Preparation and properties of novel fluorinated epoxy resins cured with 4-trifluoromethyl phenylbenzimidazole for application in electronic materials

Abstract

A novel 3-trifluoromethyl phenylhydroquinone epoxy monomer (3-TFMEP) and a novel 4-trifluoromethyl phenylbenzimidazole (4-TFMBI) curing agent both with trifluoromethyl moieties were synthesized via a multi-step procedure. Their chemical structures were confirmed by FT-IR and 1H NMR spectra. Herein, we employed 3-TFMEP as the epoxy matrix, and 4-TFMBI as the curing agent or the curing accelerator. Next, we prepared a series of epoxy resins with four kinds of different curing system as 3-TFMEP/Methylhexahydrophthalicanhydride(Mehhpa)/2-methylimidazole (2-MI), 3-TFMEP/Mehhpa/4-TFMBI, 3-TFMEP/2-MI and 3-TFMEP/4-TFMBI in order to investigate the variation of the properties with different curing agents and curing accelerators. The result showed that no matter whether 4-TFMBI was used as the curing agent or as the curing accelerator, the epoxy resin cured with 4-TFMBI exhibited high mechanical and thermal stabilities, as well as low dielectric constant and dielectric loss. In particular, 3-TFMEP/4-TFMBI possessed the highest Td5% (the decomposition temperature of 5% weight loss) of 374 °C, 131 °C higher than 3-TFMEP/Mehhpa/2-MI. Additionally, the storage modulus of 3-TFMEP/Mehhpa/4-TFMBI was 3266 MPa at 25 °C, which was much higher than other kinds of cured epoxy resins. Moreover, 3-TFMEP/4-TFMBI possessed the lowest dielectric constant of 3.38 at 107 Hz among these cured epoxy resins. Therefore, we believed that this novel fluorinated epoxy resin cured with 4-TFMBI containing 3-trifluoromethyl moieties have a great potential for application in the electronic packaging material field.