Superior Reinforcement in Melt-Spun Polyethylene/Multiwalled Carbon Nanotube Fiber through Formation of a Shish-Kebab Structure

Abstract

The formation of a shish kebab (SK) structure, where carbon nanotubes (CNTs) serve as shish and polymer lamellae serve as kebab, is particularly interesting and provides a novel way to enhance the polymer-CNT interface. A fine SK structure is achieved through melt spinning. High density polyethylene and pristine CNTs were first compounded in an extruder. The compound was then spun into fibers with different draw ratios with the aid of a capillary rheometer. The crystalline structure and mechanical behavior were characterized by scanning electron microscopy, differential scanning calorimetry, two-dimensional wide-angle X-ray scattering, polarized Raman spectroscopy, and tensile testing. An increase in tensile strength as high as 3 times has been achieved in the fiber. The formation of SKs is considered as the main mechanism responsible for the enhanced interfacial interaction and excellent tensile property.

Formation of a large‐scale shish‐kebab structure of polyoxymethylene in the melt spinning and the crystalline morphology evolution after hot stretching

“…This shish-kebab structure is different from those reported in literature [27,[30][31][32][33][34][35][40][41][42] in terms of pure polymers (PE, PP, and PLA) [27,30,[40][41][42] and polymer/inorganic composites (PE/CNT, PE/inorganic whisker). [28,29] The diameter of a conventional kebab structure is from 0.5 μm to 5 μm, whereas the diameter of the kebab in the present study is 10.5 μm. Thus, we define this type of shish kebab in the melt spinning POM fiber as a large-scale shish-kebab structure.…”

“…[25,26] Pennings first discovered the shish-kebab structure in a polyethylene (PE) solution in 1965; the structure was then intensively investigated in other polymers, compounds, and composites. [27][28][29][30][31][32][33][34][35] For decades, the shear or flow field has been confirmed to induce a shish-kebab morphology and enhance crystallization. [27,28,36] The shish-kebab consists of a single extended-chain central fibrillar core (termed "shish") formed from a single-crystal structure, mesomorphic phase, or single-aligned chain and an assembly of folded-chain crystalline lamellae (termed "kebabs") oriented perpendicularly to the shish.…”

“…[27][28][29][30][31][32][33][34][35] For decades, the shear or flow field has been confirmed to induce a shish-kebab morphology and enhance crystallization. [27,28,36] The shish-kebab consists of a single extended-chain central fibrillar core (termed "shish") formed from a single-crystal structure, mesomorphic phase, or single-aligned chain and an assembly of folded-chain crystalline lamellae (termed "kebabs") oriented perpendicularly to the shish. [29,37] The formation of the shish-kebab structure in the dilute polymer solution under extensional flow can be best explained by using the theory of coil-stretch transition in the polymer solution proposed by Pennings.…”

A Shish-kebab superstructure in low-crystallinity elastomer nanocomposites: Morphology regulation and load-transfer

“…As is well-known, low melt viscosity at high temperature is advantageous for crystal growth, so a higher T c,peak always indicates thicker lamellae, and thus higher T m . 50 Other reason that contributes to higher T m of nanocomposites could be interfacial crystallization of OBC crystals on the surface of CNTBs that made crystals in OBC nanocomposites more thermally stable. The T m of OBC nanocomposites decreases when filler content is beyond 1 wt% because confined space brought by overabundant CNTBs can eliminate crystal maturation.…”

Reinforcing polyamide 1212 with graphene oxide via a two-step melt compounding process

“…Nanofillers exhibit heterogeneous nucleation effect in a polymer matrix [22,23]. Polymer chains epitaxially crystallize on nanofiller surfaces [24,25], and polymer chain relaxation is hindered [26,27]. Therefore, the alignment effect of GO nanosheets on the composites' mechanical properties is of particular interest.…”