Study on the preparation of a new type of water based polyaniline composite anticorrosive coatings2016.10.27 08:44
The serious corrosion of metals, to the national economy has brought huge losses, the current protection of metal equipment is mainly to the main anti-corrosion coatings. Due to the defects of the coating itself, it is difficult to be used as a physical barrier layer to completely prevent the corrosion of metal, such as oxygen, hydrogen ion and so on, and most of the anti-corrosion coating solvent damage to the environment, so that its application is limited.
Polyaniline (PANI) is a new kind of functional polymer material, has the advantages of low cost, simple synthesis, high chemical stability and environment stability and other advantages, has broad application prospects in energy, electromagnetic shielding, antisepsis and electrochromic etc.. The polymerization of PANI- asbestos composite by emulsion, which is the main anticorrosive filler in polymer emulsion with excellent performance as the membrane material to prepare anticorrosion coating, the ordinary iron on the anti-corrosion properties were investigated (electrochemical performance) 1-4.
1 test section
1.1 raw materials and equipment
The main raw materials: Twelve aniline and benzene sulfonic acid, ammonium persulfate, asbestos powder, polymer emulsion, mica, water-based asphalt, zinc phosphate, silicon dioxide, nano scale, coupling agent etc..
Main instrument: polymerization device, electric heating constant blast drying box, Shanghai Chen Hua electrochemical workstation, etc..
Synthesis of 1.2PANI- asbestos composite
First, a certain amount of asbestos powder and twelve benzene sulfonic acid be added into the reaction kettle, according to the process of polyaniline synthesized by emulsion polymerization, with twelve alkyl benzene sulfonate as emulsifier, ammonium persulfate as initiator to prepare polyaniline, the reaction after a few hours, the product is dried, crushed, namely PANI- asbestos compound.
1.3 preparation of anticorrosive coatings
PANI- asbestos compound, polymer emulsion, precipitated silica, mica, asphalt, zinc phosphate, silicon dioxide, nano scale mixing, grinding prepared according to a certain proportion, moderate viscosity of coatings.
Preparation of 1.4 polyaniline anticorrosive coating
Pretreatment of 1.4.1 iron
With 150 mesh and 600 mesh 80cm metallographic sandpaper * 45cm * 1cm iron polished mirror, and then immersed in acetone and ethanol pretreatment to remove the organic impurities, finally iron leached with distilled water, acetone drying, stand-by.
Preparation of 1.4.2 coating
The prepared coating is evenly coated on the prepared iron, according to GB1727 - 92 "general preparation of paint film" preparation of polyaniline film, dry naturally, 5-12 tested the.
1.5 coating electrochemical performance test
The electrochemical methods through experiments, respectively by cyclic voltammetry and electrochemical impedance spectroscopy to investigate the corrosion resistance of the coating, the specific process is as follows: the preparation of the side anticorrosion coating and without addition of polyaniline anticorrosive filler coatings were coated on 10mm * 10mm * 1mm with the iron sheet, and then prepare a the blank sheet, then put 3 pieces of iron on the other side of paraffin wax seal, has never been one side (side is coated with lead wire), electrochemical testing system together. Then the NaCl solution is 3 pieces of iron were immersed in 5%, under the sealing condition of the coating of cyclic voltammetry and electrochemical impedance test.