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Peidayesh H, Ondriš L, Saparová S, Kovaľaková M, Fričová O, Chodák I. Biodegradable Nanocomposites Based on Blends of Poly(Butylene Adipate-Co-Terephthalate) (PBAT) and Thermoplastic Starch Filled with Montmorillonite (MMT): Physico-Mechanical Properties. MATERIALS (BASEL, SWITZERLAND) 2024; 17:540. [PMID: 38591383 PMCID: PMC10856518 DOI: 10.3390/ma17030540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 01/01/2024] [Accepted: 01/08/2024] [Indexed: 04/10/2024]
Abstract
Poly(butylene adipate-co-terephthalate) (PBAT) is widely used for production of biodegradable films due to its high elongation, excellent flexibility, and good processability properties. An effective way to develop more accessible PBAT-based bioplastics for wide application in packaging is blending of PBAT with thermoplastic starch (TPS) since PBAT is costly with prices approximately double or even triple the prices of traditional plastics like polyethylene. This study is focused on investigating the influence of TPS/PBAT blend ratio and montmorillonite (MMT) content on the physical and mechanical properties and molecular mobility of TPS-MMT/PBAT nanocomposites. Obtained TPS-MMT/PBAT nanocomposites through the melt blending process were characterized using tensile testing, dynamic mechanical thermal analysis (DMTA), and X-ray diffraction (XRD), as well as solid-state 1H and 13C NMR spectroscopy. Mechanical properties demonstrated that the addition of TPS to PBAT leads to a substantial decrease in the tensile strength as well as in the elongation at break, while Young's modulus is rising substantially, while the effect of the MMT addition is almost negligible on the tensile stress of the blends. DMTA results confirmed the formation of TPS domains in the PBAT matrix. With increasing TPS content, mobility of starch-rich regions of TPS domains slightly increases. However, molecular mobility in glycerol-rich regions of TPS domains in the blends was slightly restricted. Moreover, the data obtained from 13C CP/MAS NMR spectra indicated that the presence of TPS in the sample decreases the mobility of the PBAT chains, mainly those located at the TPS/PBAT interfaces.
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Affiliation(s)
- Hamed Peidayesh
- Polymer Institute of the Slovak Academy of Sciences, Dúbravská Cesta 9, 845 41 Bratislava, Slovakia;
| | - Leoš Ondriš
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia (S.S.); (M.K.); (O.F.)
| | - Simona Saparová
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia (S.S.); (M.K.); (O.F.)
| | - Mária Kovaľaková
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia (S.S.); (M.K.); (O.F.)
| | - Oľga Fričová
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia (S.S.); (M.K.); (O.F.)
| | - Ivan Chodák
- Polymer Institute of the Slovak Academy of Sciences, Dúbravská Cesta 9, 845 41 Bratislava, Slovakia;
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Saparová S, Ondriš L, Kovaľaková M, Fričová O, Peidayesh H, Baran A, Hutníková M, Chodák I. Effects of glycerol content on structure and molecular motion in thermoplastic starch-based nanocomposites during long storage. Int J Biol Macromol 2023; 253:126911. [PMID: 37716657 DOI: 10.1016/j.ijbiomac.2023.126911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/04/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
Thermoplastic starch-based nanocomposites with varying glycerol content and montmorillonite as a nanofiller were studied using dynamic-mechanical analysis (DMA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) during one-year storage. DMA results showed that starch-rich and glycerol-rich domains were present in the samples and during storage for up to one year the content of the amorphous phase decreased and molecular mobility changed. 13C NMR and XRD measurements confirmed that ordered structures were formed during storage and its content was larger for samples with higher glycerol content and increased with the storage time. The data obtained from deconvolutions of 1H broad line NMR spectra indicate increased overall molecular mobility in the samples up to four months of storage, while after nine months the trends were opposite. Lower free water content compared to the total water content in the samples determined according to deconvoluted 1H MAS (magic-angle spinning) NMR spectra indicated that a part of water molecules was immobilized in the ordered structures.
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Affiliation(s)
- Simona Saparová
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia
| | - Leoš Ondriš
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia.
