Synthesis Of Dopa Derivatives And Its Application In Adhesive Bonding

Adhesive bonding is a kind of interfacial behavior. Under ordinary circumstances, the durability of adhesive joints may be affected by the environments in the variety ways. Especially, the major and most common hazard is the effect of water. 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. MAPs exhibit universal adhesion, strong water resistant adhesion, and non-toxic property, which show open opportunities in surface chemistry as primer adhesive coating for surface modification and in biomedical application as tissue adhesive and cement.In the first part of this study, N-Benzyloxycarbonyl-3,4-Dibenzyloxyphenylalanine was selected as target product. A simplified and promising route for synthesis of N-Benzyloxycarbonyl-3,4-Dibenzyloxyphenylalanin is developed and gave a yield of 65.6%. The chemical structures of the N-Benzyloxycarbonyl-3,4-Dibenzyloxyphenylalanine were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Hydrogen-1 Nuclear Magnetic Resonance (1H NMR).The synthesis of poly (N-Benzyloxycarbonyl-3,4-Dihydroxyphenylalanine) (PNBD) was investigated in the second part of this study. A previously reported research was redefined, and the preparation condition of PNBD was optimized. The productivity was 62%. The PNBD was characterized by FT-IR,1H NMR and Gel Permeation Chromatography (GPC).In the last part of this study, the application of PNBD in lap shear tensile strength test and composited with montmorillonoid layers were investigated. In the lap shear tensile strength test, stainless steel was picked as test model at first. The molecular weight of PNBD which shows the highest tensile strength in the adhesive test was screened through preliminary experiment. Secondly, the effect of key bonding variables such as dosage of PNBD, cure time and cure temperature on the adhesive performance were investigated in detail. The optimal bonding process was obtained through the above experiments and listed as follows:weight-average molecular weight of PNBD 3600 g/mol, thickness of PNBD 0.06 mm, cure time 24 h, cure temperature 80℃. Thirdly, many different kinds of materials were tested this bonding process, such as copper, aluminum, PMMA, PS and PE. According to this optimal process, the metal adherends formed a higher adhesive bond than the plastics. As to the metal adherends, the tensile strength of copper was the highest, reached up to 2.43 MPa; and the stainless steel was lower than the others, got 2.05 MPa. As to the plastic adherends, the tensile strength of PE was the lowest, only got 0.50MPa. The tensile strength of PMMA was much better than the other plastic adherends, reached to 1.19 MPa, although less than the metals. In the application of PNBD composited with montmorillonoid layers, the experimental results show that the PNBD-montmorillonite composite membrane'has better mechanical properties and tensile strength than the pure montmorillonite clay.