The formation of a nanohybrid shish-kebab (NHSK) structure in melt-processed composites of poly(ethylene terephthalate) (PET) and multi-walled carbon nanotubes (MWCNTs)

Abstract

. (2017) The formation of a nanohybrid shish-kebab (NHSK) structure in meltprocessed composites of poly (ethylene terephthalate) (PET) and multiwalled carbon nanotubes (MWCNTs). Polymer, 117. pp. 208-219. Permanent WRAP URL:http://wrap.warwick.ac.uk/87613 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL' above for details on accessing the published version and note that access may require a subscription. KeywordsPolymer-MWCNT nanocomposites, crystalline morphology, kinetics, small-and wide-angle X-ray scattering (SAXS/WAXS), nanohybrid shish-kebab structure (NHSK) AbstractThe combination of synchrotron Small-and Wide-Angle X-ray scattering (SAXS/WAXS), and thermal analysis was used to follow the evolution of crystalline morphology and crystallization kinetics in a series of melt-processed composites of poly(ethylene terephthalate) (PET) and multiwall carbon nanotubes (MWCNT). The as-extruded PET-MWCNT composites underwent both hot and cold isothermal crystallizations where a final oriented nanohybrid shish-kebab (NHSK) crystalline structure was observed. An oriented NHSK structure was seen to persist even after melting and recrystallization of the composites.From the scattering data, we propose a model whereby the oriented MWCNTs act as heterogeneous nucleation surfaces (shish) and the polymer chains wrap around them and the crystallites (kebabs) grow epitaxially outwards during crystallization. However, depending on crystallization temperature, unoriented crystallites also grow in the polymer matrix, resulting in a combination of a NHSK and lamellar morphology. In contrast, the neat PET homopolymer showed the sporadic nucleation of a classic unoriented lamellar structure under the same isothermal crystallization conditions. These results provide a valuable insight into -2 -the distinctive modification of the crystalline morphology of melt-processed polymer-MWCNT composites prior to any secondary processing, having a significant impact on the use of MWCNTs as fillers in the processing and modification of the physical and mechanical properties of engineering polymers.

Mechanical Properties of Polyethylene‐Carbon Nanotube Composites Synthesized by In Situ Polymerization Using Metallocene Catalysts

“…Results of stress-strain measurements are also summarized in Table 1. In contrary to the reports, on enhancement in mechanical properties for CNT-lled polyole n prepared by melt mixing [25][26][27], a fall in the mechanical properties was found for the polyethylene nanocomposites prepared by the stirring method.…”

“…ere is no uniform "shish-kebab" morphology like our previous report [20], but it is evident that CNT is coated by PE which might restrict chain mobility. Recently, a shish-kebab nanohybrid structure was reported for polyethylene terephthalate-MWCNT composites by the melt-processing method [26]. e variation in the storage modulus with temperature was studied as shown in Figure 3 for neat PE and the polymer nanocomposite.…”

Plasticisation and compatibilisation of poly(propylene) with poly(lauryl acrylate) surface modified MWCNTs

“…CNT-induced polymer crystallisation can create nano-hybrid shish-kebab structures, induce the formation of different crystal polymorphs and alter significantly crystallisation kinetics. [34][35][36] Therefore, it is important to characterise changes in crystal structure and morphology when incorporating CNTs into polymer melts. [22] Additionally, reports have suggested modification of MWCNTs can lead to the formation of the β-polymorph of PP which leads to weaker mechanical properties and such behaviour can be studied using WAXD, [37] and scattering techniques (WAXS/SAXS).…”

Crystallization and Thermal Behaviors of Poly(ethylene terephthalate)/Bisphenols Complexes through Melt Post-Polycondensation

“…Several efforts have been made to regulate the crystallization rate of PET by inclusion of nanofillers [17,18]. Some authors found that SiO 2 nanoparticles [19,20], modified graphene oxide [21], multiwalled carbon nanotubes [22,23], polyhedral oligomeric silsesquioxanes [24,25] and calcium carbonate [26] could act as a heterogeneous nucleating agent and increase the crystallinity of PET.…”