| Marine biofouling is a challenge that needs to be faced in the current exploitation of marine resources.Currently,the application of marine antifouling coatings is the most cost-effective means of preventing and controlling marine biofouling.Self polishing coatings and fouling release coatings have been extensively studied in antifouling coatings.However,the anti-fouling effect of self-polishing coatings comes from anti-fouling agents,which have a greater impact on the environment;fouling-release coatings have poor static anti-fouling capacity,low mechanical properties and are highly susceptible to damage.With the release of policies requiring clean ship bottom entry in major ports,the development of coatings that combine anti-fouling properties with abrasion resistance has become a new trend.In this paper,polyaspartic ester polyurea with good mechanical properties was used as a research object.Three antifouling active substances were chemically grafted into polyaspartic ester polyurea resin by antifouling agent immobilization strategy.Antifouling functional group modified polyaspartic ester polyurea coating was prepared.The surface properties,mechanical properties and abrasion resistance of the modified polyurea coating were investigated,and the anti-fouling properties of the coatings were evaluated using anti diatom adhesion and anti mussel settlement experiments.The coupling agent modified pyrimidine(pd-560)was prepared by amino-epoxy ring opening reaction using silane coupling agent KH560 and 2,4,6-triaminopyrimidine,and the isocyanate-based capped prepolymer was prepared using polyether polyol and isophorone diisocyanate(IPDI)as raw materials.Pyrimidine-modified polyaspartic ester polyurea(AMPU-x)obtained after curing reaction of prepolymer,pd-560 and polyaspartic ester NH1220.The contact angle test and surface morphology of AMPU-x were observed,and it was found that the introduction of modified pyrimidine made the coating surface rougher,while the contact angle showed a decreasing trend due to the increase of hydrophilic hydroxyl content.The mechanical property tests revealed that the addition of modified pyrimidine could improve the hardness and adhesion of the coating,and the moderate amount of addition would also enhance its tensile strength,but a large amount of addition would affect the internal crystallinity of the polymer and reduce the tensile strength of the coating.Through the abrasion test,it was found that the wear amount of the coating decreased first and then increased,and the minimum wear amount was 0.0481 g.The surface roughness and the degree of cross-linking together affected its wear resistance.The antifouling performance of the coating was evaluated by the anti-diatom adhesion experiment,and the introduction of pyrimidine led to a significant increase in the antifouling performance of the polyurea coating,which AMPU2.5 had the best performance.The inhibited adhesion ratio of Halamphora sp.and N.Closterium reached 93.71% and 90.25% respectively,but the anti-diatom adhesion ratio of the coating showed a decreasing trend as the amount of pyrimidine increased.The antifouling active substance 2-mercaptobenzothiazole(MBTS)was prepared by using disulfide-mercapto exchange reaction with dibenzothiazole and β-mercaptoethanol,and its isocyanate was functionalized by IPDI.It was grafted into polyether prepolymer and cured by polyaspartate NH1220 to obtain benzothiazole-modified polyaspartate polyurea MTGPU-x,and added to MBTS in the form of physical doping to obtain the contrast coating MTBPU-x.The grafting of monofunctional antifouling agents led to a weakening of the thermal stability and mechanical strength of the coating,but its surface wettability did not change much.Abrasion resistance experiments showed that the introduction of MBTS increased the rigid part of the polymer,and the abrasion resistance tended to increase with the increase of the introduced amount.The grafting of MBTS enabled the polyurea coating to obtain excellent antifouling properties,which gradually increased with the amount of grafting.The anti-settlement ratio of MTGPU9.5 for Halamphora sp.and N.Closterium reached 98.34%and 96.35% respectively.The anti-mussel attachment test showed that the MTGPU-x coatings had an inhibitory effect on mussel settlement,and the number of foot filaments on the surface of MTGPU9.5 was reduced by 73.24% compared with glass flakes.1,2-Benzisothiazol-3-one(BIT)was grafted into the amino silicone oil chain segment by the reaction of isocyanate group and active hydrogen and prepared into isocyanate-based capped silicone prepolymer(PPCB)containing BIT,and then compounded with different amounts of polyether polyol prepolymer and cured with polyaspartate NH1220 to obtain BIT-amino silicone oil modified polyaspartate polyurea coating(STPU-x).Surface morphology and wettability tests of the modified coatings revealed an increase in hydrophobicity and a decrease in surface energy of the coatings.The addition of silicone chain segments resulted in a decrease in the mechanical properties of the coating,and the tensile strength and adhesion were weakened.The abrasion resistance test found that the introduction of PPCB made the surface of the coating smoother and the abrasion resistance was improved,but the addition of large amount made the surface roughness of the coating increase and the abrasion amount of the coating increased.The antifouling test found that STPU20 had the best antifouling performance,The anti-settlement ratio of STPU20 for Halamphora sp.and N.Closterium reached 95.05% and 98.47% respectively.while their adhesion inhibition was also effective for large fouling organisms,and the number of pedicels on coating’s surface was reduced by 77% compared with glass flakes. |
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