| 초록 |
A novel diamine, bis(3-aminophenyl)-2,3,5,6-tetrafluo-4-trifluoromethylphenyl phosphine oxide (mDA7FPPO), was synthesized via Grignard reaction, followed by nitration and reduction. The monomer was characterized by FT-IR, NMR, melting point apparatus and utilized to prepare polyimides with 6FDA, BTDA and ODPA via a conventional two-step synthesis; preparation of poly(amic acid), followed by solution imidization. For comparison, bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide (mDA6FPPO), bis(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxide (mDA3FPPO) and bis(3-aminophenyl) phenyl phosphine oxide (mDAPPO) were also utilized. The molecular weights of polyimides were controlled to 20,000 g/mol by off-stoichiometry. The polyimides were characterized by FT-IR, NMR, GPC, TGA and DSC, and solubility, intrinsic viscosity, dielectric constant and refractive index were also evaluated. The novel polyimides exhibited high Tg(228 - 257 °C), excellent thermal stability (> 500oC), low dielectric constant (2.313 – 2.498) and low birefringence (0.0019 – 0.0049). |
