodo, Chemistry
You must be logged in to post a comment.