Influences of Ternary Graft Copolymers on the Morphology and Properties of Polypropylene/Calcium Carbonate Composites

The ternary graft copolymers were synthesized by solid-phase grafting maleic anhydride (MAH), methyl methacrylate (MMA), and butyl acrylate (BA) onto polypropylene (PP), and applied in the interfacial modification of the PP/Calcium carbonate (CaCO₃) composites. Fourier transform infrared (FTIR) spectroscopy was used to analyze the structure of the ternary graft copolymers. Scanning electron microscopy (SEM), thermogravimetry (TG), differential scanning calorimetry (DSC), and dynamic rheological testing were used to investigate the morphology and the properties of the composites. FTIR results confirmed the occurrence of the solid-phase graft copolymerization, and SEM exhibited the improvement of the compatibility between PP and CaCO₃ by PPTM. The properties testing showed that PPTM significantly contributed to the reinforcement of the composites in terms of mechanical properties, thermal properties, and rheological properties by acting as interfacial modifiers and plasticizers. The preferable loadings of PPTM for the properties improvement of the PP/CaCO₃ composites were between 7 and 9 phr.