1
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Almeida LS, Garcia RHDS, Ticona J, Cuffini SL, deAzevedo ER, Colnago LA. NMR Longitudinal Rotating Frame Relaxation Time (T 1ρ) with a Weak Spin Locking Field as an Approach to Characterize Solid-State Active Pharmaceutical Ingredients: Proof of Concept. Anal Chem 2024; 96:8317-8324. [PMID: 38739544 DOI: 10.1021/acs.analchem.3c04935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Nuclear magnetic resonance (NMR) longitudinal rotating frame relaxation time (T1ρ), rarely used in low-field NMR, can be more effective than conventional T1 and T2 relaxation times to differentiate polymorphic forms of solid pharmaceuticals. This could be attributed to T1ρ sensibility to structural and molecular dynamics that can be enhanced by changing the strength of the oscillating magnetic field (B1) of spinlock pulses. Here, we compared the capacity of T1, T2, and T1ρ to differentiate inactive (A) and active (C) crystalline forms of the World Health Organization essential drug Mebendazole. The results showed that T1 and T2 values of both forms were statistically identical at 0.47 T. Conversely, T1ρ of both forms measured with weak spinlock B1 fields, ranging from 0.08 to 0.80 mT were statistically different in the same spectrometer. The T1ρ also has the limit of detection to detect the presence of at least 10% of inactive A form in the active C form. Therefore, T1ρ, measured with weak spinlock B1 fields can be an effective, streamlined, and complementary approach for characterizing not only solid active pharmaceutical ingredients but other solid-state materials as well.
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Affiliation(s)
- Luisa Souza Almeida
- São Carlos Institute of Chemistry, University of São Paulo, 13566-590 São Carlos, Brazil
| | | | - Julian Ticona
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, 12231-280 São José dos Campos, Brazil
| | - Silvia L Cuffini
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, 12231-280 São José dos Campos, Brazil
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2
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Time-domain NMR in polyolefin research. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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1H Time Domain NMR to probe microstructural and mobility changes in Polyamide 11 exposed to H2S scavengers. What type of information can be assessed? Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2022.110001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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4
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Garcia RHDS, Filgueiras JG, Colnago LA, de Azevedo ER. Real-Time Monitoring Polymerization Reactions Using Dipolar Echoes in 1H Time Domain NMR at a Low Magnetic Field. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020566. [PMID: 35056881 PMCID: PMC8778891 DOI: 10.3390/molecules27020566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/18/2021] [Accepted: 12/20/2021] [Indexed: 11/16/2022]
Abstract
1H time domain nuclear magnetic resonance (1H TD-NMR) at a low magnetic field becomes a powerful technique for the structure and dynamics characterization of soft organic materials. This relies mostly on the method sensitivity to the 1H-1H magnetic dipolar couplings, which depend on the molecular orientation with respect to the applied magnetic field. On the other hand, the good sensitivity of the 1H detection makes it possible to monitor real time processes that modify the dipolar coupling as a result of changes in the molecular mobility. In this regard, the so-called dipolar echoes technique can increase the sensitivity and accuracy of the real-time monitoring. In this article we evaluate the performance of commonly used 1H TD-NMR dipolar echo methods for probing polymerization reactions. As a proof of principle, we monitor the cure of a commercial epoxy resin, using techniques such as mixed-Magic Sandwich Echo (MSE), Rhim Kessemeier-Radiofrequency Optimized Solid Echo (RK-ROSE) and Dipolar Filtered Magic Sandwich Echo (DF-MSE). Applying a reaction kinetic model that supposes simultaneous autocatalytic and noncatalytic reaction pathways, we show the analysis to obtain the rate and activation energy for the epoxy curing reaction using the NMR data. The results obtained using the different NMR methods are in good agreement among them and also results reported in the literature for similar samples. This demonstrates that any of these dipolar echo pulse sequences can be efficiently used for monitoring and characterizing this type of reaction. Nonetheless, the DF-MSE method showed intrinsic advantages, such as easier data handling and processing, and seems to be the method of choice for monitoring this type of reaction. In general, the procedure is suitable for characterizing reactions involving the formation of solid products from liquid reagents, with some adaptations concerning the reaction model.
