Controlled synthesis, characterization and application of hydrophobic calcium carbonate nanoparticles in PVC

• Hydrophobic spherical CaCO3 particles were prepared via a DDP inducing process.
• The contact angle of hydrophobic CaCO3 particles was 119.51°.
• The polymorphs were characterized with XRD, FT-IR and TGA.
• The schematic illustration of the reaction was discussed in the end.
• The properties of PVC/CaCO3 composites have been tested such as tensile strength, impact strength, Young's modulus and SEM.

Modification of calcium carbonate particles with surfactant significantly improves the properties of polyvinyl chloride (PVC). Hydrophobic spherical CaCO3 particles were prepared in the presence of dodecyl dihydrogen phosphate (DDP) by a carbonation method. In the process, DDP was used as an organic substrate to induce the nucleation and growth of calcium carbonate. The operating parameters such as temperature and the dosage of the organic substrate were varied to study their influences on the active ratio and contact angle of calcium carbonate particles. The surface property of CaCO3 particles was changed from hydrophilic to hydrophobic when the dosage of DDP to CaCO3 changed from 0 to 2%. The contact angle of modified CaCO3 particles was 119.51°. Moreover, X-ray diffraction (XRD), FT-IR spectrums and thermogravimetry analysis (TGA) were employed to characterize the obtained products. The schematic illustration for interaction between the organic substrate and inorganic mineral in aqueous medium was showed in the end. The synthesized CaCO3 was applied to polyvinyl chloride (PVC) to improve its mechanical properties. The properties of PVC/CaCO3 composites have been tested such as tensile strength, impact strength, Young's modulus and SEM.

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