Study on the mechanism of waterborne polyurethane modified ultrafine ground calcium carbonate and its properties in polypropylene plastics

Abstract Ground calcium carbonate (GCC) has the effect of reducing the incremental cost and improving the application performance as a plastic filler. In this study, waterborne polyurethane (WPU) was employed as a novel modifier for the wet modification of GCC. Polypropylene (PP)‐based composites incorporating GCC were then prepared for mechanical properties testing. The oil absorption value, wetting contact angle, and settling time in kerosene indicated that the modified GCC achieved an excellent modification effect with a WPU dosage of 2.0 wt%. The X‐ray Diffraction, Fourier Transform Infrared Spectroscopy, and X‐ray Photoelectron Spectroscopy results indicate that WPU was successfully coated on the surface of the GCC. SEM images revealed improved wettability and compatibility of GCC in the composites after modification. The mechanical tests showed that the GCC‐WPU/PP composites exhibited enhanced properties, including a flexural strength of 107 MPa, impact strength of 9.54 kJ/m 2 , tensile strength of 29.7 MPa, and an elongation at break of 30.9%. Highlights WPU was innovatively used as a modifier of GCC. An optimal modification effect was gained at the low dosage (2.0 wt%). GCC has excellent compatibility and wettability in PP composites. The obtained PP‐based composites have better mechanical properties. The study has the potential to apply GCC in plastics and other industries.