Diameter dependence of hybrid shish‐kebab structure in polyethylene/carbon material fiber composites

Abstract

PE chains can proceed template crystal growth on multi‐walled carbon nanotubes (MWCNTs) surface and develop into hybrid shish‐kebab (HSK) abiding by the “soft epitaxy” mechanism. For large‐diameter carbon nanofiber (CNF), the lattice matching and epitaxy are the main mechanism for hybrid structure formation under the static state. This study provided a new understanding of HSK formation, wherein PE underlay on the surface of carbon material fiber played an important role. The shear flow induced PE chains to orient along the CNF surface and formed PE underlayer. Subsequently, ordered subglobules were periodically formed along the CNF axis and finally evolved to typical HSK structures with well‐aligned arraying PE lamellae rather than random one. As the diameter increased to 7000 nm, even though the graphite (002) planes in carbon fibers (CFs) was similar to that in CNFs, the attractive van der Waals interactions between CFs and PE chains were too weak to drive enough PE chains to absorb on the CFs surface and form PE underlay even under the shear flow, leading to the absence of PE lamellae on the CF surface. Based on that, the “soft epitaxy” could be the main formation mechanism of HSK structures for carbon material fibers regardless of their diameters. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 297–303

Polymer Crystallization on One-Dimensional Templates: From a Hybrid Shish-Kebab-like Structure to Material Properties

“…In this case, the CNT acts as a rigid macromolecular scaffold, and PE chains are adsorbed onto the surface and then aligned parallel along the tube axis regardless of the CNT chirality, which is named “size-dependent soft epitaxy”. This mechanism was confirmed in the work of Xia et al by using MWNTs, nanofibers, and carbon fibers with varying diameters …”

“…This mechanism was confirmed in the work of Xia et al by using MWNTs, nanofibers, and carbon fibers with varying diameters. 45 The matrix can also be extended to copolymers or other end modified materials to achieve the functional modification purpose of CNTs. 33 Li et al 14 used PE-b-PEO copolymers instead of PE to decorate SWNTs by a solution crystallization method.…”

Surface Functionality through Periodical Patterning on Carbon Nanotubes

“…Xia et al [105] used different carbon fibrous precursors (CNTs [20-30 nm], carbon nanofibers (CNFs) [100-150 nm], and carbon fibers (CFs) [7000 nm]) to study the effect of fiber diameter on [48] Reproduced with permission. [48] Copyright 2017, Elsevier.…”

“…For example, the periodic structure of PE-b-PEO has been obtained in 1,2-dichlorobenzene (DCB) or p-xylene as selective solvents for PE segments. However, the periodic patterned [105] Reproduced with permission. [105] Copyright 2017, Wiley-VCH.…”

“…However, the periodic patterned [105] Reproduced with permission. [105] Copyright 2017, Wiley-VCH. structure was not observed in N,N-dimethylacetamide (DMAc) as a selective solvent for PEO segments.…”