Functionalized Graphene Improves the Crystallization Behavior of Polypropylene Composites

ABSTRACT Due to insufficient rigidity, the application of polypropylene (PP) is subject to many limitations. Adding graphene to the polymer materials can greatly enhance the performance of the product, which is also the most promising industrial application field for graphene. Therefore, this study used phosphorus‐modified graphene oxide (P‐FGO) as a novel nucleating agent to modify PP and systematically investigated the mechanism of P‐FGO's effect on the crystallization behavior, thermal stability, and mechanical properties of PP. First, P‐FGO was successfully synthesized and was confirmed by Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and other tests. The polarized optical microscopy (POM) results showed that when the addition of the P‐FGO amount was less than 0.5%, the nucleation of the PP composite increased with the increase of the amount of P‐FGO, and the crystallization became more and more complete. It can be seen from the crystallization curves and melting curves that the crystallinity and melting temperature also increase with the increase in the amount of P‐FGO, indicating that FGO can serve as a nucleating agent to promote the crystallization of the PP, which can improve the crystallinity. As a multifunctional nucleating agent, P‐FGO solved the problems of insufficient strength (tensile strength increased to 34.04 MPa) and poor thermal stability (melting temperature increased to 165.12°C) of PP materials. This study provided a low‐cost, high‐performance nucleating agent solution for the design of polymer composites, particularly suitable for the development of high‐performance PP materials in automotive, home appliance, and other related sectors, filling the application gap of phosphorus‐modified graphene oxide in crystallization control.