Preparation, characterization, thermal, and electrical properties of chlorinated ethylene propylene diene monomer/hydroxyapatite nanocomposites

Nanocomposites composed of chlorinated ethylene propylene diene monomer rubber (Cl-EPDM) with various contents of hydroxyapatite nanoparticles (HA) were prepared in an open two-roll mixing mill. The effect of nanoparticle concentration on structural, morphological, thermal, and electrical properties were examined by different characterization technique such as Fourier transform infrared spectroscopy (FTIR), UV, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), thermogravimetric analysis (TGA), and impedance analyzer. The shift in the IR and UV absorption frequencies of nanohybrid relative to that of chlorinated EPDM indicated the successful encapsulation of crystalline hydroxyapatite particles in the modified elastomer chain. The X-ray diffraction pattern of the fabricated composite revealed the more ordered arrangement of nanoparticles within the elastomer chains and the amorphous nature of polymer decreases with raise in filler loading. The examination of nanocomposite morphology by SEM showed that the inorganic particles were well dispersed in the organic phases. TGA analysis showed the enhanced thermal stability of the composites with increase in the loading of nanoparticles. Shift in the glass transition temperature to a higher value in DSC thermograms of new hybrid indicated the increased orderness of the Cl-EPDM/HA nanocomposite. The AC electrical conductivity was influenced significantly by the frequency of applied field and the concentration of nanofiller. Dielectric properties strongly distort at lower frequencies but became independent as frequency increased above 10(3) Hz. POLYM. COMPOS., 39:2093-2100, 2018. (c) 2016 Society of Plastics Engineers