A facile method to prepare biobased flexible polydimethylsiloxane − Benzoxazine resin: Dielectric properties and high heat resistance

For the benefit of meet the industrial demand of integrated circuits for low dielectric constant (k) and the environmental requirements of sustainable development, it is important to prepare biobased benzoxazine resin with low k and high heat resistance by solvent-free method. In this paper, the biobased monomer V-fa containing aldehyde group was synthesized by biobased raw materials furfurylamine and vanillin, and then reacted with amino-terminated polydimethylsiloxane (PDMS) to prepare benzoxazine monomer V-fa-pdms containing schiff base structure by a solvent-free method. Then, the monomer was cured to obtain biobased benzoxazine resin poly(V-fa-pdms), and the heat resistance, mechanical and dielectric properties of poly(V-fa-pdms) were studied. The results indicate that the resin exhibits excellent thermal stability and toughness by combining benzoxazine and PDMS reasonably. The initial thermal decomposition temperature (Tdi, 5% thermogravimetric loss) is 387 °C, and the material also exhibits excellent dielectric properties. When the frequency increases from 1 Hz to 1 MHz, the k of the material decreases from 2.71 to 2.60, and the fluctuation range of dielectric loss is 0.0051–0.0049. With the increase of frequency, both k and dielectric loss show a downward trend. At the same time, the material shows good corrosion resistance in commonly used solvents. These excellent properties of poly(V-fa-pdms) are due to the existence of a high cross-linked network structure formed by multiple cross-linking sites in the polymer network and the combined effect of low k and high heat-resistant PDMS components.