Polymer Engineering and Science, Vol.61, No.2, 397-409, 2021
Interfacial characteristics of poly(epsilon-caprolactone)-grafted-halloysites nanotubes bionanocomposites
Dielectric and thermal characterization of nanohybrid films based on poly(epsilon-caprolactone) biopolymer were investigated. Nano-composites samples with distinct loadings of halloysite nanotubes (HNT) were prepared by in situ Ring Opening Polymerisation of epsilon-caprolactone. The effect of the incorporated HNT on the molecular relaxation process and interfacial polarization of PCL was studied via broadband dielectric spectroscopy (BDS) on a frequency domain starting from 1E-1 to 1E6 Hz and at temperatures ranging from -70 degrees C to 50 degrees C. The BDS measurements revealed four significant dielectric processes alpha-primary relaxation attributed to glass transition, beta-secondary relaxation and two interfacial polarizations due to the semi-crystalline character of PCL and the added HNT fillers. According to our results, the weight ratio of HNT ranging between 3% and 5% is recommended for achieving the highest performing nanocomposite that can be used in several applications.
Keywords:dielectric relaxation;interfacial polarization;nanocomposites;natural fibers;thermal properties