Preparation And Rust Resistance Performance Study Of Blending Particles Of Polymer/Corrsion Inhibitor

In the coastal environment, reinforced concrete structures are damaged badly by a large number of chlorides, which has a negative influence on the durability and safety of reinforced concrete.Steel corrosion inhibitors have an outstanding effect in inhibiting corrosion of reinforced concrete, but most of them have some disadvantages, such as high water solubility, easy-tolost, low efficiency and short duration of action, etc. In recent years, some researchers use microcapsule techniques to encapsulate steel corrosion inhibitors in order to delay the releasing time of inhibitors, but the preparation technology is complex and expensive.In this paper, melting extrusion technique was used to prepare corrosion inhibitor. Three kinds of steel corrosion inhibitors, calcium nitrate, fluoride sodium phosphate and calcium hydroxide were encapsulated by two different polymer materials, respectively. Polymer/ steel corrosion inhibitors blending particles have some advantages of simple processing, high efficiency, low cost, easy to replace matrix materials, adjustable release rate of steel corrosion inhibitor and high encapsulation efficiency, etc. The three polymer/steel corrosion inhibitors blending particles are investigated as follows in the paper.Ion chromatography was used to measure the release rate of calcium nitrite of polymer/calcium nitrite blending particles in simulated concrete solution. The results show that the releaseing rate of PS/Ca?NO2?₂ blending particles is faster than LDPE/Ca?NO2?₂ blending particles. Potentiodynamic method and EIS were used in a simulated concrete pore solution to make a tafel fitting, EIS equivalent circuit?model R1?Q1?R2?Q2R3??? and R1?Q1R2?? fitting and analyze the macrocorrosion of the fracture surface of the steel. It indicates the corrosion current density of 4% weight of PS/20% Ca?NO2?₂ blending particles and 5% weight of LDPE/20%Ca?NO2?₂ blending particles are three orders lower than that of the control group and one order lower than that of the single-doped calcium nitrite. The capacitive loop is larger than that of the single-doped calcium nitrite, which shows that polymer/ calcium nitrite blends exhibite good corrosion inhibition effect. The adding of polymer/the calcium nitrate blending particles into concrete can increase the corrosion potential, reduce the corrosion current density and corrosion rate. It indicated that polymer/calcium nitrate blends have a good rust resistance effect. SEM results indicated that there was a big gap between blending particles and concrete. The smaller blending particles had better combination with concrete.For polymer/MFP blending particles, TG was used to test the remaining amount of MFP with soaking time,Which can measure the releasing rate of MFP. The results show that the release rate of PS/MFP blending particles is higher than that of LDPE/MFP blending particles. Potentiodynamic and EIS test in simulated concrete pore solution show that polymer/MFP blending particles can reduce the current density of steel corrosion. And with the increase of the content, the long-term effect is more obvious. The results of EIS measurements show that the Impedance Spectroscopy of simulated solution contains two time constants, which are from the impedance of solution and the passivation film of steel surface, respectively. With the increase of the content of the blending particles, capacitive arc radius is increased and inhibiting effectiveness is enhanced. In the concrete, polymer/MFP blending particles can also reduce the corrosion current density of steel and increase the steel capacitive arc radius. Thus, polymer/MFP blending particles have a certain rust effect.For polymer/Ca?OH?₂ blending particles, TG results show that the releasing rate of PS/Ca?OH?₂ blends is higher than that of LDPE/Ca?OH?₂ blends. Polymer/Ca?OH?₂ blends could increase the pH value of simulated concrete solution in some extent. Polymer/Ca?OH?₂ blending particles have little effect on corrosion current density of steel, but the EIS capacitive arc radius results show that the adding of polymer/Ca?OH?₂ blends can increase capacitive arc radius. It indicated that polymer/Ca?OH?₂ blending particles had a certain inhibition effect to steel.