A low-dielectric, high-heat-resistant vinylbenzyl-terminated bisphenol A formaldehyde resin

Abstract

The need for thermosetting resins with low dielectric properties and high-heat-resistance has increased due to the miniaturization, high frequency and high integration of electrical and electronic devices. In this work, the hydroxyl groups of the bisphenol A moiety were modified with bulky and low-polarity groups to investigate the structure–property relationship. With a low dielectric constant (D_k) and dielectric loss (D_f), this molecular design improved the high-frequency dielectric performance by effectively suppressing orientational polarization. Two different bisphenol A derivatives were converted into novel vinylbenzyl-terminated bisphenol A ethers i.e., vinylbenzyl tetramethyl bisphenol A (V-TMBP) and vinylbenzyl bisphenol A formaldehyde (V-BPF) via Williamson's synthesis. Fourier transform infrared (FT-IR), ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy confirmed the chemical structures. FT-IR and differential scanning calorimetry (DSC) were used to investigate the curing behaviours; an exothermic peak representing homopolymerization of terminal vinyl groups was observed. Combining the polymerization conditions and the optimized chemical structure produced a vinylbenzyl bisphenol A formaldehyde resin, having an exceptional dielectric performance with D_k = 2.42, D_f = 0.0065 at 10 GHz and a high glass transition temperature (T_g) of 290 °C, and a vinylbenzyl tetramethyl bisphenol A resin with D_k = 2.60, D_f = 0.0046 at 10 GHz and a T_g value of 250 °C. In conclusion, the vinylbenzyl bisphenol A formaldehyde resin has several outstanding features making it an excellent choice for use in high-performance fields, including aerospace and advanced microelectronics.