New polyurea MWCNTs nanocomposite films with enhanced mechanical properties

Abstract

Polyurea nanocomposites represent a promising option in the development of advanced materials for applications that require high mechanical resistance. This article describes an optimized synthetic route for obtaining polyurea nanocomposites with enhanced mechanical properties by employing epoxy‐functionalized multiwalled carbon nanotubes (MWCNTs) as reinforcing agent. The experimental measurements revealed that these functionalized nanofillers have a positive effect on the properties of the composite only until they reach a certain concentration; therefore, the optimal composition was reported (the samples containing 0.2 weight % functionalized MWCNTs). The functionalization of the MWCNTs was confirmed through RAMAN, X‐ray photoelectron spectroscopy, scanning electron microscopy and thermogravimetric analysis, while the polyurea nanocomposites obtained have been characterized by thermal (differential scanning calorimetry and TGA) and mechanical (dynamic mechanical analysis and tensile tests) analyses. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45061.

High performance aliphatic polyurea films reinforced using nonfunctionalized multiwalled carbon nanotubes

“…It is known that the two main factors such as dispersion of carbon nanomaterials and interfacial interaction of nanomaterials and polymer matrix govern the mechanical properties of the nanocomposite . In this study, the vast improvement in mechanical properties of PUs using MWCNTs agreed with the literatures . Qian et al showed an 80% improvement in tensile strength by adding 0.2 wt% of graphene from 13 to 23.6 MPa, whereas a 71% improvement in Young's modulus was presented in MWCNTs/PU composite by Toader et al at the same concentration.…”

“…Indeed, the MWCNT doping has caused a 5.5 C increase in the decomposition onset temperature which is an indication of increased thermal stability. Toader et al [26] who conducted a similar MWCNT doping of an aromatic PU experienced a similar TGA result reporting that the addition of MWCNTs offered a small but positive impact on the thermal stability of PU. Figure 6 shows the DSC heat flow diagram of both samples.…”

“…[16] In this study, the vast improvement in mechanical properties of PUs using MWCNTs agreed with the literatures. [8,17] Qian et al [8] showed an 80% improvement in tensile strength by adding 0.2 wt% of graphene from 13 to 23.6 MPa, whereas a 71% improvement in Young's modulus was presented in MWCNTs/PU composite by Toader et al [26] at the same concentration. As such, it is possible to assume that ultrasonication in this case is sufficient to greatly disperse the MWCNTs within PU matrix without adapting functionalization approaches.…”

Electroconductive materials based on carbon nanofibers and polyaniline

“…In order to confirm the chemical modification of the CNF, XPS analysis was performed on the two modified CNF. The XPS analysis (Figure ), C1s deconvolution, for the modified CNF confirmed the chemical modification, which is sustained by the change of the C‐C sp 2 percentage and increase in C‐C sp 3 . Also, in the case of AA functionalization, oxygen content of the modified CNF was determined to be 11.95% (atomic %), whereas the in the case of GMA 15.85% (atomic %).…”

“…The XPS analysis (Figure 2), C1s deconvolution, for the modified CNF confirmed the chemical modification, which is sustained by the change of the C-C sp 2 percentage and increase in C-C sp 3 . [18][19][20] Also, in the case of AA functionalization, oxygen content of the modified CNF was determined to be 11.95% (atomic %), whereas the in the case of GMA 15.85% (atomic %). This difference is due to the different oxygen content of the monomers as well as to their different reactivity in radical polymerization.…”