| Epoxy resin is a kind of thermosetting polymer material with good adhesion,electrical insulation and chemical stability.It is widely used as a resin matrix for coatings,adhesives and composites.As one of the components of waterborne epoxy resin coating,epoxy curing agent has an indispensable role in the system.However,the traditional polyamine curing agent has a large difference with epoxy resin in solubility parameter,and volatile irritating odor caused a heavy burden to the environment.Therefore,the development of a combination of emulsification and curing function of environmentally friendly modified curing agent is of great significance.In this paper,the basic structure of carboxylic acid with different number of carbon atoms and the corrosion resistance of the coating were studied.It mainly studied the relationship between these modified curing agent and the corrosion resistance of the coating:the monofunctional carboxylic acid modified curing agent(acetic acid,octanoic acid,lauric acid,myristic acid,oleic acid),the bifunctional carboxylic acid modified curing agent(oxalic acid,hexanedioic acid),the polyfunctional carboxylic acid modified curing agent(benzoic acid,salicylic acid).And the modification effect of the carboxylic acid modified curing agent with different carbon chain structure was compared.The research contents and results are as follows:(1)The surface treatment of tinplate metal samples was coated with monofuncti onal carboxylic acid modified curing agent(acetic acid,octanoic acid,lauric acid,m yristic acid and oleic acid).The result showed that the modified curing agent had ce rtain anti-corrosion ability.In addition,the metal surface treated with octanoic acid modified curing agent was relatively smooth,and the corrosion resistance has increas ed in the maximum.It indicated that 8 carbon atoms of the bitterness of the modifi ed effect was best in the monofunctional carboxylic acid modified curing agent.(2)The surface of tinplate metal sample was coated with bifunctional carboxylic acid modified curing agent(oxalic acid and hexanedioic acid).The results showed that the corrosion resistance of metal surface treated with hexanedioic acid modified curing agent has increased in the maximum.This showed that hexanedioic acid modification effect was the best in the bifunctional carboxylic acid modified curing agent.(3)The surface treatment of tinplate metal samples was coated with benzoic acidmodified curing agent and salicylic acid modified curing agent.The results showed that the modification effect of salicylic acid was better.(4)The modification effect of octanoic acid,hexanedioic acid and salicylic acid and the performance of the corresponding waterborne epoxy coating were compared.The result showed that the order of modification was as follows: octanoic acid> hexanedioic acid>salicylic acid,octanoic acid modified curing agent was more suitable for use in waterborne epoxy coatings. |
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