Polyurea/Aminopropyl Isobutyl Polyhedral Oligomeric Silsesquioxane-Functionalized Graphene Nanoplatelet Nanocomposites for Force Protection Applications

Mohammad Mansourian-Tabaei; Mohammed Majdoub; Dineshkumar Sengottuvelu; Damian L Stoddard; Rooban V K G Thirumalai; Mine G Ucak-Astarlioglu; Ahmed Al-Ostaz; Sasan Nouranian

doi:10.1021/acsami.4c02244

Polyurea/Aminopropyl Isobutyl Polyhedral Oligomeric Silsesquioxane-Functionalized Graphene Nanoplatelet Nanocomposites for Force Protection Applications

ACS Appl Mater Interfaces. 2024 Apr 17;16(15):19625-19641. doi: 10.1021/acsami.4c02244. Epub 2024 Apr 8.

Authors

Affiliations

¹ Department of Chemical Engineering, University of Mississippi, University, Mississippi 38677, United States.
² Center for Graphene Research and Innovation, University of Mississippi, University, Mississippi 38677, United States.
³ Department of Mechanical Engineering, University of Mississippi, University, Mississippi 38677, United States.
⁴ Institute for Imaging and Analytical Technologies, Mississippi State University, Mississippi State, Mississippi 39762, United States.
⁵ Geotechnical and Structures Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi 39180-6199, United States.
⁶ Department of Civil Engineering, University of Mississippi, University, Mississippi 38677, United States.

PMID: 38588400
DOI: 10.1021/acsami.4c02244

Abstract

Herein, the development of new nanocomposite systems is reported based on one-part polyurea (PU) and aminopropyl isobutyl polyhedral oligomeric silsesquioxane (POSS)-functionalized graphene nanoplatelets (GNP-POSS) as compatible nanoreinforcements with the PU resin. GNP-POSS was effectively synthesized via a two-step synthesis protocol, including ultrasonication-assisted reaction and precipitation, and carefully characterized with respect to its chemical and crystalline structure, morphology, and thermal stability. FTIR and XPS spectroscopy analyses revealed that POSS interacts with the residual oxygen moieties of the GNPs through both covalent and noncovalent bonding. The X-ray diffraction pattern of GNP-POSS further revealed that the crystallinity of the GNPs was not altered after their functionalization with POSS. GNP-POSS was successfully incorporated in PU at contents of 1, 3, 5, and 10 wt % to yield PU/GNP-POSS nanocomposite films. An ATR-FTIR analysis of these films confirmed the presence of strong interfacial interactions between the urea groups of PU and the GNP-POSS functionalities. Moreover, the PU/GNP-POSS nanocomposite films exhibited enhanced thermal stability and mechanical properties compared to those of the neat PU film. The quasi-static tensile testing of the PU/GNP-POSS samples revealed remarkable enhancements in the tensile strength (from 7.9 for the neat PU to 25.1 MPa for PU/GNP-POSS) and Young's modulus (238-617 MPa), while elongation at break and toughness also showed 14 and 125% improvements, respectively. Finally, the effects of GNP-POSS content on the morphological, quasistatic tensile, and high-strain-rate dynamic behavior of the PU/GNP-POSS nanocomposite films were also investigated. Overall, the tests performed using a split-Hopkinson pressure bar setup revealed a large increase in the film strength (from 147.6 for the neat PU film to 199 MPa for the PU/GNP-POSS film) and a marginal increase in the energy density of the film (38.1-40.8 kJ/m³). These findings support the suitability of the PU/GNP-POSS nanocomposite films for force protection applications.

Keywords: POSS; force protection; graphene nanoplatelets; polyurea; split-Hopkinson pressure bar.