Modification of CaCO3 nanoparticle by styrene-acrylic polymer emulsion spraying and its application in polypropylene material

A novel CaCO3 nanoparticle modification method by a styrene-acrylic polymer emulsion (SAPE) was introduced. The self-made SAPE was sprayed into the nano-CaCO3 slurry system, and SAPE chains were encapsulated onto the CaCO3 nanoparticle surface. The modified CaCO3 nanoparticle mechanism was discussed. Fourier transform infrared spectroscopy confirmed that the SAPE chain was anchored on the nano-CaCO3 surface by the reaction of the SAPE carboxyl group with the hydroxyl group on the CaCO3. The effect of acrylic acid (AA) amount on the activation degree and oil absorption of CaCO3/SAPE composite nanoparticles was investigated. The amount of AA was 2%, and the activation degree and oil absorption of the product were optimal. The estimated grafting efficiency of the CaCO3/SAPE composite nanoparticles was 90.5% when the amount of acrylamide (AAM) was 1.5%. Scanning electron microscopy showed that the CaCO3 nanoparticles could be dispersed uniformly in polypropylene (PP) film and formed a closed integration by SAPE-modified CaCO3. The styrene-acrylic polymer chains that were grafted on the CaCO3 nanoparticle surface could improve the compatibility between the CaCO3 nanoparticles and PP matrix. The PP composite film with modified CaCO3 nanoparticles had a higher tensile strength than that of pure CaCO3 nanoparticles, which can improve the mechanical properties of the PP material. [Display omitted] •Surface modification of CaCO3 nanoparticles was performed by a unique process.•The modified CaCO3 nanoparticle mechanism was elaborated.•The PP with CaCO3/SAPE has a higher tensile strength than that of pure CaCO3.