| | - Mária Kovaľaková
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia
| | - Oľga Fričová
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia
| | - Hamed Peidayesh
- Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava 45, Slovakia
| | - Anton Baran
- Department of Physics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Park Komenského 2, 042 00 Košice, Slovakia
| | - Mária Hutníková
- Department of Mathematics and Theoretical Informatics, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Boženy Němcovej 32, 042 00 Košice, Slovakia
| | - Ivan Chodák
- Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava 45, Slovakia
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Fričová O, Hutníková M. Changes in molecular mobility of sorbitol plasticized starch during aging. J Appl Polym Sci 2022. [DOI: 10.1002/app.52948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ol'ga Fričová
- Faculty of Electrical Engineering and Informatics Technical University of Košice Košice Slovakia
| | - Mária Hutníková
- Faculty of Electrical Engineering and Informatics Technical University of Košice Košice Slovakia
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Baran A, Fričová O, Vrábel P, Popovič Ľ, Peidayesh H, Chodák I, Hutníková M, Kovaľaková M. Effects of urea and glycerol mixture on morphology and molecular mobility in thermoplastic starch/montmorillonite-type nanofiller composites studied using XRD and NMR. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-022-03110-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wang F, Ramakrishna SK, Sun P, Fu R. Triple-pulse excitation: An efficient way for suppressing background signals and eliminating radio-frequency acoustic ringing in direct polarization NMR experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 332:107067. [PMID: 34634650 DOI: 10.1016/j.jmr.2021.107067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/06/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Direct polarization using a single pulse is the simplest excitation scheme in nuclear magnetic resonance (NMR) experiments, capable of quantifying various compositions in many materials applications. However, this single-pulse excitation generally gives rise to NMR spectra with a severely distorted baseline due to the background signals arising from probe components and/or due to the radio-frequency (RF) acoustic ringing, especially in low-γ nuclei and wide-line NMR. In this work, a triple-pulse excitation scheme is proposed to simultaneously suppress the background signals and eliminate the RF acoustic ringing. The acoustic ringing is cancelled through subtraction in any two consecutive scans by alternating the receiver phase while keeping the phase of the pulse right before acquisition the same. While the triple-pulse scheme generates an additional flip-angle dependent scaling to the traditional single-pulse excitation profile in such a way that the scaling is one when the flip-angle is ∼90° but becomes almost zero when the flip-angle is very small. Therefore, the background signals arising from the materials outside the sample coil experiencing a very small fraction of the RF flip-angles can be effectively suppressed. Various samples containing 1H and quadrupolar nuclei (17O, 25Mg, and 23Na) have been used to demonstrate the effectiveness of this newly proposed triple-pulse excitation in terms of suppressing the background signals and eliminating the acoustic ringing effects.
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Affiliation(s)
- Fenfen Wang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, State Key Laboratory of Medicinal Chemical Biology, Nankai University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300071, China
| | - Sanath K Ramakrishna
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA; National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials of the Ministry of Education and College of Chemistry, State Key Laboratory of Medicinal Chemical Biology, Nankai University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300071, China
| | - Riqiang Fu
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA.
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Matsuura BS, Huss S, Zheng Z, Yuan S, Wang T, Chen B, Badding JV, Trauner D, Elacqua E, van Duin ACT, Crespi VH, Schmidt-Rohr K. Perfect and Defective 13C-Furan-Derived Nanothreads from Modest-Pressure Synthesis Analyzed by 13C NMR. J Am Chem Soc 2021; 143:9529-9542. [PMID: 34130458 DOI: 10.1021/jacs.1c03671] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular structure of nanothreads produced by the slow compression of 13C4-furan was studied by advanced solid-state NMR. Spectral editing showed that >95% of carbon atoms were bonded to one hydrogen (C-H) and that there were 2-4% CH2, 0.6% C═O, and <0.3% CH3 groups. Alkenes accounted for 18% of the CH moieties, while trapped, unreacted furan made up 7%. Two-dimensional (2D) 13C-13C and 1H-13C NMR identified 12% of all carbon in asymmetric O-CH═CH-CH-CH- and 24% in symmetric O-CH-CH═CH-CH- rings. While the former represented defects or chain ends, some of the latter appeared to form repeating thread segments. Around 10% of carbon atoms were found in highly ordered, fully saturated nanothread segments. Unusually slow 13C spin-exchange with sites outside the perfect thread segments documented a length of at least 14 bonds; the small width of the perfect-thread signals also implied a fairly long, regular structure. Carbons in the perfect threads underwent relatively slow spin-lattice relaxation, indicating slow spin exchange with other threads and smaller amplitude motions. Through partial inversion recovery, the signals of the perfect threads were observed and analyzed selectively. Previously considered syn-threads with four different C-H bond orientations were ruled out by centerband-only detection of exchange NMR, which was, on the contrary, consistent with anti-threads. The observed 13C chemical shifts were matched well by quantum-chemical calculations for anti-threads but not for more complex structures like syn/anti-threads. These observations represent the first direct determination of the atomic-level structure of fully saturated nanothreads.
