Synthesis and characterization of fluorinated isomeric polybenzoxazines from core-fluorinated diamine-based benzoxazines

Abstract

In this work, we describe the design and synthesis of novel isomeric (para- and meta-) core-fluorinated polybenzoxazines from bis(benzoxazine)-containing monomers with 1,4-tetrafluorobenzene or 4,4′-octafluorobiphenylene dioxyphenylene central units. The new core-fluorinated polybenzoxazines were prepared as dimensionally stable free-standing films without loss of any useful properties. Thermal polymerization of benzoxazine monomers was analyzed using differential scanning calorimetry technique. Peculiarities of the polymerization behavior as well as thermal characteristics of the synthesized fluorinated polybenzoxazines could be related to the position of oxazine ring in the benzoxazine monomer. Furthermore, the effect of the electronic character of the groups surrounding the oxazine ring on the ring-opening polymerization process has been studied. We show correlation between isomeric structure of the fluorinated polybenzoxazines and their physical properties. The resulting polymer films possess a set excellent characteristics including high thermal stability (up to 491 °C), hydrophobicity (water contact angles above 90°), moisture resistance (water uptake less than 1% under water environment for one week), low dielectric constants and loss factors (2.35–2.61 and 0.0071 to 0.0248 at 105 Hz, respectively). This makes the synthesized polymer resins attractive for microelectronics and many other emerging applications.