Pressure‐induced crystallization of low density polyethylene on carbon nanotubes and carbon nanofibers

Abstract

In this study, low‐density polyethylene (LDPE) crystalline structures produced via a solution‐crystallization method on carbon nano‐fillers were characterized. The nano‐fillers used in this study are carbon nanotubes (CNTs) and carbon nanofibers (CNFs). CNTs and CNFs were used to act as a nucleating surface for polymer crystallization. In the case of CNTs, we obtained nanohybrid shish‐kebab architecture by epitaxial crystallization. This is a unique way to bond polymer with nanofillers, in which the CNTs act as shish, while polymer act as kebabs. A pressure‐induced crystallization approach was employed to investigate the effects of crystallization time and pressure on the CNFs/LDPE nanohybrid structure and percent crystallinity. The morphology of the nanohybrids was characterized by scanning electron microscopy (SEM), while differential scanning calorimetry (DSC) was used to quantify the amount of crystalline polymer. The LDPE crystals grown on CNTs had significant morphological differences from those grown on CNFs. The polymer crystals were found to periodically decorate the CNTs with a nanohybrid shish‐kebab (NHSK) architecture, in which CNTs acts as a shish, while LDPE crystals were arranged as circular disks on the CNTs. POLYM. COMPOS., 39:192–200, 2018. © 2016 Society of Plastics Engineers

Influence of graphene nanoscrolls on the crystallization behavior and nano‐mechanical properties of polylactic acid

“…Fundamentally, crystallization involves two stages: nucleation and crystal growth. In our continuous efforts to realize the potential of CNTs to induce polymer crystallization, we found that carbon‐based nanoparticles are effective agents that facilitate nucleation; however, the second stage of growth is governed by space …”

“…In our continuous efforts to realize the potential of CNTs to induce polymer crystallization, we found that carbon-based nanoparticles are effective agents that facilitate nucleation; however, the second stage of growth is governed by space. [31][32][33][34] It has been previously reported that the dimensionality of carbon nanoparticles primarily governs the supramolecular architecture of the crystallized polymer. 24,35 As seen in SEM images of PLA-GNS, the polymer seems to be crystallized randomly on the surface of GNS in multiple orientations to generate a flower-like, petal-shaped structure.…”

Enhanced mechanical, conductivity, and dielectric characteristics of ethylene vinyl acetate copolymer composite filled with carbon nanotubes

“…Some authors also report the decrease in the crystallinity of polyolefins after reinforcing with CNT 37 ; however, others report no changes in the crystallinity. 38 There are also publications that show evidence of the increase of crystallinity of a polymer after CNTs addition, for example, in composites of PE/CNT 39 and PP/CNT. 37 CNT addition to EVA forms the interphase with hindered chain mobility that may efficiently disrupt the crystals’ nucleation and growth in the composite as compared with the neat EVA.…”

Crystallization kinetics of high‐density and low‐density polyethylene on carbon nanotubes

“…[29] During this crystallization process, the periodic growth of lamellar disk-shaped polymer crystals is governed by soft epitaxy where the nanoparticle surface acts as a nucleating agent. [30][31][32] Notably, although the concentration of CNTs is nearly 15 times higher (~20 wt% of polymer) than those reported previously, [33,34] the NHSK architecture is still uniform. The high magnification SEM and TEM images in Figure 2 illustrated that the periodic crystallization of PE on the tube axis of CNTs prevented the agglomeration of CNTs in polymer matrices.…”