Electrospinning of Ethylene Vinyl Acetate/Carbon Nanotube Nanocomposite Fibers.

Mária Omastová,Eliška Číková,Matej Mičušík

doi:10.3390/polym11030550

Mária Omastová, Eliška Číková + Show 1 more

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https://doi.org/10.3390/polym11030550

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Journal: Polymers	Publication Date: Mar 22, 2019
Citations: 17	License type: CC BY 4.0

Affiliation: Polymer Institute, Slovak Academy of Sciences

Abstract

Nanocomposites, based on an ethylene vinyl acetate (EVA) copolymer with a vinyl acetate content of 34 wt % and varying amounts of multiwall carbon nanotubes (MWCNTs), were prepared by an electrospinning method. The dispersibility of the MWCNTs in the solution was improved by using cholesteryl 1-pyrenecarboxylate (PyChol) as a compatibilizer. The transmission electron microscopy images showed that the MWCNTs were aligned inside of the elastomeric matrix by the electrospinning process. The morphologies of the fibers were evaluated by scanning electron microscopy. When the amount of MWCNTs in the polymer solution reached 3 wt %, fibers with a diameter of 846 ± 447 nm were prepared. The chemical composition of the prepared fibers was investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR results confirmed the presence of a carboxyl group, originating from the presence of PyChol. XPS results showed that the EVA fibers produced by electrospinning were oxidized in ethylene units, when comparing the spectra of the original EVA granules, but the presence of MWCNTs enhanced the stability of the EVA. The thermal stabilities of the fibers were tested with thermogravimetric analysis. The results confirmed that the presence of MWCNTs inside the fibers enhanced the thermal stabilities of the prepared nanocomposites.

Highlights

Ethylene vinyl acetate (EVA), a semicrystalline copolymer, is a flexible and corrosion-resistant material
The conductivities of the electrospun EVA/multiwall carbon nanotubes (MWCNTs) mats were tested by the two-probe method, but since the MWCNTs are coated by the EVA, and their amount is below the percolation threshold, the conductivities were in the range of pure EVA, approximately 10−9 S/cm
A homogenous dispersion of the MWCNTs are coated by the EVA, and their amount is below the percolation threshold, the in the polymer solution was obtained, due to the addition of PyChol as a compatibilizer

Summary

Introduction

Ethylene vinyl acetate (EVA), a semicrystalline copolymer, is a flexible and corrosion-resistant material. EVA is an inexpensive and convenient polymer with a variety of properties that highly depend on the ratio of the ethylene and vinyl acetate units [1]. The polyethylene units dominate the structure of EVA copolymers, and they are partially crystalline, while the amorphous vinyl acetate units are flexible, soft and polar. EVA with 10 wt % of VA exhibits lower water absorptivity and higher tensile strength, permeability, Young’s modulus, and dielectric strength values than EVA with 25 wt % or more of vinyl acetate (VAc) [2]. An increase in the VAc content decreases the tensile strength, resistance to heat deformation, and barrier properties of the copolymer. EVA with 33 wt % of VA is used in cable sheaths, hoses, sheeting, ring seals, etc

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