Morphological Transformation in Polymer Composite Materials Filled with Carbon Nanoparticles: Part 1—SEM and XRD Investigations

Abstract

HDPE-based nanocomposite fibers have been extruded from a melt and drawn up to draw ratio DR = 8. Two kinds of carbon nanodiscs (original ones and those exposed to additional annealing) have been used as fillers. Obtained nanocomposite fibers have been investigated with the help of different experimental methods: rheology, SEM and WAXS. It has been demonstrated that the annealed carbon nanodiscs possess a nucleation ability that finally leads to strong transformation of the material morphology.

Morphological Transformation in Polymer Composite Materials Filled with Carbon Nanoparticles: Part 2—Thermal and Mechanical Properties

“…At the same time, it should be noted that the original nanodiscs (oND) do not possess such ability with respect to HDPE. All this is additional confirmation for the WAXS data reported in [ 1 ] that the aND fillers are capable of a change in the predominant orientation (texture) of the crystalline regions of the polymer.…”

“…This fact indicates that the aND nanoparticles facilitate and accelerate the crystallization process of the HDPE matrix located around them. In other words, this type of the nanodisc exhibits nucleating ability, which further leads to the formation of transcrystalline polymer regions around them that were already revealed by scanning electron microscopy (SEM) and discussed earlier [ 1 ]. At the same time, it should be noted that the original nanodiscs (oND) do not possess such ability with respect to HDPE.…”

“…At the same time, the greater the number of the introduced aND nanoparticles is, the more transcrystallites adjoin them with their side faces, while the cohesive interaction between the elements of the polymer chains decreases. Consequently, in view of the low adhesion between the nanofiller and the HDPE matrix [ 1 ], it will be easier for such transcrystallites to turn along the orientation axis during the orientational drawing process following the unfolding of their chain folds. All this will undoubtedly affect the quality of the resulting fibrillar structure and further contribute to the increase in the strength of these fibers after orientation drawing (compared to the pure HDPE).…”

“…In the composite fibers containing the oND nanoparticles, the texture of the crystalline regions in the matrix did not change compared to the pure polymer (the A-texture predominates, which is the most convenient for further unfolding of the macromolecular chain folds and transformation of the lamellae into the fibrils) [ 1 ]. However, for the concentration of these nanofillers more than 5 wt.%, the temperature T am decreases only by ~7 °C (compared to the pure HDPE).…”

“…The present work is a continuation of the research of the melt-extruded composite HDPE-based fibers filled with carbon nanoparticles in a shape of nanodiscs, namely, original (oND) and annealed (aND) ones [ 1 ]. It was revealed that both types of the nanoparticles can be well dispersed in the HDPE matrix and aligned along the extrusion direction of the composite fibers.…”