Studies On Synthesis And Property Of Mussel Mimetic Polyurethane

Mussel adhesive proteins (MAPs) secreted by marine mussels allow themselves to anchor tenaciously to all types of inorganic and organic surfaces in a wet and turbulent environment, such as metal, glass, polymer, and mineral surfaces, even including adhesion-resistant poly (tetrafluoroethylen). MAPs exhibit universal adhesion, strong water resistant adhesion, and non-toxic property, which show open opportunities in national defense and ocean engineering yield as water resistant sealant and adhesive for ships or submarines, in biomedical application as soft tissue adhesive and hard tissue cement, and in surface chemistry as primer adhesive coating for surface modification. However, this kind of mussel adhesive was confined by ultra-low production, complex technology, and high cost through extraction or recombinant DNA approach.On the basis of principles learned from nature, it is possible to prepare a mimetic adhesive polymeric material with low cost and high property when combining the unique adhesion of marine adhesive proteins with the designability, easy synthesis, and low cost of simple polymer. Two kinds of dopamine-containing mussel mimetic polyurethanes were prepared in this thesis. Mussel mimetic polyurethane with dopamine in side chains was synthesized by acylation reaction of carboxyl-containing polyurethane and dopamine, while mussel mimetic polyurethane with dopamine in end groups was prepared by coupling reaction of NCO-terminated urethane prepolymer and dopamine. The related properties were studied when they were used as adhesive or primer coating.For mussel mimetic polyurethane with dopamine in side chains, polyurethane backbone was used to take the place of polyamide chain in the mussel adhesive protein and dopamine was appended to the polyurethane to mimic the strong adhesion of mussel adhesive proteins. The successful incorporation of dopamine with polyurethane was confirmed by FTIR, 1H-NMR and UV-vis. The results of TGA show that the decomposed temperatures were improved for 20oC when dopamine was introduced to polyurethane. The shear adhesive strength was characterized by universal tensile machine, and the adhesive mechanism of the mimetic polyurethane was also studied by UV-vis and rheology analysis. Results show that dopamine appended to polyurethane by amide linkage exhibited universal adhesion just like MAPs. The adhesive strength for metal, glass, and polymer was greatly enhanced when a little mount of dopamine was grafted (about 2wt%). The adhesion and cohesion were improved at the same time. For the substrate of Fe, the adhesive strength of mussel mimetic polyurethane with molecular weight at 8800, 17400, and 34500 were respectively 2.1MPa, 3.5MPa, and 5.2MPa, which can be respectively compared with the adhesive strength of mussel mimetic polypeptide with molecular weight at 98k, 186k, and 255k.For mussel mimetic polyurethane with dopamine in end groups, the structure was confirmed by FTIR, 1H-NMR, UV-vis and GPC. The results also show that it was efficient to incorporate dopamine with polyurethane by NCO coupling reaction, rather than by acylation reaction. Contact angle results show that mussel mimetic polyurethane with dopamine in end groups can attach to a variety of surfaces, and can be used as a primer adhesive coating for surface modifaction.