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Affiliation(s)
- Bryan S Matsuura
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Steven Huss
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zhaoxi Zheng
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Shichen Yuan
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Tao Wang
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bo Chen
- Donostia International Physics Center, Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - John V Badding
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Dirk Trauner
- Department of Chemistry, New York University, New York, New York 10003, United States
- Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016, United States
- NYU Neuroscience Institute, New York University School of Medicine, New York, New York 10016, United States
| | - Elizabeth Elacqua
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Adri C T van Duin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Vincent H Crespi
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
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Duan P, Lamm MS, Yang F, Xu W, Skomski D, Su Y, Schmidt-Rohr K. Quantifying Molecular Mixing and Heterogeneity in Pharmaceutical Dispersions at Sub-100 nm Resolution by Spin Diffusion NMR. Mol Pharm 2020; 17:3567-3580. [DOI: 10.1021/acs.molpharmaceut.0c00592] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Pu Duan
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Matthew S. Lamm
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Fengyuan Yang
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Wei Xu
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Daniel Skomski
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Yongchao Su
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
- Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
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8
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Fričová O, Hutníková M, Kovaľaková M, Baran A. Influence of aging on molecular motion in PBAT-thermoplastic starch blends studied using solid-state NMR. INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION 2020. [DOI: 10.1080/1023666x.2020.1783495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Oľga Fričová
- Faculty of Electrical Engineering and Informatics, Department of Physics, Technical University of Košice, Košice, Slovakia
| | - Mária Hutníková
- Faculty of Electrical Engineering and Informatics, Department of Physics, Technical University of Košice, Košice, Slovakia
| | - Mária Kovaľaková
- Faculty of Electrical Engineering and Informatics, Department of Physics, Technical University of Košice, Košice, Slovakia
| | - Anton Baran
- Faculty of Electrical Engineering and Informatics, Department of Physics, Technical University of Košice, Košice, Slovakia
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Baran A, Vrábel P, Kovaľaková M, Hutníková M, Fričová O, Olčák D. Effects of sorbitol and formamide plasticizers on molecular motion in corn starch studied using NMR and DMTA. J Appl Polym Sci 2020. [DOI: 10.1002/app.48964] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- A. Baran
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
| | - P. Vrábel
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
| | - M. Kovaľaková
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
| | - M. Hutníková
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
| | - O. Fričová
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
| | - D. Olčák
- Department of Physics, Faculty of Electrical Engineering and InformaticsTechnical University of Košice Park Komenského 2 042 00 Košice Slovakia
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Fritzsching KJ, Duan P, Alberts EM, Tibabuzo Perdomo AM, Kenny P, Wilker JJ, Schmidt-Rohr K. Silk-Like Protein with Persistent Radicals Identified in Oyster Adhesive by Solid-State NMR. ACS APPLIED BIO MATERIALS 2019; 2:2840-2852. [DOI: 10.1021/acsabm.9b00243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Keith J. Fritzsching
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Pu Duan
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | | | | | - Paul Kenny
- Baruch Marine Field Laboratory, University of South Carolina, P.O. Box 1630, Georgetown, South Carolina 29442, United States
| | | | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
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Duan P, Moreton JC, Tavares SR, Semino R, Maurin G, Cohen SM, Schmidt-Rohr K. Polymer Infiltration into Metal–Organic Frameworks in Mixed-Matrix Membranes Detected in Situ by NMR. J Am Chem Soc 2019; 141:7589-7595. [DOI: 10.1021/jacs.9b02789] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pu Duan
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Jessica C. Moreton
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Sergio R. Tavares
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier, Place E. Bataillon, 34095 Montpellier Cedex 05, France
| | - Rocio Semino
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier, Place E. Bataillon, 34095 Montpellier Cedex 05, France
| | - Guillaume Maurin
- Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Université de Montpellier, Place E. Bataillon, 34095 Montpellier Cedex 05, France
| | - Seth M. Cohen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
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Duan P, Schmidt-Rohr K. Quick, selective NMR spectra of COH moieties in 13C-enriched solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 301:80-84. [PMID: 30852301 DOI: 10.1016/j.jmr.2019.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 02/21/2019] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
A convenient one-dimensional magic-angle spinning NMR method is presented that provides selective NMR spectra of COH moieties in uniformly 13C-enriched organic materials. This method, termed hydroxyl-proton selection (HOPS), eliminates the magnetization of protons directly bonded to carbons by recoupling the 1H-13C dipolar interaction for a short time (∼70 μs), which also serves as a chemical-shift filter to suppress 1H magnetization of CH3 groups. After cross polarization to 13C, the signals of COH and COOH carbons are observed selectively. This makes it possible to distinguish alcohols from ethers, in particular phenols from aromatic ethers such as the furans often formed by dehydration of glucose, and carboxylic acids from carboxylates and ethers. HOPS NMR reveals that orthodiphenols are often a major component of low-temperature carbon materials. For instance, it forces the reassignment of the 143 ppm 13C NMR signal of hydrothermal carbon to such catecholic diphenols, while a previous NMR-based structural model had attributed this peak to a central furan-furan linkage.
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Affiliation(s)
- Pu Duan
- Department of Chemistry, Brandeis University, Waltham, MA 02453, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, Waltham, MA 02453, United States.
