| Epoxy resin has good chemical stability and high performance of adhesion, electricity insulating. It is a keystone of every nation how to manufacture the waterborne epoxy resin in waterborne coatings' industry. Now, there are some defects of our country's products, such as big diameter and bad chemical stability. So, the chemical modification which is carboxylic acid monomer graft copolymerization and adding in some functional monomers to prepare waterborne epoxy resin was carried out. The research project of this paper as followed:1. In order to get the best reaction conditions, the effects of reaction conditions such as polymerization's means, solvent and solvent ratio, initiators, initiators concentration and the ways how to add in, reaction temperature and reaction time had aLl been studied . The results showed that mixed solvent (Solvent S-1: S-2 = 2:1), initiator I-1 at a concentration of 8% as initiator, reaction temperature at 115 C and 5h reaction time are the optimum conditions. Which kinds of the optimum monomers' and ration (a ,b-unsaturated carboxylic acid: monomer M-3: a ,b -unsaturated carboxylic ester = 3:3:2) in graft modification also had been found.2. The reaction kinetics in the optimum conditions is discussed, and the macro-scopical reactive kinetics equation of grafting percent conversion is established, from it, the rate equation is obtained too, which reflects the change of grafting degree with time, that is.3. With FTIR and thermal analysis, graft modification resin has been characterized. The graft point is the carbon atom affiliated hydroxyl group in epoxy resin molecular chains. The neutralization agent and its dose is the most important factor to attain latex with good stability. DMEA was adopted as 1) the neutralization agent, 2) 105% of theoretical neutralizing dose. Some performance of coating film which is prepared by modified resin also has been inspected, that anchoring strength, stiflfhess and impact resistance were improved. |
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