Interfacial characteristics of poly(ε‐caprolactone)‐grafted‐halloysites nanotubes bionanocomposites

Abstract

Dielectric and thermal characterization of nanohybrid films based on poly(ε‐caprolactone) biopolymer were investigated. Nano‐composites samples with distinct loadings of halloysite nanotubes (HNT) were prepared by in situ Ring Opening Polymerisation of ε‐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°C to 50°C. The BDS measurements revealed four significant dielectric processes α‐primary relaxation attributed to glass transition, β‐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.

Study of the dynamic fragility of polymer nanocomposites: Correlation with damping

“…The addition of CNTs may lead to a higher fragility for a polyazomethine nanocomposite, 21 while the incorporation of POSS particles in an epoxy resin causes a reduced fragility, indicating the development of a stronger and more homogeneous structure 18 . On the other hand, it is reported in reference 11 that the fragility does not change in the case of poly(ε‐caprolactone) biopolymer reinforced with distinct loadings of halloysite nanotubes.…”

“…Within this context, secondary relaxations, T g , dynamic fragility, and activation energy of polymers and polymer nanocomposites were investigated. [6][7][8][9][10][11] The fragility parameter, is also considered to be helpful in analyzing the degree of heterogeneity at different amorphous materials, [12][13][14][15] whereas in reference 16 the fracture toughness of the silica particle/epoxy composites was apparently dependent on fragility.…”

“…Within this context, secondary relaxations, T g , dynamic fragility, and activation energy of polymers and polymer nanocomposites were investigated 6–11 …”

Molecular dynamics of poly(ε‐caprolactone)/beidellite organoclay bionanocomposites obtained by in‐situ polymerization highlighted by dielectric relaxation spectroscopy

“…Instead, the results suggested a dominant process tied to the accumulation of charges at boundaries within the crystalline phase. This relaxation phenomenon is recognized as Maxwell–Wagner–Sillars (MWS) polarization and has been previously discussed in multiple studies concerning PCL's dielectric properties 9,44–46 . The MWS polarization is a characteristic behavior of heterogeneous materials, where free charges accumulate at the interfaces of subphases exhibiting nonidentical conductivity.…”

Evolution of dielectric properties of Kevlar/epoxy laminated composites after hybridization by naturally woven Coco Nucifera sheaths

“…Such a parameter quantifies the density, the dipolar moment and the interconnection of dipoles that aggregate then obstruct at fiber/matrix interfaces, contributing to the MWS polarization. 44 ∆εMWS values of laminated hybrid composites at temperatures varying from 150°C to 170°C are listed in Table 3.…”