Research Of Antibacterial And Low Surface Energy Composite Marine Antifouling Coatings

The issue of marine fouling and protection has been classified as a worldwide technical problem due to the intersection of several disciplines such as materials,chemistry,and biology,and has been also widely concerned by domestic and foreign research scholars.Marine equipment plays an extremely important role in the development of marine resources,and the complexity of the marine environment has put forward higher and higher requirements for its surface protection.Among the existing antifouling technologies,antifouling coatings are the most widely used marine fouling protection technology.Among them,low surface energy antifouling coatings(fouling release type,FRC)have become the focus of relevant research due to their green,non-toxic,and environmentally friendly characteristics.In recent years,low surface energy silicone antifouling coatings have been developed rapidly,but the shortcoming of the static antifouling ability and the unsatisfying mechanical properties limited their further application.Therefore,there is an urgent need to carry out relevant research work.Adopting antibacterial modification strategies and developing antibacterial low surface energy composite marine antifouling coatings can significantly improve the antifouling ability of coatings in the early stages of marine fouling and static seawater,which is expected to fundamentally improve the comprehensive performance of the organic silicon low surface energy antifouling coatings.In this paper,to meet the technical needs of performance improvement of low surface energy silicone antifouling coatings,two different antimicrobial agent introduction methods were used to prepare two kinds of antimicrobial compounding modified silicone/polyurethane marine antifouling coatings,based on the idea of antimicrobial modification and functional compounding of coatings.The comprehensive performances of the developed antifouling coatings were tested and evaluated by laboratory macro and micro technical means and marine environment test.The specific research contents and results are as follows:1.A series of organosilicon/polyurethane copolymer low surface energy antifouling coatings(PDMS/PU)with different formulations were prepared from isophorone diisocyanate(IPDI),polypropylene glycol(PPG),and hydroxy silicone oil(PDMS).The chemical composition of the copolymer was verified by Fourier transform infrared spectroscopy.The static water contact angles,adhesion,impact resistance,and flexibility of the modified low surface energy coatings were tested and studied in detail.It was found that the mechanical properties of the modified coatings have been significantly improved.When the molar ratio of PDMS and PPG was 1:2,the static water contact angle was up to114.04°,the adhesion was 2.670 MPa,the forward impact resistance height was up to 70 cm,the reverse impact resistance height was up to 65 cm,and the flexibility test result was 1 mm,which was used as the base formulation for the subsequent study.2.A series of additive antibacterial low surface energy composite marine antifouling coatings with different CTAB contents were prepared by introducing the organic antibacterial agent cetyltrimethylammonium bromide(CTAB)into PDMS/PU coatings by direct addition.It was found that when the mass fraction of CTAB was 6% or less,it dispersed well in the coating without obvious agglomeration through the SEM test.The static water contact angles,mechanical properties,and antibacterial properties of the coatings were tested and studied in detail.It was found that when the mass fraction of CTAB in the coatings was 6%,the static water contact angle of the coating was 103.12°,the adhesion was 2.780 MPa,the forward impact resistance height was 65 cm,the reverse impact resistance height was 60 cm,and the flexibility was 1 mm.At the same time,the antibacterial rate against S.aureus reached 100%,and the antibacterial rate against E.coli reached 98.97%.Also,the test results of the marine environmental test showed that the coating has excellent antifouling performance.3.Dihydroxy quaternary ammonium salt(QAS)was prepared with hexadecyl dimethyl tertiary amine(DMA16)and epichlorohydrin.A series of structural antibacterial low surface energy composite marine antifouling coatings with different QAS contents were prepared through chain segment structure compounding.The chemical composition was verified by Fourier transform infrared spectroscopy.The static water contact angles,mechanical properties,and antibacterial properties of the coatings were tested,and the results showed that when the mass fraction of QAS in the coatings was 8.45%,the static water contact angle of the coating was 102.23°,the adhesion was 2.75 MPa,the forward impact resistance height was 75 cm,the reverse impact resistance height was 70 cm,and the flexibility was 1 mm.At the same time,the antibacterial rate against S.aureus reached 100%,and the antibacterial rate against E.coli reached 99.23%.Meanwhile,the test results of the marine environmental test showed that the coating has excellent antifouling performance.4.A comparative analysis was conducted on the comprehensive performance of the additive and structural antibacterial composite modified coatings,and the results showed that the performance of structural composite coatings was more excellent.However,considering the relatively low process difficulty,and the feasibility of implementation of additive composite coatings,they can be used as the current coating technology solution.From the long-term development point of view,structural composite coatings can better meet the technical needs of future equipment marine fouling protection.