Preparation And Properties Of Polymer-sulphoaluminate Cement Based Anticorrosive Coating

Concrete is an irreplaceable key material for marine engineering construction,but the harsh marine environment can easily cause performance deterioration and structure failure of concrete,which has a bad impact on the safety and service life of marine engineering.Coating protection is one of the simple and effective ways to improve the durability of concrete.The research on high performance coating is of great significance.Polymer cement based coating as a potential anti-corrosion material,it has the advantages of good durability of cement material and high elasticity and toughness of polymer,also good compatibility with concrete.However,in the face of the harsh marine environment,the service performance of traditional polymer cement based coating is still unsatisfactory,and it is urgent to be innovatively designed from the composition and structure to clarify its structure-activity relationship.In this paper,silicone modified polyacrylate emulsion?SPA?and sulphoaluminate cement?SAC?are used as main components to prepare polymer cement based coating with excellent corrosion resistance and weather resistance.Firstly,the preparation of SPA and its regulation of compatibility with SAC are investigated.Next,the composition design of polymer-sulphoaluminate cement based coating is studied.On this basis,the anti-corrosion performance is further strengthened by polypropylene fiber?PPF?and graphene oxide?GO?.Finally,the application properties of polymer sulphoaluminate cement based coating and conventional anti-corrosion coatings on concrete surface are analyzed.The main results are as follows:?1?A suitable ratio of soft to hard monomer can effectively reduce film forming temperature of SPA.Proper anionic to nonionic emulsifier ratio and acrylic monomer content can effectively improve the compatibility of SPA with SAC.When the ratio of soft to hard monomer is 60:40,the dosage of initiator is 0.4%,the dosage of emulsifiers is 4%,the radio of SDS to OP-10 is 2:3,dosage of acrylic monomer is 2%,the dosage of silicone monomer is2%,emulsion performance is optimal,and compatibility of SPA with SAC is the best.?2?The optimal composition of the coating is obtained based on the response surface methodology,are 0.8-1.0 for SAC/SPA,0.10 to 0.11 for redispersible emulate powder?REP?/SPA and 1.1-1.3 for SiO₂/SPA.When the ratio of polymer?the radio of REP to SPA is0.1?to SAC is 1.0,and the amount of antifoaming agent and film forming additive is 0.28%and 3%,respectively,the overall performance of the coating is optimal.?3?PPF can effectively improve physical properties,UV aging resistance and Cl^-penetration resistance of coating,because it can increase the packing density and reduce the porosity coating.When the dosage of PPF is 0.3%,the density of coating is optimal,the packing density is increased by 3.08%compared with the blank,and the porosity is reduced by 12.5%;The bond strength and tensile strength reach the maximum of 3.79 MPa and 3.82MPa,which increased by 10.68%and 62.59%compared with the blank respectively;After UV accelerated aging for 1000h,the loss rate of tensile strength and elongation at break reach the minimum of 3.39%and 48.51%,which is 14.94%and 8.04%lower than the blank,respectively;SEM and FTIR analysis show that the coating containing PPF has a better polymer film structure after UV accelerated aging;The electric flux at 6h is reduced by 48.92%compared with the blank sample.?4?GO can effectively improve physical properties,anti-ultraviolet ageing performance and Cl^-penetration resistance of coating.When the dosage of GO is 0.05%,the working performance of coating is optimal,and the thixotropy is increased by 210.39%compared with the blank;The bond strength and tensile strength reach the maximum of 4.21MPa and3.01MPa,which increased by 22.93%and 27.92%compared with the blank respectively;After UV accelerated aging for 1000h,the loss rate of tensile strength and elongation at break reach the minimum of 6.78%and 33.55%,which is 27.92%and 22.93%lower than the blank,respectively;SEM analysis shows that coating containing GO has a better polymer film structure after UV accelerated aging;FTIR analysis shows that GO can attenuate polymer degradation caused by ultraviolet accelerated aging;The electric flux at 6h is reduced by51.91%compared with the blank sample.?5?A high performance polymer sulphoaluminate cement coating?PG coating?is prepared with 0.3%PPF and 0.05%GO.Compared to commercial polymer cement based coatings and organic coatings,PG coatings have the best protection against concrete through experiments such as alkali resistance,Cl^-penetration resistance,temperature resistance and impermeability.