Preparation And Properties Of Silicone Marine Antifouling Coatings

The vast ocean contains rich natural resources.In order to effectively develop and utilize marine resources,large-scale marine facilities were needed,but they will inevitably be infringed by marine organisms in the marine environment.Marine biological fouling has become an urgent problem to be solved in marine development and has also brought huge economic losses.Among them,coating antifouling coating on the surface of marine facilities was the most economical and effective way.However,the eliminated tributyltin(TBT)coating and the widely used copper containing antifouling agent coating will pollute the marine environment,so the development of non-toxic and environmental protection marine antifouling coating was of great significance.Silicone coating was widely favored by people because of its low surface energy,non-toxic,environmental protection and other characteristics.Its low surface energy enables ships to used the scouring of water during navigation,and it was easy to remove dirt.However,under static conditions,it lacks the shear force provided by water flow,and the coating has the problem of insufficient antifouling capacity.In this paper,we synthesized antifouling coatings with both mechanical and static antifouling properties by studying the antifouling mechanism and using silicone macromolecular structure design.The main research contents were as follows:1.An amphiphilic silicone polyurethane marine antifouling coating(PDMS-Pu-Tx%)was synthesized by reacting with isophorone diisocyanate(IPDI)with double ended hydroxypropyl polydimethylsiloxane(PDMS)and polytetrahydrofuran(PTMG)as main chain,1,4-butanediol(BDO)as chain extender,triethanolamine(TEOA)as crosslinker and hydrophilic polymer as side chain.The hydrophilic part was formed by free radical polymerization of N-vinylpyrrolidone(NVP)and butyl acrylate(BA)and functionalized by 3-mercapto-1,2-propanediol(TPG).The results showd that the mechanical strength of amphiphilic silicone polyurethane coating was greater than 14 MPa and the adhesion to the substrate was greater than 1 MPa due to hydrogen bond interaction.In addition,we used Materials Studio software to study the hydrogen bond number(H-bond)and free volume(FFV)of materials from a microscopic point of view.The introduction of hydrophilic side chain improves the hydrophilicity of the coating and maintains a low surface energy.The surface energy was only 24.1mj·m^-2.The coating has good dirt release performance.When the hydrophilic polymer was added to 15 wt%,the antibacterial adhesion efficiency could reach 98%,which can maintain the real sea antifouling performance for a long time.2.Taking double ended hydroxypropyl polydimethylsiloxane(PDMS)as the main chain,1,4-butanediol(BDO)and 3,4-diaminofurazolin(DAF)as the chain extender,7-amino-4-methylcoumarin(AMC)as the end capping agent,and zinc chloride(Zn Cl₂)as the coordination metal ion,a silicone marine antifouling coating(PDMS-DAF-x-AMC)based on the synergistic effect of furazolin and coumarin was obtained by the addition reaction with isophorone diisocyanate(IPDI).The results showd that through hydrogen bond interaction and metal ion coordination,the coating has good mechanical properties(2.78 MPa),and can effectively self repair at 60?,and the self repair efficiency can reach 85%.PDMS-DAF-x-AMC coatings have good hydrophobicity and low surface energy characteristics.In addition,we used Materials Studio software for molecular dynamics(MD)to simulate the hydrogen bond number(H-bond)and coordination bond energy of PDMS-DAF-x-AMC.The antifouling ability of the coating was evaluated by marine bacteria Pseudomonas,and the antibacterial efficiency reached 99%,which could maintain the antifouling ability of the real sea for a long time.3.Taking double ended hydroxypropyl polydimethylsiloxane(PDMS)and polytetrahydrofuran(PTMG)as main materials,2-hydroxyethyl disulfide(HEDS)and dimethylglyoxime(DMG)as chain extenders,copper chloride(Cu Cl₂)as coordination metal and silver nanoparticles(Ag NPs)as antibacterial filler,an Ag NPs/silicone oxime urethane self repairing antifouling coating(Ag NPs-X%/PDMS-DOU)which can be used in the field of marine antifouling was prepared.The material has good mechanical properties,and the tensile stress can reach 2.75 MPa.Based on the interaction of disulfide bond,oxime urethane bond,metal coordination bond and hydrogen bond,and Cu²⁺could also promote the dissociation of oxime urethane bond,the material can realize self repair at room temperature,and the healing efficiency could reach 91.7%.EDS proved the uniform dispersion of Ag NPs filler.Because Ag NPs have excellent antibacterial activity,the resistance to marine bacteria Pseudomonas reached 97.8%,which has great application potential in the field of marine antifouling.