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Protective Carbon Overlayers from 2,3-Naphthalenediol Pyrolysis on Mesoporous SiO₂ and Al₂O₃ Analyzed by Solid-State NMR. MATERIALS 2018; 11:ma11060980. [PMID: 29890759 PMCID: PMC6025365 DOI: 10.3390/ma11060980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 11/28/2022]
Abstract
Hydrothermally stable carbon overlayers can protect mesoporous oxides (SiO2 and Al2O3) from hydrolysis during aqueous-phase catalysis. Overlayers made at 800 °C by pyrolysis of 2,3-naphthalenediol deposited out of acetone solution were analyzed by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Power absorption due to sample conductivity was prevented by diluting the sample in nonconductive and background-free tricalcium phosphate. While pyrolysis on SiO2 produced a predominantly aromatic carbon film, at least 15% of nonaromatic carbon (sp3-hybridized C as well as C=O) was observed on γ-Al2O3. These species were not derived from residual solvent, according to spectra of the same material treated at 400 °C. The sp3-hybridized C exhibited weak couplings to hydrogen, short spin-lattice relaxation times, and unusually large shift anisotropies, which are characteristics of tetrahedral carbon with high concentrations of unpaired electrons. Moderate heat treatment at 400 °C on SiO2 and Al2O3 resulted in yellow-brown and nearly black samples, respectively, but the darker color on Al2O3 did not correspond to more extensive carbonization. Aromatic carbon bonded to hydrogen remained predominant and the peaks of naphthalenediol were still recognizable; however, some of the chemical shifts differed by up to 5 ppm, indicating significant differences in local structure. On SiO2, additional sharp peaks were detected and attributed to 1/3 of the 2,3-naphthalene molecules undergoing fast, nearly isotropic motions.
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Mao J, Cao X, Olk DC, Chu W, Schmidt-Rohr K. Advanced solid-state NMR spectroscopy of natural organic matter. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 100:17-51. [PMID: 28552171 DOI: 10.1016/j.pnmrs.2016.11.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/15/2016] [Accepted: 11/28/2016] [Indexed: 06/07/2023]
Abstract
Solid-state NMR is essential for the characterization of natural organic matter (NOM) and is gaining importance in geosciences and environmental sciences. This review is intended to highlight advanced solid-state NMR techniques, especially a systematic approach to NOM characterization, and their applications to the study of NOM. We discuss some basics of how to acquire high-quality and quantitative solid-state 13C NMR spectra, and address some common technical mistakes that lead to unreliable spectra of NOM. The identification of specific functional groups in NOM, primarily based on 13C spectral-editing techniques, is described and the theoretical background of some recently-developed spectral-editing techniques is provided. Applications of solid-state NMR to investigating nitrogen (N) in NOM are described, focusing on limitations of the widely used 15N CP/MAS experiment and the potential of improved advanced NMR techniques for characterizing N forms in NOM. Then techniques used for identifying proximities, heterogeneities and domains are reviewed, and some examples provided. In addition, NMR techniques for studying segmental dynamics in NOM are reviewed. We also briefly discuss applications of solid-state NMR to NOM from various sources, including soil organic matter, aquatic organic matter, organic matter in atmospheric particulate matter, carbonaceous meteoritic organic matter, and fossil fuels. Finally, examples of NMR-based structural models and an outlook are provided.
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Affiliation(s)
- Jingdong Mao
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Blvd., Norfolk, VA 23529, United States.
| | - Xiaoyan Cao
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, United States.
| | - Dan C Olk
- National Laboratory for Agriculture and the Environment, 1015 N. University Blvd., Ames, IA 50011, United States.
| | - Wenying Chu
- Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Blvd., Norfolk, VA 23529, United States.
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453, United States.
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Fritzsching KJ, Mao K, Schmidt-Rohr K. Avoidance of Density Anomalies as a Structural Principle for Semicrystalline Polymers: The Importance of Chain Ends and Chain Tilt. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02000] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Keith J. Fritzsching
- Department of Chemistry, Brandeis University, 415 South St., Waltham, Massachusetts 02453, United States
| | - Kanmi Mao
- ExxonMobil Research and Engineering, 1545 Route 22 East, Annandale, New Jersey 08801, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Brandeis University, 415 South St., Waltham, Massachusetts 02453, United States
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Peng B, Shen M, Amoureux JP, Hu B. Elimination of the baseline distortions in WURST-CPMG static experiments. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2016; 78:1-4. [PMID: 27317974 DOI: 10.1016/j.ssnmr.2016.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/21/2016] [Accepted: 05/19/2016] [Indexed: 06/06/2023]
Abstract
The WURST-CPMG pulse sequence enables: (i) observing very broad spectra due to WURST excitation, and (ii) increasing the S/N ratio due to CPMG acquisition. However, strong baseline distortions may be observed, which make the extraction of the tensor information difficult. We propose a slight modification of the sequence, WURST-CPMGM, in which we skip the first M echoes and we only acquire the following ones. This simple treatment mostly eliminates the strong background signal and the ring down effects, leading to a flat baseline.
