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Ngubane NP, Akiri SO, Omondi B, Ojwach SO. Syntheses of N^O-donor palladium(II) complexes and applications as recyclable catalysts in biphasic methoxycarbonylation of alkenes. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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Akiri SO, Ojwach SO. Sterically hindered (pyridyl)benzamidine palladium(II) complexes: Syntheses, structural studies, and applications as catalysts in the methoxycarbonylation of olefins. Appl Organomet Chem 2021. [DOI: 10.1002/aoc.6439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Saphan O. Akiri
- School of Chemistry and Physics University of KwaZulu‐Natal Pietermaritzburg South Africa
| | - Stephen O. Ojwach
- School of Chemistry and Physics University of KwaZulu‐Natal Pietermaritzburg South Africa
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Akiri SO, Ojwach SO. Structural studies and applications of water soluble (phenoxy)imine palladium(II) complexes as catalysts in biphasic methoxycarbonylation of 1-hexene. J Organomet Chem 2021. [DOI: 10.1016/j.jorganchem.2021.121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ramírez-Soria EH, Bonilla-Cruz J, Flores-Amaro MG, García VJ, Lara-Ceniceros TE, Longoria-Rodríguez FE, Elizondo P, Advincula RC. On the Effect of Ultralow Loading of Microwave-Assisted Bifunctionalized Graphene Oxide in Stereolithographic 3D-Printed Nanocomposites. ACS APPLIED MATERIALS & INTERFACES 2020; 12:49061-49072. [PMID: 33073976 DOI: 10.1021/acsami.0c13702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface functionalization of graphene oxide (GO) is one of the best ways to achieve homogeneous dispersions of GO within polymeric matrices and composites. Nonetheless, studies regarding how the level of GO functionalization affects the macroscopic properties of three-dimensional (3D) printed nanocomposites are still few. Furthermore, the bifunctionalization of GO with the NH2/NH3+ groups to obtain improved thermomechanical macroscopic properties at ultralow loads has not been reported. In this paper, fast and straightforward surface bifunctionalization of GO with a controlled ratio of NH2/NH3+ groups at low, medium, and high functionalization levels (AGOL, AGOM, and AGOH) in a one-step microwave-assisted synthesis is reported for the first time. The functionalization mechanism was disclosed, wherein three graft densities (Gφ) were obtained. A plateau of maximum functionalization (Gφ = 4.9 μmol/m2 = 2.9 molecules/nm2) was reached, suggesting that full coverage of the GO surface is achievable. Also, an increase in the exfoliation of functionalized layers was obtained, ranging from d002 = 8.6 Å up to d002 = 15.8 Å. X-ray photoelectron spectroscopy (XPS) reveals the successful functionalization of GO, as well as an atomic relationship NH2/NH3+ of about 50/50% in all functionalized samples. Stereolithographic (SLA) 3D-printed nanocomposites (AGOL/R, AGOM/R, and AGOH/R) were obtained using ultralow loads (0.01 wt %) of each bifunctionalized material. This ultralow amount was sufficient to enhance thermal stability (up to 4 °C) and a significant increase in the glass transition temperature (93 °C ≤ Tg ≤ 120 °C). Interestingly, we found that low and medium grafting density promotes a ductile material (ε > 5%); meanwhile, a high graft density produces brittle materials. Also, we observe that the toughness can be tuned as a function of the graft density (AGOH: 24 MPa, AGOM: 342 MPa, AGOL: 562 MPa) at ultralow loadings. The 3D-printed nanocomposites using GO with low graft density (AGOL) increase their tensile strain by 90% in comparison with the control sample (without filler). Finally, the underlying mechanisms were discussed to explain the findings.
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Affiliation(s)
- Edgar-Homero Ramírez-Soria
- Advanced Functional Materials & Nanotechnology Group, Centro de Investigación en Materiales Avanzados S. C. (CIMAV-Unidad Monterrey), Av. Alianza Norte 202, Autopista Monterrey-Aeropuerto Km 10, PIIT, C.P. 66628 Apodaca-Nuevo León, México
| | - José Bonilla-Cruz
- Advanced Functional Materials & Nanotechnology Group, Centro de Investigación en Materiales Avanzados S. C. (CIMAV-Unidad Monterrey), Av. Alianza Norte 202, Autopista Monterrey-Aeropuerto Km 10, PIIT, C.P. 66628 Apodaca-Nuevo León, México
| | - Monica Gabriela Flores-Amaro
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León (UANL), AP 1864, 64570 Monterrey-Nuevo León, México
| | - Vincent Joseph García
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
- University of Tennessee, Knoxville, Tennessee 37996, United States
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Tania E Lara-Ceniceros
- Advanced Functional Materials & Nanotechnology Group, Centro de Investigación en Materiales Avanzados S. C. (CIMAV-Unidad Monterrey), Av. Alianza Norte 202, Autopista Monterrey-Aeropuerto Km 10, PIIT, C.P. 66628 Apodaca-Nuevo León, México
| | - Francisco E Longoria-Rodríguez
- Advanced Functional Materials & Nanotechnology Group, Centro de Investigación en Materiales Avanzados S. C. (CIMAV-Unidad Monterrey), Av. Alianza Norte 202, Autopista Monterrey-Aeropuerto Km 10, PIIT, C.P. 66628 Apodaca-Nuevo León, México
| | - Perla Elizondo
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León (UANL), AP 1864, 64570 Monterrey-Nuevo León, México
| | - Rigoberto C Advincula
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
- University of Tennessee, Knoxville, Tennessee 37996, United States
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
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Vavasori A, Bravo S, Pasinato F, Kudaibergenov N, Pietrobon L, Ronchin L. Supported palladium metal as heterogeneous catalyst precursor for the methoxycarbonylation of cyclohexene. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2019.110742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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