Preparation And Evaluation Of Environmentally Friendly Vapor Phase Anti Rust Film For Carbon Steel

The application of vapor phase rust prevention in modern industry is becoming increasingly widespread,and the development of vapor phase rust prevention packaging materials is one of the key factors.Vapor phase anti rust film has good gas resistance,transparency,processability,and environmental adaptability,which is the focus of research on vapor phase anti rust packaging materials.At present,the formulation of rust inhibitors in vapor phase rust prevention films in commercial applications is mainly composed of amines,nitrites,etc.,which have high toxicity and increasingly prominent environmental impacts.In recent years,with the improvement of environmental protection requirements,the development of low toxicity and efficient vapor phase rust prevention products has become a research hotspot and difficulty.Developing environmentally friendly and efficient vapor phase rust prevention films has important engineering value.This topic focuses on the vapor phase rust prevention packaging of carbon steel.Firstly,the volatilization and corrosion inhibition performance of single component sodium benzoate,n-octanoic acid,and ammonium molybdate are studied;Secondly,a highly efficient composite vapor phase corrosion inhibitor formula was obtained through orthogonal experiments.And the corrosion inhibition performance and mechanism of composite vapor phase corrosion inhibitors were measured and analyzed using electrochemical,contact angle,XPS and other methods;Finally,a composite vapor phase corrosion inhibitor was combined with LDPE resin to prepare a vapor phase anti rust film,and the effect of the amount of vapor phase corrosion inhibitor added on the related properties of the film was analyzed.The main research conclusions are as follows:（1）Compounding environmentally friendly vapor phase corrosion inhibitors for carbon steel.Among the three vapor phase corrosion inhibitors,sodium benzoate,n-octanoic acid,and ammonium molybdate,n-octanoic acid has the best volatilization performance,with a weight loss rate of 13.55%and the highest corrosion inhibition efficiency,at 91.35%.When sodium benzoate and ammonium molybdate are used alone,their corrosion inhibition efficiency for carbon steel is not significant,reaching 20.54%and 11.35%,respectively.When the two are combined,the synergistic effect of corrosion inhibition is significant,and the corrosion inhibition efficiency increases to 67.57%.The optimal ratio of sodium benzoate,n-octanoic acid,and ammonium molybdate was 3:1:1 through a three factor and three level orthogonal experiment,achieving a corrosion inhibition efficiency of 96.22%for carbon steel.Electrochemical tests have shown that composite vapor phase corrosion inhibitors have a good inhibitory effect on the anodic dissolution reaction of metal corrosion.With the increase of inhibitor concentration,the corrosion current density decreases,the charge transfer resistance increases,and the corrosion inhibition performance also improves.（2）Research on the corrosion inhibition performance and mechanism of composite vapor phase corrosion inhibitors.Electrochemical experiments have shown that during the temperature increase from 298 K to 348 K,the corrosion current density of carbon steel increases from 4.8μA·cm^-2 increases to 22.32μA·cm^-2,the charge transfer resistance decreased from 9657Ω·cm^-2 to 1800Ω·cm^-2,indicating a gradual decrease in the corrosion inhibition performance of vapor phase inhibitors on carbon steel;UV spectroscopy,contact angle,and XPS analysis revealed that there was an interaction betweenπ-electrons and metal vacancy d orbitals in the composite vapor phase corrosion inhibitor;The composite vapor phase corrosion inhibitor adsorbs on the surface of carbon steel to form a corrosion inhibition film,which increases the contact angle between the metal and water vapor,thereby improving its water repellency;At the same time,after leaving the gas phase inhibitor atmosphere,the corrosion inhibitor film still has a certain degree of corrosion inhibition performance on carbon steel,but the corrosion inhibition effect is not significant.The adsorption of composite vapor phase corrosion inhibitors on the surface of carbon steel follows the Langmuir adsorption model and can spontaneously and physically adsorb on the surface of carbon steel.（3）Preparation of vapor phase anti rust film.Mix the composite vapor phase corrosion inhibitor with LDPE resin in the proportions of 1.0%,1.5%,2.0%,and 2.5%,and prepare a vapor phase anti rust film by extrusion blow molding.Measure and analyze the film performance.The results showed that with the increase of the content of vapor phase corrosion inhibitor,the transparency,barrier,and mechanical properties of the vapor phase rust prevention film decreased;The content of vapor phase corrosion inhibitor is greater than 1.5%of the packaging film,and the 9 cycles of alternating damp heat test carbon steel samples have no rust,meeting the requirements of GB/T19532-2018"Packaging Materials-Vapor Phase Anti rust Plastic Film".