Study On Synthesis And Properties Of New Tung Oil Based Epoxy Resin Curing Agents

Epoxy resin, a kind of polymer materials, had been used in many fields. It must be used with the help of curing agent, So there are so many researches are focusing on the development of novel epoxy resin curing agent when the application of epoxy resin were investigated. In this paper, the synthetic process on methyl-a-eleostearate (ME), methyl-a-eleostearate-maleic anhydride adduct (MEMAA), tung oil Anhydride ester tricarboxylic acid (TOBTA), methyl-a-eleostearate-maleic acid ethylenediamine (MEMAE) and methyl-α-eleostearate-maleic acid diamine (MEMAD) were studied. In addition, the cured film performance of MEMAA, TOBTA, MEMAE and MEMAD as curing agents were also investigated with ethylenediamine as control. The research results were as follows:1. With tung oil as raw material, the optimal condition of preparing ME with heteropoly acid as catalyzer were as follows:mole ratio of methanol to oil were 10:1, catalyst dosage were 8%, reaction time were 3 hours and reaction temperature 60℃. And the yield were 95.3%.2. With ME as raw material, the optimal condition of preparing MEMAA with anion resin as catalyer were as follows:mole ratio of ME to MA were 1:1.8, catalyst dosage were 10%, reflux reaction time were 14 hours. And the yield were 71.3% and the total yield were 67.9% caculated with tung oil as raw material.3. With MEMAA as raw material, the optimal condition of preparing TOBTA by solvent saponification acidification method were as follows:KOH solution concentration were 30%, reaction temperature 75℃ and reaction time were 2.5 hours. And the yield were 95.6% and the total yield were 65.0% caculated with tung as raw material, with its amine value 416.3 mg KOH/g (theoretical amine value were 427.2 mg KOH/g).4. With MEMAA as raw material, the optimal condition of preparing MEMAE under nitrogen protection by ethylenediamine (EDA) amidation reaction method were as follows:mole ratio of MEMAA to EDA were 1:6, reflux and reaction time were 10 hours. And the yield were 87.2% and the total yield were 59.2% caculated with tung oil as raw material, with its amine value were 446.3 mg KOH/g (theoretical amine value were 455.2 mg KOH/g).5. With MEMAA as raw material, the optimal condition of preparing MEMAD by ammonia amidation reaction method were as follows:continuous access of ammonia, reflux reaction reaction time were 12 hours. And the yield were 85.6% and the total yield were 58.2% caculated with tung oil as raw material, with its amine value were 475.5 mg KOH/g (theoretical amine value were 552.3 mg KOH/g).6. The results of four kinds of tung oil derivatives (MEMAA、TOBTA、 MEMAE、MEMAD) curing epoxy resin compared with EDA were as follows:the hardness, adhesion, impact strength, tensile strength, water resistance, alkali resistance and flexibility of these four kinds of tung oil derivatives were better than EDA in coating. Furthermore, the prepared curing agent TOBTA was the best one on water resistance, acid resistance; MEMAA was the best one on alkali resistance; MEMAE was the best one on flexibility. However, all of four prepared curing agent showed poor solvent resistance of coating.In conclusion, the prepared tung oil derivatives could improve the basic performance of epoxy resin coating, the result in this paper might provide some theoretical guidance for extending the application scope of tung oil.