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Affiliation(s)
- Bo Peng
- School of Physics and Materials Science & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Ming Shen
- School of Physics and Materials Science & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China
| | - Jean-Paul Amoureux
- School of Physics and Materials Science & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China; UCCS, Lille North of France University, Villeneuve d'Ascq 59652, France
| | - Bingwen Hu
- School of Physics and Materials Science & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China.
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17
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Koval'aková M, Olčák D, Hronský V, Vrábel P, Fričová O, Chodák I, Alexy P, Sučik G. Morphology and molecular mobility of plasticized polylactic acid studied using solid-state13C- and1H-NMR spectroscopy. J Appl Polym Sci 2016. [DOI: 10.1002/app.43517] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mária Koval'aková
- Department of Physics; Faculty of Electrical Engineering and Informatics, Technical University of Košice; Park Komenského 2 042 00 Košice Slovakia
| | - Dušan Olčák
- Department of Physics; Faculty of Electrical Engineering and Informatics, Technical University of Košice; Park Komenského 2 042 00 Košice Slovakia
| | - Viktor Hronský
- Department of Physics; Faculty of Electrical Engineering and Informatics, Technical University of Košice; Park Komenského 2 042 00 Košice Slovakia
| | - Peter Vrábel
- Department of Physics; Faculty of Electrical Engineering and Informatics, Technical University of Košice; Park Komenského 2 042 00 Košice Slovakia
| | - Oľga Fričová
- Department of Physics; Faculty of Electrical Engineering and Informatics, Technical University of Košice; Park Komenského 2 042 00 Košice Slovakia
| | - Ivan Chodák
- Polymer Institute; Slovak Academy of Sciences; Dúbravská cesta 9 845 41 Bratislava Slovakia
| | - Pavel Alexy
- Institute of Natural and Synthetic Polymers; Slovak University of Technology; Radlinského 9 812 37 Bratislava Slovakia
| | - Gabriel Sučik
- Department of Ceramics; Faculty of Metallurgy, Technical University of Košice; Park Komenského 19 042 00 Košice Slovakia
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18
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Expanded graphite as superior anode for sodium-ion batteries. Nat Commun 2014; 5:4033. [DOI: 10.1038/ncomms5033] [Citation(s) in RCA: 1277] [Impact Index Per Article: 127.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 05/04/2014] [Indexed: 11/08/2022] Open
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19
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Jaeger C, Hemmann F. EASY: a simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy--part I: basic principle and applications. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2014; 57-58:22-8. [PMID: 24300107 DOI: 10.1016/j.ssnmr.2013.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 10/21/2013] [Accepted: 11/01/2013] [Indexed: 05/24/2023]
Abstract
Elimination of Artifacts in NMR SpectroscopY (EASY) is a simple but very effective tool to remove simultaneously any real NMR probe background signal, any spectral distortions due to deadtime ringdown effects and -specifically- severe acoustic ringing artifacts in NMR spectra of low-gamma nuclei. EASY enables and maintains quantitative NMR (qNMR) as only a single pulse (preferably 90°) is used for data acquisition. After the acquisition of the first scan (it contains the wanted NMR signal and the background/deadtime/ringing artifacts) the same experiment is repeated immediately afterwards before the T1 waiting delay. This second scan contains only the background/deadtime/ringing parts. Hence, the simple difference of both yields clean NMR line shapes free of artefacts. In this Part I various examples for complete (1)H, (11)B, (13)C, (19)F probe background removal due to construction parts of the NMR probes are presented. Furthermore, (25)Mg EASY of Mg(OH)2 is presented and this example shows how extremely strong acoustic ringing can be suppressed (more than a factor of 200) such that phase and baseline correction for spectra acquired with a single pulse is no longer a problem. EASY is also a step towards deadtime-free data acquisition as these effects are also canceled completely. EASY can be combined with any other NMR experiment, including 2D NMR, if baseline distortions are a big problem.
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Affiliation(s)
- Christian Jaeger
- BAM Federal Institute for Materials Research and Testing, Division 1, Richard Willstaetter Str. 11, D-12489 Berlin, Germany.
