| Marine biofouling is formed by the adhesion,growth and accumulation of marine organisms on submerged equipment surfaces.It brings a number of problems to human's exploration and utilization of marine resources.Currently,silicone based fouling release coatings(FRC)and tin-free self-polishing coatings(SPC)have bee used to combat marine biofouling.However,both the fouling removal of FRC and the self-renewal of SPC require a strong water flow,leading to their limited antifouling efficiency under static conditions.Moreover,FRC has poor mechanical strength and low adhesion to substrates while SPC is not very eco-friendly.In this thesis,we syntheized silicone based polyurethane with grafted antifoulants,crosslinked silicone elastomer with grafted fluorinated antifoulant chains and poly(silyl methacrylate)-polyester with grafted antifoulants and studied their properties.The main results are as follow:(1)We prepared polydimethylsiloxane(PDMS)based polyurethane with grafed antifoulant 2,4,6-trichlorophenyl maleimide(TCM)via thiol-ene addition and polyaddition reactions.The polymer coating has low surface energy and hydrophobicity.X-ray photoelectron spectroscopy(XPS)demonstrates the distribution of some antifoulant groups on the surface,and the surface composition is stable after immersion in artificial seawater(ASW).Moreover,dynamic mechanical analysis and adhesion test show that the coating has good mechaincial properties.Laboratory bioassays prove that the polymer coating can effectively inhibit the adhesion of bacteria,diatom and barnacle cyprids thanks to the presence of antifoulant groups on the surface.Marine field test shows that the joint effect of low surface energy and the antifoulant groups endows the material with excellent antifouling ability.(2)We synthesized a terpolymer of 2,4,4-trichloro-2-hydroxydiphenyl ether acrylate(TCSA),dodecafluoroheptyl methacrylate and methacryloxypropyltrimethoxysilane and use it to react with silanol terminated PDMS,obtaining a crosslinked coating.XPS result shows that the antifoulant telomer can be enriched on the coating surface due to the strong surface segregation ability of dodecafluoro chains.Contact angle test,DMA and atomic force microscopy reveal that the material has low surface energy and low elastic modulus,which leads to its excellent fouling release performance.Laboratory bioassays on bacteria and diatom and marine field test prove that the PDMS based coating with surface-enriched antifoulant chains has excellent antifouling ability.(3)We synthesized a series of poly(methacrylate)-polyester copolymers by racdical ring opening copolymerization of silyl methacrylate(SiMA)and 2-methylene-1,3-dioxepane(MDO).Si MA has a higher reaction rate and reactivity ratio than MDO,and the copolymerization is a first-order reaction.Studies on the properties of the copolymers after immersion in ASW by NMR,contact angle,water absorption and gel permeation chromatography reveal that the main-chain ester bonds in the copolymer can degrade and the silyl side groups can hydrolyze.The chemical structure of silyl groups can profoundly influence the self-polishing property.The copolymer of bis(trimethylsiloxy)methylsilyl methacrylate(MATM2)and MDO has a high hydrolysis and degradation rate.Antifoulant TCSA was introduced to the system to prepare a TCSA-MATM2-MDO terpolymer.The polymer coating has a good adhesion to the substrate and the coating surface swiftly changes from hydrophobic to hydrophilic after immersion in ASW due to the hydrolysis of silyl groups.Gravimetry test demonstrates that the samples with higher MDO content show higher mass loss but lower water absorption.Laboratory bioassays on bacteria and diatom show that the grafted TCSA provides fouling resistance,which enhances with the TCSA content. |
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