Furan-containing benzoxazine monomers, 3-furfuryl-3,4-dihydro-2H-1,3benzoxazine (P-FBz) and bis(3-furfuryl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (BPA-FBz), were prepared using furfurylamine as a raw material. The chemical structures of P-FBz and BPA-FBz were characterized with FTIR, 1 H NMR, elemental analysis, and mass spectrometry. Formation of furfurylamine Mannich bridge networks in the polymerizations of P-FBz and BPA-FBz increased the cross-linking densities and thermal stability of the resulting polybenzoxazines. P-FBz-and BPA-FBzbased polymers also exhibited high glass transition temperatures above 300 8C, high char yields, and low flammability with limited oxygen index values of 31. The dielectric (D k ¼ 3.21-3.39) and mechanical properties (high storage modulus of 3.0-3.9 GPa and low coefficient of thermal expansion of 37.7 -45.4 ppm) of the P-FBzand BPA-FBz-based polymers were superior or comparable to other polybenzoxazines.
A benzoxazine compound with a maleimide group, 3-phenyl-3,4-dihydro-2H-6-(N-maleimido)-1,3-benzoxazine (HPM-Ba), was prepared from N-(4-hydroxyphenyl)maleimide, formaldehyde, and aniline. The chemical structure of HBM-Ba was identified by FT-IR, 1 H-NMR, and elemental analysis. HPM-Ba showed a melting point of 52-55°C and good solubility in common organic solvents. HPM-Ba showed a twostage process of thermal polymerization. The first stage arose from the polymerization of maleimide groups, and the second one was the ring-opening reaction of benzoxazine groups. Fusible polymaleimides with a Tg of around 100°C could be obtained by thermally polymerizing HPM-Ba at 130°C. Further polymerizing the polymaleimides at 240°C resulted in a completely cured resin showing a Tg at 204°C. Good thermal stability and self-extinguishing behavior was observed with the cured polybenzoxazine resins.
A benzoxazine compound (FDP-FBz), which possesses a fluorene group and two terminal furan groups, and its corresponding cross-linked polymer (CR-FDP-FBz) have been prepared using 4,4 0 -(9-fluorenylidene)diphenol (FDP), furfurylamine, and formaldehyde as precursors. The chemical structure of FDP-FBz has been characterized with Fouriertransform infrared and 1 H nuclear magnetic resonance spectroscopies. FDP-FBz displays a melting point at about 173 C and a processing window of 52 C as well as good solubility in common organic solvents. As a result, FDP-FBz can be fabricated in both molten and solution processes. Under an excitation at 365 nm, FDP-FBz exhibits a photoluminescent (PL) emission at about 445 nm. The PL intensity of FDP-FBz is as high as sixfolds of the intensity recorded with FDP. CR-FDP-FBz displays a glass transition temperature of 215 C, a high storage modulus of 3.1 GPa, a 10% weight loss at 384 C, and a high char yield of 56 wt % (900 C, in nitrogen). Moreover, CR-FDP-FBz has a high refractive index of about 1.65 as a result of incorporating fluorene groups to its structure. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4020][4021][4022][4023][4024][4025][4026] 2010
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.