Understanding the impact of plasma functionalized MWCNTs on the structure, physicochemical and mechanical properties of PEMA

Abstract

In this study, plasma functionalized multiwalled carbon nanotubes, f-MWCNTs, were incorporated into a poly(ethyl methacrylate), PEMA, polymer matrix at different wt.% (0.005, 0.01, and 0.02 wt.%) to prepare nanocomposite films using the traditional solution casting method. The XRD, Raman spectroscopy, XPS, TGA, mechanical analysis and UV-Vis spectroscopy techniques were employed to investigate the effects of the wt.% of f-MWCNTs on the structure, spectroscopic and other physiochemical properties of the synthesized films. XRD analysis showed a monotonic change in the PEMA structure upon incorporation of f-MWCNTs at different wt.%. The XPS results showed an increase of oxygen-based functional groups C-O and O-C-O on the PEMA/f-MWCNTs/ composite films compared to pure PEMA. Raman spectroscopy results consistent with the XRD and XPS findings, confirming the homogeneous distribution of f-MWCNTs in the PEMA matrix. Thermal stability of f-MWCNTs/PEMA improved as the f-MWCNTs content increased. Optical studies showed a reduction in the bandgap energy as the f-MWCNTs content increased, accompanied by significant improvements in optical properties such as refractive index (n), extinction coefficient (k), dielectric constants (ε' and ε″), and optical conductivity (σ_opt). Mechanical testing revealed enhancements in breaking strength, Young's modulus, yield stress, and elongation at break with increasing f-MWCNTs concentrations. Furthermore, the AC electrical conductivity of the films also improved, demonstrating better charge transport capabilities. These synergistic enhancements in optical, thermal, mechanical, and electrical properties make PEMA/f-MWCNTs nanocomposites promising candidates for advanced applications, including optoelectronic devices, optical components, and conductive packaging materials.

Keywords: AC conductivity; Mechanical; Optical; PEMA; Thermal stability; f-MWCNTs.

Fig. 1

XRD patterns of (a) neat PEMA, PEMA loaded with various wt.% of f-MWCNTs (b) 0.005%, (c) 0.01% and (d) 0.02%. (e) plasma functionalized-MWCNTs (f-MWCNT).

Fig. 2

Raman spectra of (a) neat PEMA, PEMA loaded with various wt.% of f-MWCNTs (b) 0.005%, (c) 0.01% and (d) 0.02%.

Fig. 3

(a) Survey spectra of pristine PEMA and PEMA/f-MWCNTs samples, (b) C 1s and (c) O 1s of spectra of pristine PEMA sample.

Fig. 4

TGA (a) and DTGA (b) curves for pristine PEMA and PEMA/f-MWCNTs samples.

Fig. 5

The UV/VIS optical (a) absorption, (b) transmittance, and (c) reflectance spectra of PEMA and PEMA/f-MWCNTs composite films.

Fig. 6

Variation of [α E]^0.5 (a) and [α E]² (b) with the energy of photon of neat PEMA and PEMA loaded with various wt.% of f-MWCNTs.

Fig. 7

The extinction coefficient (k) (a) and refractive index (n) (b) against the wavelength for neat PEMA and PEMA loaded with various wt.% of f-MWCNTs.

Fig. 8

The optical conductivity versus the photon energy for neat PEMA and PEMA loaded with various wt.% of f-MWCNTs.

Fig. 9

(a) The real and (b) imaginary parts of dielectric constant for neat PEMA and PEMA loaded with various wt.% of f-MWCNTs.

Fig. 10

Mechanical behavior of pristine PEMA and PEMA doped with different wt.% of f-MWCNTs composite samples at a strain rate of 3.3 × 10^–4 s^-1 and 25 °C. (a) Tensile stress–strain curves tested, (b) Strain-hardening rate as a function of strain, and (c and d) corresponding histogram of ultimate tensile stress UTS, elongation, yield stress YS, and Young Modulus.

Fig. 11

The AC conductivity against the applied frequency for neat PEMA and PEMA loaded with various wt.% of f-MWCNTs.