Preparation And Marine Antifouling Performance Of SBMA Modified Polydimethylsiloxane Random Copolymer

Marine biological fouling has a serious impact on human Marine production and transportation activities,directly or indirectly causing huge economic losses,ecological losses and environmental losses.Traditional Marine antifouling coatings are prohibited because they contain heavy metal toxic antifouling agents that will destroy Marine ecological environment.Antifouling coatings with low surface energy based on polydimethylsiloxane（PDMS）have been used commercially and have good prospects for development.However,this material has low mechanical strength,static anti-fouling performance is not ideal and other problems,reduce the use of anti-fouling coating effect.In this paper,dimethylaminoethyl methacrylate（DMAEMA）and vinyl-dimethylsiloxane were used as monomers to synthesize copolymers with different proportions（Dmaema-PDMs）through random copolymerization.Then,the copolymer of DMAEMA-PDMS was modified by using 1,3-propyl sulfonolactone through quaternization reaction.The amphozwitterion sulfobetaine methacrylate（SBMA）side chain was introduced,and the acrylic acid modification and the amphozwitterion functional side chain were used to obtain the polydimethylsiloxane modified polymer with good mechanical properties and static antifouling properties.Due to the poor compatibility of SBMA and PDMS,the yield of atom transfer radical polymerization is low.The amphoteric copolymer（SBMA-PDMS）was prepared by two-step random copolymerization to obtain high yield amphoteric copolymer.Due to the poor compatibility of SBMA and PDMS,zwitterion copolymers（SBMA-PDMS）were prepared by a two-step method.Firstly,the feasibility of the reaction between DMAEMA,a precursor of SBMA,and PDMS was verified,and the appropriate reaction conditions of DMAEMA-PDMS copolymer were investigated.The solubility,yield,and water absorption of three different PDMS（self-made high-activity vinyl polydimethylsiloxane,vinyl-terminated polydimethylsiloxane,and divinyl-tetramethyl-disiloxane）copolymers obtained by reacting with DMAEMA were compared,determining that vinyl-terminated polydimethylsiloxane was the PDMS monomer for the reaction.By measuring the disappearance time of reactive groups in the copolymerization of PDMS and DMAEMA at different reaction times,the reaction time was determined to be 40 h.The yield and molecular weight of the copolymer in the control group were compared to determine other reaction conditions:methylene chloride/methanol reaction solvent,initiator content（total weight of monomer 0.5‰）,and continuous N₂ atmosphere to protect the environment.Theeffect of modification of amphoteric copolymer on antifouling performance of PDMS was studied.The surface morphology and roughness of DMAEMA-PDMS copolymer film at different concentrations were observed by laser confocal microscope.It can be seen that the surface of the copolymer film is relatively smooth and has certain roughness.The water contact angle test showed that the surface contact angle of copolymer film can reach 120°,and the whole film was hydrophobic.The mechanical property test results showed that the average tensile strength of DMAEMA-PDMS copolymer is up to 24.98 MPa,which had strong tensile resistance.The anti-diatom attachment experiments displayed that the copolymer film of DMAEMA-PDMS had the highest inhibition rates of 87.3%and 74%against Navicula exigua and Phaeodactylum tricorniformis,which showed strong antifouling performance.The zwitterion copolymer SBMA-PDMS was obtained by quaternization.Due to the poor solubility of SBMA-PDMS,different proportions of SBMA-PDMS were added to silicone coatings as antifouling agents to form coatings.Using a three-dimensional microscope to observe the surface morphology of the modified silicone coating,it was found that white amphoteric copolymer oozes exude onto the surface of the coating,filling the defects of the silicone coating and reducing the surface roughness.The roughness of the modified silicone coatings decreased by 77.2%at most.The results of water absorption showed that the water absorption rate of the modified coating is not high,which has little influence on the surface properties of the coatings.The water contact angle was tested on the surface of the coatings,and it was found that the contact angle was reduced to 99.8°,which enhanced the hydrophilicity of the coatings.The results showed that the modified coatings have inhibition rates of80.7%and 88.6%against Navicula exigua and Phaeodactylum tricorniformis,respectively.The anti-protein adsorption test was conducted on the modified coatings,and the results displayed that the coating exhibited excellent anti-protein adsorption capabilities.The antibacterial test showed that the modified coatings had good antibacterial effects.The results from the anti-diatom adhesion test showed that there are few fouling organisms attached to the modified coating surface.The actual sea hanging plate results showed that the attachment of barnacles to the modified coatings decreased,demonstrating that the zwitterionic polymer can improve the antifouling performance of the coatings by forming a"hydration layer".The results of antifouling performance test showed that the higher the content of SBMA in zwitterion copolymer,the better the antifouling performance of the coatings.The above research indicated that the modification of acrylic acid and the introduction of zwitterionic groups in side chains can improve the mechanical properties and static antifouling properties of the organosilicon matrix resin.This provides a technical scheme to improve the performance of silicone antifouling materials with low surface energy.