Date of Award
Master of Science (MS)
Materials Science and Engineering
Dr. O. Thompson Mefford
Dr. Jiro Nagatomi
Dr. Igor Luzinov
Hydrogel adhesives are a new class of materials with excellent biocompatibility, which makes them very attractive for biomaterial applications. It has been previously shown that Tetronic T1107, a four-arm poly (propylene oxide)-poly (ethylene oxide) (PPO-PEO) block copolymer, is useful as a chemical crosslinking thermo-responsive hydrogel for bioadhesive applications. The end groups of this polymer are modified with acrylate and N-hydroxysuccinimide (NHS) functional groups. The acrylate end group gives the polymer cohesive properties with long-range chemical crosslinking using dithiothreitol (DTT), while the NHS end group gives the polymer adhesive properties through bonding with amines found in organic tissue. It was found that one reagent used in the T1107 modification protocol, 4-methoxyphenol, was inhibiting the succinic anhydride modification, preventing proper modification of the protocol. DSC and rheology demonstrated that there is not a correlation between acrylation rate and phase transition temperature, implying that the temperature is a bulk property gained from the polymer backbone. It was also found that the modified polymer will undergo spontaneous crosslinking between acrylate groups if stored at sufficiently elevated temperatures. Lastly, it was found that the polymers synthesized using certain lots of T1107 did not gelate at homeopathic temperatures. It was found that T1107 polymer, as received, exhibited a bimodal distribution in GPC, indicating the presence of a smaller molecular species. The polymer did not show appreciable amounts of volatiles, yet NMR indicates the presence of different molecular structure between different lots of T1107.
Mayfield, Alexander, "Characterization of Thermal Gelation Properties in Bioresorbable Thermally Activated Hydrogel Polymers for Hernia Surgery Applications" (2022). All Theses. 3862.