No abstract

In the present work, the thermomechanical performance of linear low‐density polyethylene (LDPE) reinforced with multi‐walled carbon nanotubes (CNTs) is investigated by means of scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile and electrical testing. The ball milling and melt mixing procedure, employed for the nanocomposites preparation provided improvement of the thermomechanical properties. The findings are encouraging for a wider application of linear LDPE. The nanocomposites’ elastic behaviour was further described by three different micromechanics models. It was found that the model based on the effective continuum fiber was capable of describing the Young's modulus for all CNTs concentrations, revealing also the micromorphology and the dispersion quality of the nanocomposites examined. POLYM. COMPOS., 39:E1118–E1128, 2018. © 2017 Society of Plastics Engineers

In the present research, a series of hybrid nanocomposites based on polylactic acid (PLA) matrix and mixtures of graphene oxide (GO) with carbon nanotubes (CNTs) or carbon nanofibers (CNFs), at various loadings, were prepared and experimentally studied. Several experimental techniques were employed to analyze the morphology and the thermomechanical performance of the materials, as well as the dielectric properties. The related experimental data support the conclusion that a synergistic effect is exhibited by the PLA/GO/CNT nanocomposites. This effect was verified by the higher mechanical enhancement, the higher crystallinity and the development of conductive paths into the bulk matrix.

Nanocomposites, based on a metallocene linear low‐density polyethylene matrix (mLLDPE), reinforced with multiwalled carbon nanotubes (CNTs), at various CNT loadings, have been prepared and studied by scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile‐electrical testing, and Raman spectroscopy. The melt‐mixing procedure has been applied to prepare the nanocomposites, whereas the polyethylene matrix type (mLLDPE) employed was proved to be decisive in producing nanocomposites with improved thermomechanical/electrical properties, due to a good quality dispersion of the CNTs into the specific bulk matrix. Moreover, the electrical conductivity obtained at a specific CNT loading was analyzed by a model relating the electrical resistance of the CNT/nanocomposites with the effective length of CNTs, and the thickness of the interphase between matrix and CNTs. These quantities are parameters which participate in the tunnel effect. The simulated parameter values were in accordance with the results of the micromechanics modeling. POLYM. COMPOS., 40:E1263–E1273, 2019. © 2018 Society of Plastics Engineers

In the present work, the creep response of nanocomposites based on metallocene linear low density polyethylene (mLLDPE), reinforced with three types of carbonaceous nanofillers, namely carbon nanotubes (CNTs), graphene oxide (GO) platelets, and carbon nanofibers (CNFs) was experimentally studied. The effect of the nanofiller loading and the hybrid character of nanocomposites on the creep resistance of the nanocompsites was analyzed. In all cases, the creep resistance of the nanocomposites examined has been postulated. To support these results, creep has been modeled by a power creep law, while the creeprecovery modeling was achieved by a viscoelastic model. The implementation of the viscoelastic model has been made by assuming that the nanocomposite's structure can be represented by a physical network, with the dispersed nanofillers participating in the molecular rearrangements, which take place upon the imposition of stress. The time dependent constitutive equation involves a relaxation function, based on a Gaussian type distribution function, associated with the energy barriers that molecular segments need to overcome, for transitions to occur. It was found that creep-recovery strain could be accurately captured with the same set of parameters, whereas the number of required model parameters was quite lower than that in the widely known viscoelastic models.