Selective location of kaolin and effects of maleic anhydride in kaolin/poly(ε-caprolactone)/poly(lactic acid) composites

In the present work, maleic anhydride (MA) and biphenyl peroxide (BPO) were used in the preparation of kaolin (K)/poly(ε-caprolactone) (PCL)/poly(lactic acid) (PLA) composites with melt compounding method. Composition and structure of the composites were characterized by Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). Mechanical properties and thermal behaviors of the composites were further investigated. Kaolin selectively located in poly(ε-caprolactone) domains and at the phase boundaries, which improved the mechanical properties of the composites due to their rigid structure and high modulus. Influences of maleic anhydride on dispersion state of kaolin and two-phase structure of the composites were explored and discussed. Maleic anhydride enhanced the interactions among kaolin, poly(lactic acid) and poly(ε-caprolactone). Meanwhile, it improved the dispersion state of kaolin in the composites. In the presence of both kaolin and maleic anhydride, tensile strength at room temperature and storage modulus at 40 °C were enhanced to 41.2 MPa and 3.9 GPa, respectively.