Preparation And Properties Of Polyurethane Modified Organosilicon Antifouling Coatings

Fouling release antifouling coating is a safe and harmless antifouling coating that can achieve a good antifouling effect without toxic bactericides,and silicone antifouling coating is the most representative one.However,the mechanical properties of silicone are poor,and the adhesion between the silicone and the substrate is also defective.In this regard,this thesis adopts the method of polyurethane modification to make up.However,due to the poor compatibility between the soft and hard segments of polyurethane,there is microphase separation in the polyurethane,which will affect the performance of the modified coating.Aiming at this problem,this thesis mainly conducts the following research:(1)Polyether diol HSH220(PED),2,4-toluene diisocyanate(TDI),hydroxypropylterminated polydimethylsiloxane(PDMS2200)were used to prepare polyurethane,and the modified silicone coating was prepared in the ratio of silicone resin(DY-107): polyurethane:ethyl orthosilicate: catalyst = 20:5:4:1.A series of polyurethane modified silicone coatings were prepared by adjusting the ratio of catalyst.The surface drying time and surface roughness of these coatings were compared.It was found that when the ratio of catalyst was 0.5,the modified coatings could reach the surface dry within 20-30 minutes and have good surface morphology.Then,three different modified coatings were prepared by adjusting the ratio between silicone and polyurethane,and their surface and interface properties,tensile properties,and antifouling properties were tested.It was found that when silicone: polyurethane =20:5,the modified coating has the highest breaking strength and elongation,and its antifouling effect is the best.To sum up,the ratio of silicone: polyurethane: ethyl orthosilicate: catalyst = 20:5:4:0.5 was selected to prepare the modified silicone coatings.(2)PED and polyethylene glycol 2000(PEG2000)were selected as the raw materials of soft segment,and TDI and isophorone diisocyanate(IPDI)were selected as the raw materials of hard segment to prepare PED-TDI polyurethanes,PED-IPDI polyurethanes,and PEG-IPDI polyurethanes.And different content of PDMS2200 was introduced into the polyurethane segment by the method of copolymerization.These polyurethanes were used as one of the filmforming materials to carry out a blending reaction with silicone,and a series of modified coatings were obtained after cross-linking and curing.ATR-FTIR,NMR,CLSM,AFM,contact angle measurement,tensile test,bacterial adhesion,and benthic diatom adhesion test were used to investigate the structure,morphology,roughness,degree of microphase separation,surface energy,tensile properties,and antifouling properties of the modified coatings.The results show that TDI can reduce the surface roughness of the coating,IPDI can provide lower surface energy and elastic modulus,and PED can reduce the roughness and surface energy of the coating;and increasing the content of PDMS2200 in the soft segment can increase the degree of microphase separation of the polyurethane,so that more silicone segments could enrich on the surface,thus reducing the roughness,surface energy and elastic modulus of the coating.Its antifouling performance has also been improved.When PED-IPDI polyurethane was used to modify the silicon,and the molar percentage of PDMS2200 accounted for 17% of the soft segment raw material,the surface energy of the modified coating was the lowest,and its mechanical properties and antifouling properties were also the best.