| The water-based epoxy reasin can be prepared and used with very little or withoutorganic compound(VOC), therefore, it is environment-friendly and very attractive in manyapplication fields. In recent years, much more attention has been paid to preparation andapplication of the water-based epoxy reasin.This thesis adopts chemical modified method to prepare water-based resins of theepoxy resin E-51. Firstly, epoxy resin was used to react with acrylic to produce epoxyacrylate, then the products side hydroxyl of epoxy acrylic resin was used to react withemaleic anhydride to produce the modified resin containing hydrophilic carboxyl andunsaturated double bonds(EpB). EpB can be crosslinked, neutralized to salt by addingorganic base, and then water was added into the EpB salts solution to produce stableemulsion system. The optimal reaction conditions were optimized, and the stability ofemulsion was discussed, and the appropriate curing system and curing conditions wasoptimized also. Polyaniline (PANI) and SiO2/PANI composite particles were prepared byemulsion polymerization, and the properties of epoxy composite coatings were tested.The results showed that the structure of the modified resins is the target product, andthe products have good thermal stability. With molar ratio of n(EpA):n (anhydride)=1:2,and with organic base to neutralize at60℃, the stable emulsion system can be formedwith higher solid content. Under room temperature, the coatings cured with benzoylperoxide-N,N-dimethyl aniline system is superior to that cured with sodium persulfate-sodium bisulfite system; better curing effect can be reached under median temperature(100℃120℃) under phased curing (50℃/1h+100℃/1h). Polyaniline coated onsilica surface (SiO2/PANI) has a higher thermal stability than polyaniline. The coatingmodified with composite particles has better performance than that modified with purepolyaniline in the aspects of water-resistant, pencil hardness, coating adhesion andresistance to salt spray corrosion. |
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