Preparation and interfacial properties of multifunctional polypropylene/ hollow glass bead composites

Multifunctional composites are a type of material prepared by reinforcing polypropylene (PP) with hollow glass beads (HGBs). This type of composite has various applications in industries such as automotive manufacturing. However, the mechanical properties of such composites can be affected by the compatibility between different interfaces. To improve the overall performance, modifying the interface between PP and HGBs is necessary. Herein, the surface of HGBs was modified using a polydopamine coating to enhance their adhesion to ZnO nanowires (ZnO NWs). The uniform growth of ZnO NWs on the surface of the HGBs afforded a sea urchin-like structure. The structure increased the surface area in contact with the PP matrix, which provided an interlocking effect between the materials. The interfacial interlocking effect improved the interfacial compatibility between the two materials. The addition of 10wt% sea urchin-like HGB led to a 31.7 % increase in tensile strength and a 9.7 % increase in impact strength compared with PP/HGB composites. Additionally, the composites showed improvements in thermal insulation and antimicrobial properties. The thermal insulation properties of the PP composites were further enhanced by the synergistic effect of ZnO and HGBs. ZnO endowed the composites with antimicrobial properties. Furthermore, 5wt% PP/ZnO-HGB composites resulted in 82 % and 68 % inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. In conclusion, the construction of a sea urchin-like topology on the HGBs surface is an effective way to improve the interfacial compatibility, thus enhancing the overall performance of the composites.