The Preparation Of Graphene Oxide/Acrylic Resin Coating And Its Protective Effect On Concrete

The aggressive ions in the environment and bio-fouling are the important factors,leading to durability damage for reinforced concrete strucutres.Concrete surface coating is considered as an effective and simple method to improve the durability of concrete,because it can efficiently prevent the transport of aggressive ions and bio-fouling.However,in present,the commonly used concrete surface coating still presents several disadvantages,e.g.single anti-corrosion performance,easy aging,short service life,and less consideration for bio-erosion factors.In addition,the antifouling coatings are normally used in the antifouling for marine vessels,most of which are toxic and antifouling materials,and environmentally friendly low surface energy antifouling coatings have problems such as poor mechanical properties.Graphene oxide is a type of nano materials,which can significantly improve the adhesion,wear resistance and anticorrosion properties of the surface coating.However,the uniform distribution of graphene oxide in polymers is very difficult.In this paper,a series of low surface energy acrylic resin with satisfied basic mechanical properties were designed and prepared to solve the above problems,and the effects of the type and amount of functional monomers on the properties of the resin were discussed.On this basis,modified graphene oxide(FGO)grafted with vinyltriethoxysilane(A151)was incorporated into the low surface energy acrylic resin to prepare graphene oxide/low surface energy acrylic resin composite coatings with excellent corrosion resistance.The protective effect of the coating on concrete was investigated.The detail research contents and achievements of this paper are summarized as follows:(1)Silicon modified,fluorine modified and silicon/fluorine modified low surface energy resins were designed and prepared by using methyl methacrylate(MMA),butyl acrylate(BA),dodecafluoroheptyl methacrylate(FMA)andγ-(methacryloxypropyl)trimethoxysilane(KH570)monomers.The research results indicated that the chemical structure of the copolymer was in accordance with the expected results and the monomer conversion rate was high.Fluorine modified and silicon/fluoride modified acrylic resin presented low surface energy,and the lowest surface energy was 23.3 mJ/m~2;the fluorine modified and silicon/fluoride modified acrylic resins presented very high bacteriostatic rate of up to 99.9%,good chemical erosion resistance and low water absorption.The silicon modified resin and silicon/fluoride modified resin presented good adhesion to cement paste,and the highest adhesion level was 5A.(2)Graphene oxide(GO)was prepared by modified Hummers method and modified graphene oxide(FGO)was prepared by grafting A151 coupling agent onto graphene oxide with hydroxyl groups on the surface of GO.GO and FGO were then dispersed in acrylate monomers to prepare the graphene oxide/low surface energy acrylic resin composite coating by in-situ polymerization.The results showed that GO and FGO effectively enhanced the toughness and seawater erosion resistance of the coating;the dispersion of FGO in the resin was better than GO;the optimum dosage of FGO was 0.15%,and the chloride ion penetration amount of FGO acrylic coating was 2.4 mg/L after 90 days.(3)The ultraviolet aging resistance of the modified graphene oxide/low surface energy acrylic resin coating and its protective effect on concrete under different erosion conditions(antibacterial property,seawater erosion,organic acid erosion)were investigated.The results showed that the aging rate of the modified graphene oxide/low surface energy acrylic resin coating was 6.1%after 1000 h UV aging,lower the epoxy coating(95.4%)and asphalt coating(34.1%).The anti-coliform rate of the modified graphene oxide/low surface energy acrylic resin coating was 99.9%;after 28 days of mold test,there was no growth of mold on the surface.After 90 days of seawater erosion,the chloride ion content at the specimen surface 0-0.5 cm was 49.93 mg/L,which was slightly higher than epoxy glass scale coating(45.13 mg/L).After immersion in organic acid solution for 30 days,the surface of the coating was intact and the degradation rate was 10.3%,which was much lower than other two types of coatings(64.3%for epoxy coating and 100.0%for asphalt coating).