| | - Felix Hemmann
- BAM Federal Institute for Materials Research and Testing, Division 1, Richard Willstaetter Str. 11, D-12489 Berlin, Germany; Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
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20
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Karki I, Mihaliuk E, Gullion T. 1H-Observe1H2H Dipolar Recoupling by REDOR and Rotary Resonance Recoupling. Isr J Chem 2013. [DOI: 10.1002/ijch.201300098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Pajchel L, Kolodziejski W. Solid-state MAS NMR, TEM, and TGA studies of structural hydroxyl groups and water in nanocrystalline apatites prepared by dry milling. JOURNAL OF NANOPARTICLE RESEARCH : AN INTERDISCIPLINARY FORUM FOR NANOSCALE SCIENCE AND TECHNOLOGY 2013; 15:1868. [PMID: 23990754 PMCID: PMC3751289 DOI: 10.1007/s11051-013-1868-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Accepted: 07/15/2013] [Indexed: 05/31/2023]
Abstract
A series of nanocrystalline calcium hydroxyapatites was prepared by dry milling and characterized using proton and 31P MAS NMR, TEM, and TGA methods. The samples contained stubby rod-shaped crystals, which length and width varied in the 130-30 and 95-20 nm ranges, respectively. It was confirmed that concentration of structural hydroxyl groups in nanocrystalline apatites decreases with the decreasing crystal size. In the series of the studied apatites, the decrease was from 86 to ca. 50 % in reference to stoichiometric apatite. Water was found in the surface hydrated layer and in the c-axis channels, in which compartments existed as adsorbed and structural, respectively. Molecules of the adsorbed water were capable of moving from the crystal surface into the lattice c-axis channels of apatite. This process introduced considerable structural disorder within and around those channels and reduced the content of the structural hydroxyl groups, particularly in the region underneath the apatite crystal surface.
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Affiliation(s)
- Lukasz Pajchel
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, ul. Banacha 1, 02-097 Warsaw, Poland
| | - Waclaw Kolodziejski
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, ul. Banacha 1, 02-097 Warsaw, Poland
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22
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Borsacchi S, Sudhakaran U, Geppi M, Ricci L, Liuzzo V, Ruggeri G. Synthesis, characterization, and solid-state NMR investigation of organically modified bentonites and their composites with LDPE. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9164-9172. [PMID: 23786424 DOI: 10.1021/la401686p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Polymer/clay nanocomposites show remarkably improved properties (mechanical properties, as well as decreased gas permeability and flammability, etc.) with respect to their microscale counterparts and pristine polymers. Due to the substantially apolar character of most of the organic polymers, natural occurring hydrophilic clays are modified into organophilic clays with consequent increase of the polymer/clay compatibility. Different strategies have been developed for the preparation of nanocomposites with improved properties, especially aimed at achieving the best dispersion of clay platelets in the polymer matrix. In this paper we present the preparation and characterization of polymer/clay nanocomposites composed of low-density polyethylene (LDPE) and natural clay, montmorillonite-containing bentonite. Two different forms of the clay have been considered: the first, a commercial organophilic bentonite (Nanofil 15), obtained by exchanging the natural cations with dimethyldioctadecylammonium (2C18) cations, and the second, obtained by performing a grafting reaction of an alkoxysilane containing a polymerizable group, 3-(trimethoxysilyl)propyl methacrylate (TSPM), onto Nanofil 15. Both the clays and LDPE/clay nanocomposites were characterized by thermal, FT-IR, and X-ray diffraction techniques. The samples were also investigated by means of (29)Si, (13)C, and (1)H solid-state NMR, obtaining information on the structural properties of the modified clays. Moreover, by exploiting the effect of bentonite paramagnetic (Fe(3+)) ions on proton spin-lattice relaxation times (T1's), useful information about the extent of the polymer-clay dispersion and their interfacial interactions could be obtained.
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Affiliation(s)
- Silvia Borsacchi
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy.
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23
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Odedra S, Wimperis S. Imaging of the B1 distribution and background signal in a MAS NMR probehead using inhomogeneous B0 and B1 fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:95-99. [PMID: 23644349 DOI: 10.1016/j.jmr.2013.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 03/27/2013] [Accepted: 04/01/2013] [Indexed: 06/02/2023]
Abstract
Several widely used methods for suppressing the "background" signal in (1)H magic angle spinning (MAS) NMR spectroscopy are based on the assumption of a significant difference between the B1 radiofrequency field experienced by the sample (within the MAS rotor) and that felt by static components of the probehead (where the background signal is believed to originate). In this work, a two-dimensional correlation experiment employing inhomogeneous B0 and B1 fields is used to image the B1 distribution in a MAS NMR probehead. The experiment, which can be performed on any spectrometer, allows the distribution of the B1 field to be measured and also correlated with the spatial location of the NMR signal within the probehead. The method can also readily be combined with various "depth pulse" techniques for background suppression, allowing their performances to be more rigorously evaluated.
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Affiliation(s)
- Smita Odedra
- School of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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24
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Mollica G, Ziarelli F, Tintaru A, Thureau P, Viel S. Suppressing background signals in solid state NMR via the Electronic Mixing-Mediated Annihilation (EMMA) method. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 218:1-4. [PMID: 22578547 DOI: 10.1016/j.jmr.2012.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 03/02/2012] [Accepted: 03/17/2012] [Indexed: 05/31/2023]
Abstract
A simple procedure to effectively suppress background signals arising from various probe head components (e.g. stator, rotors, inserts) in solid state NMR is presented. Similarly to the ERETIC™ method, which uses an electronic signal as an internal standard for quantification, the proposed scheme is based on an electronically generated time-dependent signal that is injected into the receiver coil of the NMR probe head during signal acquisition. More specifically, the line shape, width and frequency of this electronic signal are determined by deconvoluting the background signal in the frequency domain. This deconvoluted signal is then converted into a time-dependent function through inverse Fourier Transform, which is used to generate the shaped pulse that is fed into the receiver coil during the acquisition of the Free Induction Decay. The power of the shaped pulse is adjusted to match the intensity of the background signal, and its phase is shifted by 180° with respect to the receiver reference phase. This so-called Electronic Mixing-Mediated Annihilation (EMMA) methodology is demonstrated here with a (13)C Single Pulse Magic Angle Spinning spectrum of an isotopically enriched (13)C histidine solid sample recorded under quantitative conditions.
