Study on dispersion and anticorrosion of functionalized graphene oxide in powder coatings (Ⅰ)

Abstract: graphene oxide (go) modified by γ - (2,3-epoxyprolido) propyl triethoxysilane (KH560) was mixed with epoxy resin (GEP) to form functional graphene oxide (FGO), which can effectively improve the dispersion of go, and then make it evenly dispersed in the powder coating The anticorrosive coating was successfully prepared by electrostatic spraying The properties of go and coating were characterized and tested by SEM, FTIR, salt spray test, impact test, contact angle test and aging test The effect of KH 560 content on the dispersion of THF and powder coating was investigated, and the effect of KH-560 modified go content on the coating performance was also investigated The results show that the coating prepared by KH560 functional go has excellent corrosion resistance and mechanical properties Metal has been widely used in the national life, but it is facing the problem of corrosion According to the relevant reports, corrosion brings serious losses to the national economy every year, and also causes certain harm to the environment Coating is one of the most effective protective means and the most widely used anticorrosive technology Epoxy resin and polyester resin are one of the commonly used coating resins, which have excellent performance and are widely used in anticorrosive coatings Go has a stable structure, excellent toughness, hardness and excellent decoration, and has a huge application prospect in various fields But go is hydrophobic, which makes it difficult to use If it is used in powder coating, it can not be mixed with powder to reduce the stability of the coating, thus causing defects on the coating, reducing the anti-corrosion performance of the coating, greatly reducing the feasibility of go application Therefore, it is very important to modify go and improve its dispersibility in powder coating Zhou Nan et al Used GEP as graphene dispersant to improve the dispersion of graphene in organic solvent, and GEP can participate in the reaction, further improving the stability of the coating Parhizkar et al Modified go with tripropyltrimethoxysilane (APTES) APTES modified go not only has covalent bond (amino group and go), but also has condensation reaction between silanol group and hydroxyl group and carboxyl group, which improves the dispersion of go in epoxy resin, and also improves the corrosion resistance Zheng et al Grafted urea formaldehyde on go sheet through polymer polycondensation, which improved its dispersion and corrosion resistance in epoxy resin Ramezanzadeh and others successfully modified go by covalent bond, and obtained epoxy resin anticorrosive coating with good miscibility, which greatly improved the anticorrosive performance In this paper, not only go is used as a special functional filler, but also FGO is used as the reaction object The combination of KH560 modification and GEP can effectively inhibit the second push of graphene, and then the powder FGO is prepared FGO is added to the powder coating to obtain graphene anticorrosive powder coating with excellent dispersion and anticorrosion performance Preparation of FGO: 5g go was separated by ultrasound for 6h to form a few layers of go, 500g THF was dispersed at high speed for 10min, and then placed in the ultrasound equipment The dosage of KH560 (1W%, 2W%, 3W%, 4W%, 5W%, relative to the quality of go) was added into a four port flask with 0.5g acetic acid, reacted in a water bath at 40 ℃ for 8h and 15g respectively GEP (refer to reference 1 for the preparation of GEP) is stirred evenly, cooled and dried at low temperature to obtain powder FGO Fig 1 Sketch of KH-560 modified graphene Fig 1 FGO anticorrosive powder coating and preparation of coating table 1 is the basic formula of powder coating The prepared FGO powder is directly added to the powder coating and stirred evenly, and the FGO anticorrosive powder coating is obtained by Sieving (200 mesh) The FGO anticorrosive powder coating was obtained by electrostatic spraying on phosphated tinplate and solidified for 10 minutes at 200 ℃, with a film thickness of about 70-80 μ M The effect of KH-560 dosage on the dispersion of go was modified by KH-560, and the effect of KH-560 dosage on the dispersion of go was investigated The results are shown in Figure 2 Fig 2 SEM of go modified by different KH-560 dosage can be seen from Fig 2 When the dosage of KH-560 is 0, the accumulation amount of go is small and the dispersion is good When the dosage is 4.0 wt.%, the accumulation amount is the largest That is to say, with the increase of the dosage, the accumulation of go increased and the dispersion decreased When the amount of KH560 is less, it is only coated on the surface of go after hydrolysis, and there is no reaction between KH560, which reduces the π - π interaction of go and improves the dispersion When the amount of KH560 is large, not only the polycondensation reaction with go occurs, but also the self polycondensation reaction, so that the go occurs stacking agglomeration phenomenon The preparation and characterization of FG through infrared spectrum analysis go, kh560-go and the structure change of the coating after curing, the results are shown in Figure 3 A-go; b-kh560-go; C the absorption peaks of 3430cm-11740cm-1 and 1025cm-1 in the infrared spectrum of go, kh560-go and the coating after curing respectively correspond to the characteristic peaks of Oh, C = O and C-O-C, and the absorption peaks of 1640cm-1 and 1410cm-1 correspond to the characteristic peaks of - (C = O) - and - COO - The absorption peak of curve B at 1035 cm-1 is the characteristic peak of Si-O-C, which indicates that go has been modified by KH560 Compared with curve a, the characteristic peaks at 1740 cm-1 and 1410 cm-1 disappear or weaken, which indicates that go has been modified by KH560 The absorption peaks at 810 cm-1 and 1130 cm-1 are the characteristic peaks of Si-O-Si, which indicates the reaction between molecules after hydrolysis of KH560 and the reaction between molecules at 915 cm-1 The absorption peak of KH560 is the characteristic peak of epoxy group The absorption peak of curve C at 1210 cm-1 is the characteristic peak of C-N, no characteristic peak of N-H is found between 154 cm-1 and 1570 cm-1, and no characteristic peak of epoxy group is found at 915 cm-1, indicating that dicyandiamide reacts with epoxy group completely To be continued