Synthesis,Characterization, and Functionalization of Hyperbranched Poly(ether ether ketone)s with Phenoxypheyl Side Group

Novel fluoride‐teminated hyperbranched poly(ether ether ketone) with 4‐phenoxyphenyl side group (HPEEK‐F) was prepared from 2‐(4‐phenoxyphenyl)‐1,4‐diphenol (A₂) and 1,3,5‐tris4‐(4‐flourobenzoyl) phenoxy]benzene (B₃). An end‐capping approach was used to synthesize tertiary amino‐terminated fluorescent (HPEEK‐DMA) and phenyl ethynyl‐terminated self‐crosslinking poly(ether ether ketone)s (HPEEK‐PEP). These three polymers have the same backbone structure and degree of branching (DB=0.67), and different terminal groups. The nature of the terminal group was shown as the influences of the glass transition temperature (T_g) and decomposition temperature (T_d) of polymers. The T_g of HPEEK‐F and HPEEK‐DMA are 30°C lower than HPEEK‐PEP, whereas the T_d of HPEEK‐F are 90°C and 50°C higher than HPEEK‐DMA and HPEEK‐PEP, respectively. The HPEEK‐DMA fluoresce blue‐green in solid and in solution. This kind of hyperbranched polymer contains a large amount of terminal chromophore groups which can easily lead to the formation of intramolecular excimers. The fluorescence signal was decreased with increasing acidity, furthermore, the two peaks at 466 nm and 507 nm indicated a blue shift occurred. After curing, the HPEEK‐PEP displayed a T_g at 235.5°C, which is 100°C higher than original polymers. Thermally cured samples show good anti‐chemical corrodibility in DMF, THF, DMAc and NMP solvents.