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Affiliation(s)
- Giulia Mollica
- Aix-Marseille Univ. & CNRS, Institut de Chimie Radicalaire UMR 7273, Equipe Spectrométries Appliquées à la Chimie Structurale, av. Escadrille Normandie Niémen, case 512, F-13013 Marseille, France
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25
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Rawal A, Kong X, Meng Y, Otaigbe JU, Schmidt-Rohr K. Reduced Crystallinity and Mobility of Nylon-6 Confined near the Organic–Inorganic Interface in a Phosphate Glass-Rich Nanocomposite Detected by 1H–13C NMR. Macromolecules 2011. [DOI: 10.1021/ma201756q] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aditya Rawal
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Xueqian Kong
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Yan Meng
- School of Polymers and High Performance Materials, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Joshua U. Otaigbe
- School of Polymers and High Performance Materials, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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26
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Feng J, Reimer JA. Suppression of probe background signals via B(1) field inhomogeneity. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 209:300-305. [PMID: 21349751 DOI: 10.1016/j.jmr.2011.01.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/24/2011] [Accepted: 01/27/2011] [Indexed: 05/30/2023]
Abstract
A new approach combining a long pulse with the DEPTH sequence (Cory and Ritchey, Journal of Magnetic Resonance, 1988) greatly improves the efficiency for suppressing probe background signals arising from spinning modules. By applying a long initial excitation pulse in the DEPTH sequence, instead of a π/2 pulse, the inhomogeneous B(1) fields outside the coil can dephase the background coherence in the nutation frame. The initial long pulse and the following two consecutive EXORCYCLE π pulses function complementarily and prove most effective in removing background signals from both strong and weak B₁ fields. Experimentally, the length of the long pulse can be optimized around odd multiples of the π/2 pulse, depending on the individual probe design, to preserve signals inside the coil while minimizing those from probe hardware. This method extends the applicability of the DEPTH sequence to probes with small differences in B₁ field strength between the inside and outside of the coil, and can readily combine with well-developed double resonance experiments for quantitative measurement. In general, spin systems with weak internal interactions are required to attain efficient and uniform excitation for powder samples, and the principles to determine the applicability are discussed qualitatively in terms of the relative strength of spin interactions, r.f. power and spinning rate.
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Affiliation(s)
- Jian Feng
- Ernest Orlando Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, CA 94720, USA.
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27
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Kaflak A, Kolodziejski W. Complementary information on water and hydroxyl groups in nanocrystalline carbonated hydroxyapatites from TGA, NMR and IR measurements. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.01.056] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Shaibat MA, Casabianca LB, Siberio-Pérez DY, Matzger AJ, Ishii Y. Distinguishing polymorphs of the semiconducting pigment copper phthalocyanine by solid-state NMR and Raman spectroscopy. J Phys Chem B 2010; 114:4400-6. [PMID: 20225842 DOI: 10.1021/jp9061412] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cu(II)(phthalocyanine) (CuPc) is broadly utilized as an archetypal molecular semiconductor and is the most widely used blue printing pigment. CuPc crystallizes in six different forms; the chemical and physical properties are substantially modulated by its molecular packing among these polymorphs. Despite the growing importance of this system, spectroscopic identification of different polymorphs for CuPc has posed difficulties. This study presents the first example of spectroscopic distinction of alpha- and beta-forms of CuPc, the most widely used polymorphs, by solid-state NMR (SSNMR) and Raman spectroscopy. (13)C high-resolution SSNMR spectra of alpha- and beta-CuPc using very-fast magic angle spinning (VFMAS) at 20 kHz show that hyperfine shifts sensitively reflect polymorphs of CuPc. The experimental results were confirmed by ab initio chemical shift calculations. (13)C and (1)H SSNMR relaxation times of alpha- and beta-CuPc under VFMAS also showed marked differences, presumably because of the difference in electronic spin correlation times in the two forms. Raman spectroscopy also provided another reliable method of differentiation between the two polymorphs.
