Deprotection‐free preparation of propargyl ether‐containing phosphinated benzoxazine and the structure–property relationship of the resulting thermosets

Abstract

Generally, protection and deprotection procedures of amino groups are required in preparing propargyl ether-containing benzoxazines. In this study, we report a facile, deprotection-free preparation of a propargyl ether-containing phosphinated benzoxazine (2) from the nucleophilic substitution of a phenolic OH-containing phosphinated benzoxazine (1) and propargyl bromide in the catalysis of potassium carbonate. The structure of (2) was characterized and confirmed by a high-resolution mass spectrum, 1H, 13C, 1H-1H, 1H-13C nuclear magnetic resonance (NMR) spectra, and X-ray single crystal diffractogram. infrared (IR) and differential scanning calorimetry were used to monitor the ring-opening of benzoxazine and crosslinking of propargyl ether. The microstructure and the structureproperty relationship of the resulting homopolymers and copolymers are discussed. The Tg of homopolymer of (2) is 208 degrees C by dynamic mechanical analysis, the coefficient of thermal expansion is 43 ppm/degrees C, and Td 5% (N2) is 393 degrees C, respectively, which are higher than those of the homopolymer of (1). Similar trends were observed in the copolymerization system. The results demonstrate the beneficial effect of crosslinking afforded by the propargyl ether group is higher than that by the phenolic OH group. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 201

The flame‐retardant properties and mechanisms of poly(ethylene terephthalate)/hexakis (para‐allyloxyphenoxy) cyclotriphosphazene systems

“…Figure (A) shows the chemical structure changes in RT‐FTIR spectrogram at different temperature in KBr disk. When the temperature raised to 250°C, the appearance of band at 3600 cm −1 was attributed to phenolic hydroxyl groups and the stretching vibration of ether at 1250 cm −1 disappeared, which was caused by the exothermic Claisen rearrangement of allyl ether groups . Additionally, thermograms were obtained by scanning the sample twice from 30°C to 280°C with a heating rate of 10°C min −1 .…”

Reaction mechanism and synergistic anticorrosion property of reactive blends of maleimide-containing benzoxazine and amine-capped aniline trimer

“…[3][4][5][6][7][8][9][10][11][12] Incorporation of another polymerizable group to benzoxazine compounds could increase the crosslinking densities and the glass transition temperatures (T g ) of the corresponding polybenzoxazines. [13][14][15][16] Phosphorylation of benzoxazines improves the ame retardancy of the corresponding polymers. [16][17][18][19] The benzoxazines possessing hydroxyl 20,21 and carboxylic acid 22,23 groups exhibit relatively low polymerization temperatures and good processing properties.…”

Synthesis of borosiloxane/polybenzoxazine hybrids as highly efficient and environmentally friendly flame retardant materials

“…The methylphosphine oxide‐containing PBZ exhibited a LOI value of 38 . The cyclic organic phosphorus 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐containing PBZs also achieved UL‐94 V‐0 grade . Interestingly, it was found that the incorporation of halogens and P elements did not appear to fulfill environmentally friendly flame retardation due to abovementioned problems.…”