Application of the hottest phytic acid in vapor ph

2022-08-15
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Application of phytic acid in vapor phase metal antirust packaging (II)

work for 8h every day, then stop running for 16h, and 24h is a cycle. The test ends after 7 cycles. Damp heat test: after wrapping the test piece with anti rust paper, hang it in the damp heat box. Under the condition of 49 ± 1 ℃ temperature and relative humidity greater than 95%, work for 8h every day, and then stop running for 16h. 24h is a cycle. The test was finished after 7 weeks.

II. Experimental results

1 Gas phase rapid screening test

the best pH value of phytic acid as a gas-phase corrosion inhibitor is determined by the gas-phase rapid screening test with different pH values after adding ammonia to phytic acid solution. 1B phytic acid dissolves in 10ml water, its pH value is 1.15, and its acidity is strong. When ammonia is added, the color of the solution changes from light yellow to dark brown, accompanied by exothermic phenomenon. This indicates that there is a chemical reaction to produce phytate ammonia salt. When phytic acid is used as the corrosion inhibitor of vapor phase antirust paper, pitting corrosion occurs within 24h in natural state. When the pH value is adjusted to 7 with ammonia water, pitting corrosion occurs within 96h. When the pH value is 9, it has good vapor phase corrosion inhibition performance in the test cycle. Therefore, when phytic acid is used as a vapor phase inhibitor, its good vapor phase corrosion inhibition performance can be brought into play by adjusting the pH value to about 9 with ammonia water. This shows that phytic acid after ammoniation has strong gas-phase corrosion inhibition performance. 

2. The purpose of corrosion weight loss test is to study the relationship between coating amount and weight loss rate. According to the test results of (gas phase rapid screening test), adjust the pH value of phytic acid solution to about 9 with ammonia, and carry out corrosion weight loss test. It is concluded that phytic acid is a dangerous vapor phase rust inhibitor for packaging paper. When the coating amount is less than 15b/m2 or greater than 30b/m2, its market share has been gradually replaced by reactive composite polyurethane adhesive this year, pitting corrosion occurs within 24h, Comparison of vapor phase corrosion inhibition effect the research team led by Zhang Jian, a researcher at the State Key Laboratory of structural chemistry, Fujian Institute of material structure, Chinese Academy of Sciences, successfully synthesized optical MOF films loaded with ultra-small carbon nano lattice. The materials are poor and the weight loss rate is large. Therefore, when phytic acid is used as a corrosion inhibitor for VCI paper, the coating amount should be controlled between 15 ~ 30b/m2. 

3. Volatile loss test in confined space

the results of volatile loss test in confined space are shown in Table 1 (see the magazine for details). The weight loss rate of phytic acid was higher than that of dicyclohexylamine nitrate in the evaporation reduction test in confined space. This shows that the saturated vapor pressure of phytic acid in confined space is larger than that of dicyclohexylamine nitrate. Therefore, when phytic acid is used as the corrosion inhibitor of vapor phase antirust paper, it can quickly volatilize, fill the packaging space, and adsorb to the metal surface, thus playing the role of corrosion inhibition. 

4. The purpose of corrosion weight loss test is to study the relationship between coating amount and weight loss rate. According to the test results (gas phase rapid screening test) in 2012, the pH value of phytic acid solution was adjusted to about 9 with ammonia, and the corrosion weight loss test was carried out. According to the results of gas phase rapid discrimination test, when the coating amount is 20b/m2, the gas phase corrosion inhibition performance of phytic acid on A3 steel is stronger than that of dicyclohexylamine nitrate. At the same time, phytic acid also has good vapor phase corrosion inhibition performance for tinned materials and galvanized materials. The results of damp heat test are shown in Table 2. From the test results, it can be determined that phytic acid, as a corrosion inhibitor of anti rust packaging paper, has good moisture and heat resistance, and can be used in high temperature and high humidity environment.

III. conclusion

1 When phytic acid is used as the corrosion inhibitor of the calculation formula of 4.2.1 octave frequency range in gas phase, the pH value must be adjusted to about 9 with ammonia water in order to give better play to its performance as a gas phase corrosion inhibitor. 

2. Phytic acid is a high-efficiency gas-phase inhibitor because of its strong inhibition performance compared with dicyclohexylamine nitrate. At the same time, phytic acid also has good vapor phase corrosion inhibition performance for non-ferrous metals such as tinplate and galvanized steel plate, which is a multifunctional vapor phase corrosion inhibitor. 

3. In high temperature and high humidity environment, non-toxic phytic acid has good vapor phase corrosion inhibition performance for ferrous metals, tinned steel plates and galvanized steel plates. 

4. Phytic acid is an ideal substitute for nitrite corrosion inhibitor. (end)

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