Thermo-mechanical characterization of electrospun polyurethane/carbon-nanotubes nanofibers: a comparative study

Abstract

Creating ultrathin, mountable fibers from a wide range of polymeric functional materials has made electrospinning an adequate approach to producing highly flexible and elastic materials. In this paper, electrospinning was utilized to produce thermoplastic polyurethane (TPU) nanofibrous membranes for the purpose of studying their thermal and mechanical properties. Towards a study of the effects of fiber orientation and multi-walled carbon nanotubes (MWCNTs) as a filler on both mechanical and thermal characteristics of electrospun TPU mats, an experimental comparison was held between unidirectional and randomly aligned TPU and TPU/MWCNTs nanofibrous structures. The incorporation of MWCNTs into randomly oriented TPU nanofibers resulted in a significant increase in Young's modulus (E), from 3.9 to 7.5 MPa. On the other hand, for unidirectionally spun fibers, Young's modulus increased from 17.1 to 18.4 MPa upon the addition of MWCNTs. However, dynamic mechanical analysis revealed a different behavior. The randomly oriented specimens exhibited a storage modulus with a significant increase from 180 to 614 MPa for TPU and TPU/MWCNTs mats, respectively, and a slight increase from 119 to 143 MPa for unidirectional TPU and TPU/MWCNTs mats, respectively. Meanwhile, the loss modulus increased with the addition of MWCNTs from 15.7 to 58.9 MPa and from 6.4 to 12 MPa for the random and aligned fibers, respectively. The glass transition values for all the mats fell in the temperature range of – 60 to − 20 °C. The thermal degradation of the membranes was not significantly affected by the addition of MWCNTs, indicating that the mixing of the two constituents did not change the TPU’s polymer structure and that the TPU/MWCNTs nanocomposite exhibited stable thermal degradation properties.

Fabrication of in situ polymerized polyaniline‐based functional nanofibrous structures for flexible electromechanical devices

“…The XRD spectra of aligned TPU, TPU/PANI, and TPU/MWCNTs/ PANI nanofibrous mats are displayed in Figure 5A. According to the literature, pure TPU mats have a broad peak at approximately 2Ө = 20 , while for MWCNTs, there is a diffraction peak at 2Ө = 26.03 , 25,34 and the PANI polymer has two diffraction peaks around 20.4 and 26.28 . 33 The XRD spectrum for TPU/PANI mat reveals two peaks at 2Ө akin to PANI.…”

“…In continuation of the authors' previous work, 25 The solutions were electrospun using NANON-01B setup (MECC CO., Ltd Japan), with a dehumidification system to prevent bead formation, to create random and aligned fibrous membranes.…”

“…This is clearly illustrated in the authors' previous work. 25 The maximum strain reached by the membranes was recorded during the testing, while tensile stress (σ) was determined using Mass-based normalization according to Equation 1, 28…”