화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.50, No.11, 2201-2210, 2012
Synthesis of 9,9-Bis(4-aminophenyl)fluorene-Based Benzoxazine and Properties of Its High-Performance Thermoset
A benzoxazine (P-bapf) based on 9,9-bis(4-aminophenyl) fluorene (BAPF), phenol, and formaldehyde was successfully prepared using two-pot and one-pot procedures. In the two-pot approach, BAPF initially reacted with 2-hydroxybenzaldehyde, leading to 9,9-bis(4-(2-hydroxybenzylideneimino) phenyl) fluorene. The imine linkages of 9,9-bis(4-(2-hydroxybenzylideneimino) phenyl) fluorene were then reduced by sodium borohydride, forming 9,9-bis(4-(2-hydroxybenzylamino) phenyl) fluorene. Finally, paraformaldehyde was added to induce ring closure condensation, forming benzoxazine (P-bapf). In the one-pot approach, P-bapf was obtained directly by reacting BAPF, phenol, and paraformaldehyde in various solvents. Among the solvents, we found that using toluene/ethanol (2/1, v/v) as a solvent leads to the best purity and yield. No gelation was observed in the preparation. The structure of the resulting benzoxazine was confirmed by H-1, C-13, H-1-H-1 and H-1-C-13 NMR spectra. P-bapf exhibits a photoluminescent emission at 395 nm under an excitation of 275 nm. After curing, the resulting P-bapf thermoset exhibits T-g as high as 236 degrees C, and the T-g can be further increased to 260 degrees C by copolymerization with an equal equivalent of cresol novolac epoxy. The 5% degradation temperature of the P-bapf thermoset reaches as high as 413 degrees C (N-2) and 431 degrees C (air). The refractive index at 589 nm is as high as 1.70, demonstrating a high refractive index characteristic of fluorene linkage. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 2201-2210, 2012