An unsymmetrical phosphinated benzoxazine (4) was prepared from 6-(1-(4-aminophenyl)-1-(4-hydroxyphenyl)ethyl)-6H-dibenzo[c,e][1,2]oxaphosphinine 6-oxide through a four-step procedure. The first step is reaction of (1) with 2-hydroxylbenzaldehyde, yielding (2) with an o-hydroxy phenylimine linkage. The second step is the reduction of imine linkage by sodium borohydride, forming (3) with a secondary amine structure. The third step is the simultaneous mannich condensation of phenol with furfurylamine and ring closure of the secondary amine, forming the unsymmetrical phosphinated benzoxazine (4). The thermal properties of polybenzoxazine P(4) were evaluated. Thermal mechanical analyzer shows that the Tg value is 249 oC, with a coefficient of thermal expansion of 29 ppm/oC. The 5% decomposition temperature is 376 oC, with a 52% char yield at 800 oC. The dielectric constant at 1 GHz is 3.3 U, and the dissipation factor is 7.9x10<sup>-3</sup> U.

Synthesis and properties of unsymmetrical phosphinated benzoxazines

255th National Meeting (2018)

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