Study of matrix-filler interaction of polypropylene/silica composite by combined infrared (IR) spectroscopic imaging and disrelation mapping

We demonstrate a Fourier transform infrared (FTIR) spectroscopic imaging combined with two-dimensional (2D) correlation analysis to elucidate matrix-filler interaction of polymer composites. Composite of maleic anhydride grafted polypropylene (MAPP) and silica sphere (SS) was fabricated. The FTIR image and disrelation map derived from sets of FTIR spectra suggest that the maleic anhydride groups in MAPP surround the SS surface and interact with the silanol on the surfaces of SS via hydrogen bonding. This clear link between MAPP and SS indicates that MAPP can be utilized as a suitable amphiphilic compatibilizer for an SS filler when it is mixed with hydrophobic polymer. FTIR imaging analysis was then further extended to categorize the interfacial states of more complicated polymer composites consisting of polypropylene (PP)/SS containing MAPP as a compatibilizer. Probing the interfacial chemical state using FTIR imaging revealed the interaction between MAPP and SS to contribute to improved elastic modulus of PP/MAPP/SS.