Synthesis And Properties Of Sulfonated Epoxy Resins

By using chemical modification method, hydrophilic groups such as sulfonic acid was introduced into bisphenol A epoxy resin, consequently, a kind of epoxy resin with high sulfonated degree was synthesized. The chain of the resin contains a large number of hydrophilic sulfonic acid with which can form a stable dispersion system in water. Direct and indirect methods were conducted in synthesizing sulfonated resin. For the former one, two different sulfonating agent H2SO4 and chloride sulfuric acid were used to sulfonate epoxy resin directly. And then, the relation between the amount of sulfonating agent being used and the structure of the product, sulfonation degree, surface properties, foaming and dispersing properties were discussed, respectively. For the indirect method, sodium sulfite was firstly used as sulfonating agent for the sulfomethylation of bisphenol A, as a consequence, the bisphenol A were hydrophilic as the introducing of methanesulfonic acid groups, then this bisphenol A was reacted with epoxy chloropropane, and water-based epoxy with methanesulfonic acid groups was synthesized. The key of the indirect method was the sulfomethylation of bisphenol A, then the phenolic formaldehyde ratio, sulfonated content on water-soluble, surface properties, viscosity and particle size were studied primary.1. NMR Determination of the degree of polymerization of epoxy resin and functionalityIn this paper, the area of resin epoxy proton peaks, aromatic proton peaks,methylene proton peaks and methyl proton peaks in the bisphenol 1H-NMR spectra were formulating a equation sets, with which can determine simultaneously the polymerization degree (n) and functionality (Fn) of the epoxy resin, then the molecular weight (Mn) and epoxy equivalent (EEW) of epoxy resin were achived.2. Sulfonation of epoxy resin by concentrated sulfuric acidA series of sulfonated epoxy resin with different sulfonation degree was synthesized by using concentrated sulfuric acid with different types of epoxy resin E-20, E-44 and E-51. Structure of the product and the properties were characterized by NMR and the material ratio on the product's dynamic surface tension, critical micelle concentration, foaming and dispersing properties were studied. The results show that the methyl of the epoxy resin was sulfonated, benzene ring was not sulfonated and the sulfonation degree range was 288%-945%. When the molar ratio of epoxy resin with acid was 1:10, the product had the lowest sulfonation degree. Meanwhile, the smaller the molecular weight of epoxy resin, the lower of the sulfonation degree. The higher product concentration and the smaller sulfonation degree; the higher molecular weight of epoxy resin and the higher dynamic surface activity,and also the smaller CMC. The foaming capacity of the sulfonated epoxy resin was not so good; however, the foam stability is good. For the same series of sulfonated epoxy resin, with the increasing of the -SO3- group in molecule, the foaming ability decreased and foam stability enhanced. The dispersion ability was poor; dispersion stability was good. With the increasing of sulfonation degree and the molecular weight of epoxy resin, dispersion ability enhanced gradually.3. Chlorosulfonic acid sulfonated epoxy resinBy using chlorosulfonic acid as sulfonating agent, a series of sulfonated epoxy resin were obtained. NMR and IR were used to characterize the structure and properties of the products and the material ratio on the product's dynamic surface tension, critical micelle concentration, foaming and dispersing properties were studied. The results showed that when the molar ratio of epoxy resin and acid was 1:6, the product had the highest average degree of sulfonation; the higher the molecular weight of epoxy resin, the lower of sulfonation degree. The higher product concentration and the smaller sulfonation degree the higher molecular weight of epoxy resin, the higher dynamic surface activity, and also the smaller CMC. The sulfonated epoxy resin had a poor performance of foaming, but the foam stability was good. They also had a poor dispersion, but dispersion stability is good.4. Sulfomethylation epoxy resinBy using sodium sulfite as the sulfonating agent for the sulfomethylating of bisphenol A firstly, the bisphenol A would be hydrophilic as a result of the introduction of the structure of methyl sulfonic acid, then this bisphenol A was reacted with the epoxy chloro propane and water-based epoxy resin with methyl sulfonic acid groups were synthesized. By studying the water solubility and stability of sulfomethylated bisphenol A obtained from different sulfonating agent and found that the sodium sulfite is most suitable sulfonating agent for the sulfomethylation of bisphenol A. The influence of proportion of the phenolic formaldehyde ratio and the dosage of sulfonated agent on surface tension and viscosity of sulfomethylated bisphenol A were discussed, finding that when the phenolic formaldehyde ratio is too large, the reaction was not completely; the amount of sulfonating agent had little effect on the surface tension and viscosity, the proportion of sulfonated phenolic formaldehyde was the key to the surface tension and viscosity. The result showed that the greater the proportion of sulfonated phenolic, the greater the surface tension and viscosity. Meanwhile, all the products had a good solubility in neutral and alkaline water. The effect of the material ratio on the water solubility, surface properties, viscosity and particle size of ECHNA were studied, the surface tension and viscosity of products from different materials ratio were similar, while the average particle size of emulsion ECHNA increased with the amount of ECH,in which ECHNA-32 had the narrowest size distribution, and size distribution of ECHNA-51 reached 1; all the obtained product can be dispersed in water.