Preparation of PMMA grafted calcium carbonate whiskers and its reinforcement effect in PVC

In this study, calcium carbonate (CaCO3) whiskers were grafted with poly(methyl methacrylate) (PMMA) by in-situ emulsion polymerization using γ-methacryloxy propyl trimethoxyl silane (γ-MPS) as a coupling agent, and the properties of resultant whisker were determined using Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The results show that PMMA has been successfully grafted onto the surface of CaCO3 whiskers and the maximum grafting degree (Gd) is 3.75%. The scanning electron microscopy (SEM) micrographs of the tensile-fractured surfaces show that modified CaCO3 whiskers have strong interfacial adhesion to the poly(vinyl chloride) (PVC) matrix. The tensile strength increases from 44.0 MPa for PVC composite with unmodified whisker to 49.5 MPa for that with grafted whisker. The dynamic mechanical analysis (DMA) and TGA results indicate that the composites reinforced by modified CaCO3 whiskers have much higher modulus, glass transition temperature, and better thermal stability than their counterparts reinforced by unmodified CaCO3 whiskers. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers