کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5181473 | 1380964 | 2014 | 8 صفحه PDF | دانلود رایگان |
A pyridinyl-containing benzoxazine (6) was synthesized from the Mannich condensation of 4-phenyl-2,6-bis(4-aminophenyl) pyridine (2), phenol, and paraformaldehyde. For the purpose of properties comparison, a benzoxazine (7), which is structurally similar to (6) except for the pyridinyl group, was prepared. The solvent effect on the synthesis of (6) was discussed, and toluene/ethanol was found to provide (6) with the best purity and yield. The pyridinyl group provides solubility and acts as a catalyst for the ring opening of benzoxazine, as supported by the forward curing in the DSC thermograms. When curing with epoxy resins, a carbonyl absorption at 1670Â cmâ1 and 192Â ppm was observed in the IR and 13C NMR spectra. It is proposed that the formation a cyclic amide structure is responsible for the absorption. A reaction mechanism including nucleophilic addition, Diels-Alder reaction, and rearrangement was proposed. The pyridinyl group acts as a crosslinking site, and results in thermosets with good thermal properties.
Journal: Polymer - Volume 55, Issue 7, 1 April 2014, Pages 1666-1673