Polyethylenimine Assisted Bio-Inspired Surface Functionalization of Hexagonal Boron Nitride for Enhancing the Crystallization and the Properties of Poly(Arylene Ether Nitrile)

Semi-crystalline poly(arylene ether nitrile) (PEN) has exhibited remarkable potential in various fields. However, the inherent drawbacks of PEN such as slow crystalline rate and low crystallinity limit its further development. To alleviate this problem, the choice of nanofiller as nucleation agent and the interfacial compatibility between nanofiller and PEN matrix are two momentous factors that need to be considered. Accordingly, in this work, functionalized hexagonal boron nitride (h-BN@(PDA+PEI)) was successfully synthesized via polyethylenimine (PEI) assisted bio-inspired surface functionalization, and then homogeneously dispersed in the PEN resin using solution casting method to obtain functional polymer nanocomposite films with strengthening the crystallization behavior, mechanical and dielectric properties. Various testing methods including differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), and polarizing microscope (POM) were applied to intricately analyze the effect of h-BN@(PDA+PEI) on the crystallization behavior of PEN composites. The testing results certificated that the h-BN@(PDA+PEI) can effectively improve the crystallinity (from 6.56% to 14.90%), and the spherulite size of PEN was reduced while the nucleation density of nanocomposites was raised. Furthermore, the non-isothermal crystallization kinetics demonstrated that 2 wt% h-BN@(PDA+PEI) could significantly reduce the cold crystallization temperature (Tp) and the crystallization activation energy (Ea) (from 359.7 KJ/mol to 292.8 KJ/mol), while it improved the crystallization rate (Kc) of PEN. In addition, the mechanical and dielectric properties of nanocomposite films were also reinforced to further broaden the application of semi-crystalline PEN. Therefore, the h-BN@(PDA+PEI) can function as an effectual nucleating agent and enhance the performance of PEN.