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Gargiuli JF, Quino G, Board R, Griffith JC, Shaffer MSP, Trask RS, Hamerton I. Examining the Quasi-Static Uniaxial Compressive Behaviour of Commercial High-Performance Epoxy Matrices. Polymers (Basel) 2023; 15:4022. [PMID: 37836071 PMCID: PMC10574947 DOI: 10.3390/polym15194022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/14/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023] Open
Abstract
Four commercial high-performance aerospace aromatic epoxy matrices, CYCOM®890, CYCOM®977-2, PR520, and PRISM EP2400, were cured to a standardised 2 h, 180 °C cure cycle and evaluated in quasi-static uniaxial compression, as well as by dynamic scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermoplastic toughened CYCOM®977-2 formulation displayed an overall increase in true axial stress values across the entire stress-strain curve relative to the baseline CYCOM®890 sample. The particle-toughened PR520 sample exhibited an overall decrease in true axial stress values past the yield point of the material. The PRISM EP2400 resin, with combined toughening agents, led to true axial stress values across the entire plastic region of the stress-strain curve, which were in line with the stress values observed with the CYCOM®890 material. Interestingly, for all formulations, the dilation angles (associated with the volume change during plastic deformation), recorded at 0.3 plastic strain, were close to 0°, with the variations reflecting the polymer structure. Compression data collected for this series of commercial epoxy resins are in broad agreement with a selection of model epoxy resins based on di- and tetra-functional monomers, cured with polyamines or dicarboxylic anhydrides. However, the fully formulated resins demonstrate a significantly higher compressive modulus than the model resins, albeit at the expense of yield stress.
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Affiliation(s)
- J. F. Gargiuli
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
| | - G. Quino
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
- Department of Aeronautics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - R. Board
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
| | - J. C. Griffith
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
| | - M. S. P. Shaffer
- Department of Materials and Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK;
| | - R. S. Trask
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
| | - I. Hamerton
- Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, Faculty of Science and Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; (J.F.G.); (G.Q.); (R.B.); (J.C.G.); (R.S.T.)
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Abstract
Graphene is a good candidate for protective material owing to its extremely high stiffness and high strength-to-weight ratio. However, the impact performance of twisted bilayer graphene is still obscure. Herein we have investigated the ballistic resistance capacity of twisted bilayer graphene compared to that of AA-stacked bilayer graphene using molecular dynamic simulations. The energy propagation processes are identical, while the ballistic resistance capacity of the twisted bilayer graphene is almost two times larger than the AA-bilayer graphene. The enhanced capacity of the twisted bilayer graphene is assumed to be caused by the mismatch between the two sheets of graphene, which results in earlier fracture of the first graphene layer and reduces the possibility of penetration.
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