Synthesis and characterization of low dielectric constant polybenzoxazines with different fluorine contents

The rapid development of integrated circuits puts forward higher requirements for low dielectric constant polymers. In this study, two fluorinated benzoxazine monomers, bis-(3,4-dihydro-3-(4-fluoro-3-(trifluoromethyl)phenyl)-2H-1,3-benzoxazine)isopropane (BA-ftfa) and bis-(3,4-dihydro-3-(4-fluoro-3-(trifluoromethyl)phenyl)-2H-1,3-benzoxazine)isoperfluoropropane (BAF-ftfa), were successfully synthesized. Differential scanning calorimeter (DSC) was used to monitor the thermal curing behaviors of the monomers and their mixtures. Five groups of polybenzoxazine samples with different fluorine content (25% ~ 35%) were obtained by copolymerizing the two monomers with different mass ratios. The effects of fluorine content on dielectric properties were investigated and the results show that PBAF-ftfa with the highest fluorine content has the lowest dielectric constant of 2.53 at 1 MHz. Furthermore, the results of thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) show that all polymers possess excellent thermal stability and exhibit high glass transition temperatures over than 180°C.