Phenolic Formaldehyde Amines Derivatives: Preparation, Characterization And Application In Waterborne Epoxy Resin Formulations

With the enhancement of people's environmental awareness,waterborne epoxy coatings have been widely studied by researchers in recent years.The hyperbranched waterborne epoxy curing agent with temperature-sensitive properties can adjust its phase transition temperature by modifying the terminal group to change the corrosion resistance of waterborne epoxy coating.In this way,we can obtain both environmental protection and corrosion-resistant coatings.In this paper,triethylenetetramine,phenol and paraformaldehyde were reacted to synthesized phenolic formaldehyde amine?PFA?through Mannich reaction.Thermoresponsive PFA derivatives were prepared through the modification of PFA with hydrophilic polyethylene glycol diglycidyl ether?PEG?and hydrophobic E20epoxide resin.The successful preparation of PFA and PFA derivatives were demonstrated by ¹H NMR and GPC characterization.The test of PFA derivative by turbidimetric method showed that the polymer had lower critical solution temperature?LCST?.The phase transition temperature(T_cp)can be changed by adjusting the grafting degree,the pH of solution and the hydrophobic/hydrophilic groups.In addition,when the grafting degree of the hydrophilic group was the same,the T_cp of the polymer with the first graft E20 was lower than the polymer first graft with PEG.It was found that the PFA derivative had photoluminescence properties for PFA polymers by ultraviolet spectrophotometer test.It was effected by pH,concentration,temperature and oxidation time.With the increasing of temperature,the fluorescence intensity of polymer aqueous solution decreases first and then enhances.It was a unique fluorescent properties corresponding with T_cp.PFA derivative was used as curing agent for waterborne epoxy coating.We got that the lower the T_cp was,the stronger the corrosion resistance was,so we can modification the curing agent to make a better use in the waterborne epoxy coating.Coating emited blue fluorescence under the ultraviolet light,which means can be applied to the preparation of fluorescent coatings without any additional fluorescent materials.