The development of single-group watery epoxy polyphenylamine anticorrosive primer

China Coatings Network
News: In 1991, the Los Alamos National Laboratory (LANL) and NASA joint research team successfully applied conductive polymers to steel corrosion protection for the first time, obtained excellent anti-corrosion effect, and confirmed that doped polyphenyl coating on the coating scratching anti-corrosion, the synthesis of polyphenylamine with anti-corrosion properties became a hot topic of concern. Metal corrosion: usually refers to the phenomenon of damage caused by the physical, chemical or electrochemical effects of metals and environmental media. Metal corrosion phenomenon and harm widely exist in daily life and industrial production, the direct economic loss caused by corrosion is quite huge. According to the comprehensive metal erosion survey report of the United States and Britain, the economic losses caused by corrosion account for 3.5% of GDP in the United States and 4.2% in the United Kingdom each year. According to data estimates, every year worldwide due to corrosion can not be used normal metal material equipment and facilities, about equal to the world's total production of metal materials in that year 20% to 40%, and a small part of the corroded metal material, due to corrosion can not be reused. Although our country has not made comprehensive statistical statistics on the total economic losses caused by metal corrosion for some time, but only on the end of the 1990s our country on industrial and natural conditions, corrosion preliminary statistical results, coupled with some of the more developed countries abroad on corrosion losses related statistical results, figures, as well as comprehensive consideration of China's corrosion protection conditions than some of the world's more developed countries basic situation. It can be expected that our country due to the metal substation material by environmental corrosion, and the total amount of social economic losses caused is also quite huge.
Polyphenylamine uses mechanical coating method in metals, such as cold-rolled steel, low-carbon steel, aluminum, copper and other surfaces to form a uniform and complete polyphenylamine anti-corrosion film, its anti-corrosion mechanism is to passivate the metal, the metal surface to form a protective oxide layer, and coating suitable coating can lead to corrosion potential migration, thereby reducing the rate of corrosion of the metal.
since 1984 by the University of Pennsylvania chemist Mac Diammid and other redevevanized, chemical structure is expressed as follows:
synthesis of polyphenylamine in a certain solvent environment with a number of specific inorganic in-place interpolation, with electronic transmission, oxidation-restore alternating changes in the structure of organic-inorganic hybrid nanomaterials, the successful preparation of both corrosion-refracturing function and good processing performance of polyphenylamine. Polyphenylamine organic-inorganic hybrid nanomaterials prepared by this technology can be dissolved in water-based or oily solvents to form a solution-like uniform dispersion, long-term will not precipitate.
1. Experimental part
1.1 raw materials
Experimental equipment and instruments see Table 1
Table 1 Experimental equipment and instruments
1.2 raw materials
water-based epoxy resin (Shanghai
Coatings
Institute); Water-based color slurry (homemade); water-based polyphenyl syrup (30% solid) ;(Sa., Shanghai Yutang); wetting dispersants (Shanghai Coatings Institute); thickeners (Dow); deionized water (homemade).
1.3 paint
water-based anticorrosive primer coating formula is below Table 2.
Table 2 Water-based anti-corrosion primer coating formula
1.4
water-based paint
preparation
the water-based epoxy resin and multi-function dispersion machine, 400r/min low-speed dispersion uniform, deionized water and water-based polyphenylamine pre-dispersion uniform backup, to be two dispersed evenly and added to the thickener regulation to the construction degree. After spraying, room temperature maintenance is to be measured for 7 days.
1.5 performance test
the film thickness, adhesion, flexibility, impact resistance, hardness, salt spray resistance, viscosity, table dry, dry, curing, acid and alkali resistance and other properties were tested.
2. Results and
the SEM
of 2.1 polyphenylamine is shown in Figure 1.
1 SEM graph of polyphenylamine
from the SEM graph can be seen the size of synthetic polyphenylamine particles is equal.
UV-Vis map of polyphenylamine is shown in Figure 2.
Figure 2 Polyphenyl UV-Vis
can be found in Figure 2 that the absorption of polyphenylamine is greater than that of polyphenylamine, doping in 334nm there is an absorption peak compared to the normal polyphenylamine red shift, at 638nm the wider absorption is due to n-n-electron corresponding to the electron ring structure of the electron transfer caused by the purple absorption. The red shift produced at 639nm indicates that doping occurs mainly on polyphenyl-benzene nitrogen atoms, not benzene nitrogen atoms. Polyphenylamine after doping, compared with its natural state, the interaction between molecules decreased significantly, the structure of the free chain form, the energy level of electron leap can be reduced, resulting in red migration.
2.2 polyphenyls primer anti-corrosion performance
in the primer to add 0% to 2% of the water-like polyphenylamine slurry (30% solid), after 7 days of conservation for salt mist, acid-resistant alkali and salt-resistant water experiments. Among them, acid-resistant alkali is used in concentrations of 5% sulphuric acid and 5% sodium hydroxide, salt water-resistant experiments are used in 3.5% salt water. The test results are shown in Table 3 below.
table 3 primer anti-corrosion performance test
from the table above can be seen with the increase of polyphenylamine addition, anti-corrosion performance gradually increased. Anti-corrosion performance and economic performance are optimal when the addition is 2%. Therefore, the optimal addition of polyphenylamine is 2%.
2.3 polyphenyls anti-corrosion primer technical indicators
when the amount of polyphenylamine added is 2%, the technical indicators are shown in Table 4 below.
table 4 Polyphenyl film performance is
3. Conclusion:
a series of experiments, it is found that the anti-corrosion performance of the primer after the use of water-like polyphenylamine has been significantly improved. The performance is optimal when the addition is 2%. Therefore, the optimal addition of polyphenylamine is 2%.