Synthesis of heat-resistant benzoxazine-based polyfluorene and its reversible temperature-sensitive fluorescence

- A main-chain benzoxazine-based polyfluorene (BluePF-BZ) with T-sensitive fluorescent property was first reported.
- The mechanism of T-sensitive fluorescent property for BluePF-BZ/E44 + D230 was studied by model simulation.
- The BluePF-BZ/E44 + D230 possessed high thermal spectral stability and reversible fluorescent response at high temperature.
- This work will enrich species of T-sensitive fluorescent polymer, and extend scope of polyfluorenes for T-sensitive property.

A novel benzoxazine-containing temperature T-sensitive fluorescent polyfluorenes (BluePF-BZ) had been prepared. A benzoxazine monomer (BHPF-paa) was firstly synthesized with 9,9-Bis(4-hydroxyphenyl)fluorene, propargylamine and paraformaldehyde through Mannich condensation reaction. The as-prepared BHPF-paa was then incorporated into the preparation of polyfluorenes, and the main-chain BluePF-BZ could finally be obtained. The structures of the obtained monomer and polyfluorenes were characterized by 1H NMR and FTIR. The BluePF-BZ was finally incorporated into epoxy resin (E44 + D230) to fabricate the T-sensitive material. The thermal stability, optical stability, and T-sensitive fluorescent properties of BluePF-BZ/E44 + D230 were investigated. The BluePF-BZ/E44 + D230 system showed high spectral thermal stability and reversible T-sensitive fluorescent response in relative high temperature (>433 K). To the best of our knowledge, this is the first report about the T-sensitive fluorescent property of PF. Its mechanism of T-sensitive fluorescent property was also studied by comparative experiment and molecular simulation.

122