Synthesis And Characterization Of Three-and Four-functional Carboxyl Epoxy Curing Agent

The existing high temperature curing agent of epoxy resin and epoxy resin compatibility is poor in low temperature,short storage period,and storage conditions of rigid,cannot satisfy the requirement of resin impregnated.The development and application of low viscosity epoxy dipping glue this article selects the long-chain alcohol acid and glycol,and 1,4-trichlorobenzene benzene anhydride synthesis has good compatibility with epoxy resin,room temperature storage stability of carboxyl type curing agent,The main findings are as follows:(1)Reaction of 10-hydroxydecanoic acid and 12-hydroxystearic acid with 1,2,4-phthalic anhydride was used to synthesize 1-(o-carboxyl n-nonyl ester)-2,4-dicarboxyl-benzene(ONEDB)and 1-(o-carboxyl-11-n-hexyl undecyl ester)-2,4-dicarboxyl-benzene(OUEDB)trifunctional carboxyl-epoxy resin curing agent.The structures of ONEDB and OUEDB were characterized by FT-IR and ~1H NMR..The melting points of ONEDB and OUEDB were determined by differential scanning calorimeter(DSC)at 61.0℃and 46.9℃respectively.Thermogravimetric analysis(TGA)showed that ONEDB and OUEDB had better thermal stability.The activation energies of ONEDB,OUEDB and epoxy resin E51 were 67.2 and 65.2 k J/mol,respectively.(2)Two(2,4-dicarboxyl-1-benzoic acid)-1,6-hexanediol ester(BDBAH)and two(2,4-dicarboxyl-1-benzoic acid)-polypropanediol ester(BDAPGE)were synthesized by reaction of 1,6-hexanediol and ppg-400 with 1,2,4-benzoic acid anhydride,respectively.The structures of BDBAH and BDAPGE were characterized by FT-IR and ~1H NMR.The softening point of BDAPGE is 78.6℃,which meets the expected requirements.The melting point of BDBAH is 198.6℃,and the melting temperature is too high to meet the requirements.The activation energy of curing reaction between BDAPGE and epoxy resin E51 was 62.8k J/mol.(3)The TGA results of the cured products of ONEDB,OUEDB,BDAPGE and epoxy E51 showed that ouedb-e51 had better thermal stability,and its heat resistance was better than that of the cured products of 1,2,4-phthalic anhydride and E51.The mixture of ONEDB,OUEDB,BDAPGE and epoxy E51 was stored at room temperature of 25℃.The viscosity did not change significantly 19 to 20 days ago,while the viscosity of E51 and hexahydrophthalic anhydride significantly increased after 7 days.(4)The impregnated resin system composed of OUEDB,epoxy resin 618 and diluent 622 has good stability under the storage conditions of 100℃sealed storage for20h,25℃sealed storage for 432h,60℃sealed storage for 432h,and 60℃open for one hour a day for 432h.