Synthesis and Characterization of Cyanate Ester Functional Benzoxazine and Its Polymer
摘要:
The first benzoxazine incorporating cyanate ester group in its structure has been synthesized. The polymerization process investigated by differential scanning calometry (DSC) exhibits two clearly separated exotherm maxima, corresponding to cyanate ester trimerization and benzoxazine, respectively. The nature of each exotherm is studied by Fourier transform infrared spectroscopy (FT-IR). The activation energies for cyanate ester trimerization and benzoxazine ring-opening polymerization are determined by both Kissinger's and Ozawa's methods. Furthermore, both exothermic temperatures observed are lower than those of the published values of benzoxazine and dicyanate ester blends. Thermal properties such as glass transition temperature and char yield are studied by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Those properties are found to be outstanding compared to the reported properties of general benzoxazine resins and polymerized blends of benzoxazine and dicyanate ester, offering a polymeric matrix for composite satisfying many requirements for such a material.
Synthesis of 3,4-Dihydro-2H-1,3-benzoxazines by Condensation of 2-Hydroxyaldehydes and Primary Amines: Application to the Synthesis of Hydroxy-Substituted and Deuterium-Labeled Compounds
作者:R. Andreu、J. C. Ronda
DOI:10.1080/00397910802138629
日期:2008.6.27
Abstract We report the synthesis of several substituted 3,4-dihydro-2H-1,3-benzoxazines by simple ring closure of 2-hydroxybenzylamines with paraformaldehyde. The facile synthesis of the benzylamine precursors from commercially available salicylaldehyde derivatives affords a powerful general synthetic way to prepare a variety of substituted benzoxazines, avoiding the formation of undesirable oligomeric
Synthesis and Characterization of Partially Fluorinated Polybenzoxazine Resins Utilizing Octafluorocyclopentene as a Versatile Building Block
作者:Jingbo Wu、Yang Xi、Gregory T. McCandless、Yinhuan Xie、Remya Menon、Yash Patel、Duck Joo Yang、Scott T. Iacono、Bruce M. Novak
DOI:10.1021/acs.macromol.5b01014
日期:2015.9.8
Two new fluorinated diamine-based benzoxazines using octafluorocyclopentene (OFCP) as a building block have been developed. Monomers were synthesized via two distinct synthetic procedures utilizing the facile nucleophilic addition elimination reaction of OFCP with phenols amenable to a multigram scale-up. The structure elucidation of both monomers was confirmed by H-1, F-19, and C-13 NMR, ATR-FTIR, and high-resolution mass spectrometry. Benzoxazine networks were prepared by a thermally mediated ring-opening polymerization. ATR-FTIR analysis was utilized to monitor the ring-opening reaction of the monomers. The resulting two cured resins exhibit the combined excellent properties of low dielectric constants (k = 3.2-2.6), excellent thermal stability, and high char yields which are suitable for many applications such as flame-resistant materials as well as aerospace and microelectronic industries.