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Affiliation(s)
- Medhat A Shaibat
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, USA
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29
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Sobczak M, Chreptowicz T, Kolmas J, Kolodziejski W. Kinetics of solid-state NMR cross-polarization from protons to carbon-13 in surgical sutures. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 35:230-234. [PMID: 19217760 DOI: 10.1016/j.ssnmr.2009.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Accepted: 01/06/2009] [Indexed: 05/27/2023]
Abstract
Commercial Dexon surgical sutures, made of polyglycolide (PGA), were examined using (13)C CP/MAS NMR. The study shows that detailed analysis of the cross-polarization (CP) process is useful in the peak assignments and in the assessment of molecular mobility in the polymer domains. Crystallinity of PGA in the sutures was estimated at ca. 55%.
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Affiliation(s)
- Marcin Sobczak
- Department of Inorganic and Analytical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warszawa, Poland
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30
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Fang X, Mao J, Levin EM, Schmidt-Rohr K. Nonaromatic Core−Shell Structure of Nanodiamond from Solid-State NMR Spectroscopy. J Am Chem Soc 2009; 131:1426-35. [DOI: 10.1021/ja8054063] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- XiaoWen Fang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - JingDong Mao
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - E. M. Levin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
| | - Klaus Schmidt-Rohr
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, Ames Laboratory DOE, Ames, Iowa 50011, and Department of Physics and Astronomy, Iowa State University, Iowa 50011
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31
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Chen Q, Schmidt-Rohr K. Backbone Dynamics of the Nafion Ionomer Studied by19F-13C Solid-State NMR. MACROMOL CHEM PHYS 2007. [DOI: 10.1002/macp.200700200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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32
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Levin EM, Bud'ko SL, Mao JD, Huang Y, Schmidt-Rohr K. Effect of magnetic particles on NMR spectra of Murchison meteorite organic matter and a polymer-based model system. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2007; 31:63-71. [PMID: 17324558 DOI: 10.1016/j.ssnmr.2007.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 11/29/2006] [Accepted: 01/18/2007] [Indexed: 05/14/2023]
Abstract
Organic matter from the Murchison meteorite shows pronounced spinning sidebands of the (1)H MAS NMR spectrum and exhibits a large bulk magnetization of 0.75emicro/g extrapolated to 94kOe at 300K. By comparison with data of diamagnetic polystyrene and laponite clay mixed with ferrimagnetic gamma-Fe(2)O(3) nano-particles, we show that the spinning sidebands arise from a combination of dipolar couplings of a given (1)H to magnetic particles, seen in a backscattered-electron image, and to other protons. Signal loss and significant broadening of protonated-carbon peaks in (13)C MAS NMR spectra of polystyrene with Fe(2)O(3) nano-particles is demonstrated, and implications for (13)C NMR spectroscopy of Murchison meteorite are discussed.
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Affiliation(s)
- E M Levin
- Ames Laboratory DOE, Iowa State University, Ames, IA 50011-3020, USA
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33
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Kolmas J, Kolodziejski W. Concentration of hydroxyl groups in dental apatites: a solid-state 1H MAS NMR study using inverse 31P →1H cross-polarization. Chem Commun (Camb) 2007:4390-2. [DOI: 10.1039/b708317c] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Enlow D, Rawal A, Kanapathipillai M, Schmidt-Rohr K, Mallapragada S, Lo CT, Thiyagarajan P, Akinc M. Synthesis and characterization of self-assembled block copolymer templated calcium phosphate nanocomposite gels. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b613760a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Mao JD, Schmidt-Rohr K. Absence of mobile carbohydrate domains in dry humic substances proven by NMR, and implications for organic-contaminant sorption models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:1751-6. [PMID: 16570593 DOI: 10.1021/es0511467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The mobility and domain structure of various standard humic substances have been investigated by 1H and 1H-13C solid-state nuclear magnetic resonance (NMR) experiments. In four dry humic acids, a fulvic acid, a natural organic matter sample, and a whole peat sample, segments that undergo fast, large-amplitude motions account for <9% of the sample. This disproves a previous suggestion, based on 1H NMR data, that flexible domains, presumably carbohydrates, make up >40% of various humic acids; these putative mobile domains were also linked to dual-mode sorption. In particular, neither the polar alkyl (carbohydrate) nor the aromatic components show any fast, large-amplitude mobility. A small fraction of mobile nonpolar alkyl segments identified by us before is the only component undergoing large-amplitude motions, apart from absorbed water that we observe in humic acids exposed to ambient air. 1H-13C wide-line separation NMR shows that, contrary to previous suggestions, the dipolar couplings in the aromatic regions are smaller than in the polar alkyl segments, most likely due to differences in local 1H densities. Series of 1H-13C heteronuclear correlation experiments with 1H spin diffusion reveal close proximity of aromatic and polar alkyl segments in several humic acids, precluding carbohydrate domains on a scale of > 1-nm diameter. In the standard peat humic acid, nonpolar aromatic segments also do not form sorption domains of significant size, while nonpolar aliphatic domains, which we had previously shown to correlate with sorption capacity, have been confirmed.
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Affiliation(s)
- J D Mao
- Department of Chemistry, Gilman Hall, Iowa State University, Iowa 50011, USA
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