| The concrete track slabs used in high-speed railways are inevitably subject to erosion by natural factors in the wild environment.The subsequent maintenance and repair and the reconstruction of the concrete track slabs after the end of their service life will consume a lot of human,material and financial resources.This paper intends to design a coating that is applied to the surface of concrete track slabs at an early stage to protect concrete track slabs from the bad natural environment and to reduce the cost of repairing and rebuilding concrete track slabs in the later stage.Epoxy resins are widely used in the coatings industry because of their excellent adhesion properties and corrosion properties.The traditional coatings on the market are solvent-based epoxy coatings that are harmful to the human body and harmful to the atmosphere,therefore,this paper intends to design a green environmental protection epoxy resin coating that uses water instead of organic solvents,that is,water-based epoxy resin coating.Waterborne epoxy resin coating refers to the physical or chemical method to enable the lipophilic epoxy resin to exist stably in water in the form of emulsion particles to form a stable emulsion.Since the water-based epoxy resin coating is made by curing the water-based epoxy resin emulsion with a curing agent,the performance of the water-based epoxy resin emulsion greatly affects the performance of the later water-based epoxy resin coating.In this paper,a method for preparing water-based epoxy resin emulsion is designed.The research contents are as follows:First,at the appropriate temperature and initiator conditions,one end of the epoxy resin is used to open the epoxy group of one end of the epoxy group,and non-ionic hydrophilicity such as ether bonds is introduced into the main chain of the epoxy resin molecule.Segment,the epoxy resin modified by polyethylene glycol is both hydrophilic and lipophilic.The epoxy value was used to monitor the reaction process,and the structure of the modified epoxy resin was characterized by fourier transform infrared spectroscopy.The effects of reaction time,reaction temperature,relative molecular weight of polyethylene glycol,initiator type,initiator dosage,initiator dropping method,and the ratio of polyethylene glycol and epoxy resin on the reaction process were studied.The optimal test conditions are: the molar ratio of polyethylene glycol to epoxy resin is 1: 1,the reaction is 6 hours,the reaction temperature is 160 ℃,the relative molecular weight of polyethylene glycol is 4 000,the initiator is potassium persulfate,and the amount is used as the raw material with a molar ratio of 0.75%,the initiator dropping method is to dissolve the initiator in water and slowly add it at a constant speed using a constant pressure funnel to prepare a polyethylene glycol modified epoxy resin self-emulsifying agent with excellent performance.Secondly,under the proper temperature and stirring conditions,the self-comprising emulsifiers and epoxy resins prepared by polyethylene glycol modified epoxy resins were prepared by the reverse conversion method to prepare aqueous epoxy resin emulsions.The epoxy resin will be wrapped by the lipophilic end of the self-made emulsifier,which can be stably present in water due to the action of hydrophilic groups.The effects of emulsification temperature,stirring rate,mass ratio of self-formulated emulsifier and epoxy resin on the stability of aqueous epoxy resin emulsions were investigated,and the morphology and distribution of aqueous epoxy resin emulsion particles were observed with a transmission electron microscope.The best test conditions are: the emulsification temperature is set to 70 ℃,the stirring rate is 1 500 r / min,and the mass ratio of the self-made emulsifier to the epoxy resin is 1: 2,the stability of the prepared aqueous epoxy resin emulsion is the best.And the particle size is 50 nm to 120 nm. |
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