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Affiliation(s)
| | - Jefferson Gonçalves Filgueiras
- Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, Niterói 24020-007, RJ, Brazil;
- Instituto de Física, Universidade Federal do Rio de Janeiro, CP68528, Rio de Janeiro 21941-972, RJ, Brazil
| | - Luiz Alberto Colnago
- Embrapa Instrumentação, Rua XV de Novembro, 1452, São Carlos 13560-970, SP, Brazil;
| | - Eduardo Ribeiro de Azevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, São Carlos 13660-970, SP, Brazil
- Correspondence:
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5
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Bimodal 1H Double Quantum Build-Up Curves by Fourier and Laplace-like Transforms on Aged Cross-Linked Natural Rubber. Polymers (Basel) 2021; 13:polym13203523. [PMID: 34685281 PMCID: PMC8540486 DOI: 10.3390/polym13203523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/29/2021] [Accepted: 10/08/2021] [Indexed: 12/26/2022] Open
Abstract
The 1H DQ Fourier and Laplace-like spectra for a series of cross-linked natural rubber (NR) samples naturally aged during six years are presented and characterized. The DQ build-up curves of these samples present two peaks which cannot be described by classical functions. The DQ Fourier spectra can be obtained after a numeric procedure which introduces a correction time which depends less on the chosen approximation, spin-½ and isolated CH2 and CH3 functional groups. The DQ Fourier spectra are well described by the distributions of the residual dipolar coupling correlated with the distribution of the end-to-end vector of the polymer network, and with the second and fourth van Vleck moments. The deconvolution of DQ Fourier spectra with a sum of four Gaussian variates show that the center and the width of Gaussian functions increase linearly with the increase in the cross-link density. The Laplace-like spectra for the natural aged NR DQ build-up curves are presented. The centers of four Gaussian distributions obtained via both methods are consistent. The differences between the Fourier and Laplace-like spectra consist mainly of the spectral resolution in the favor of Laplace-like spectra. The last one was used to discuss the effect of natural aging for cross-linked NR.
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6
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Facchinatto WM, Dos Santos Garcia RH, Dos Santos DM, Fiamingo A, Menezes Flores DW, Campana-Filho SP, de Azevedo ER, Colnago LA. Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan. Carbohydr Polym 2021; 256:117576. [PMID: 33483071 DOI: 10.1016/j.carbpol.2020.117576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 12/11/2020] [Accepted: 12/27/2020] [Indexed: 11/19/2022]
Abstract
Chitosans with different average degrees of acetylation and weight molecular weight were analyzed by time-domain NMR relaxometry using the recently proposed pulse sequence named Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE) to acquire 1H NMR signal of solid-state materials. The NMR signal decay was composed of faster (tenths of μs) and longer components, where the mobile-part fraction exhibited an effective relaxation transverse time assigned to methyl hydrogens from N-acetyl-d-glucosamine (GlcNAc) units. The higher intrinsic mobility of methyl groups was confirmed via DIPSHIFT experiments by probing the 1H-13C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R2 > 0.93) between RK-ROSE signal profile and average degrees of acetylation and crystallinity index, thus indicating that time-domain NMR consists in a promising tool for structural and morphological characterization of chitosan.
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Affiliation(s)
- William Marcondes Facchinatto
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil.
| | - Rodrigo Henrique Dos Santos Garcia
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Danilo Martins Dos Santos
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
| | - Anderson Fiamingo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Douglas William Menezes Flores
- Superior College of Agriculture "Luiz de Queiroz", University of Sao Paulo, Av. Padua Dias 11, CEP 13418-900, Caixa Postal 9, Piracicaba, SP, Brazil
| | - Sérgio Paulo Campana-Filho
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Eduardo Ribeiro de Azevedo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Luiz Alberto Colnago
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
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7
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Weigler M, Combarro-Palacios I, Cerveny S, Vogel M. On the microscopic origins of relaxation processes in aqueous peptide solutions undergoing a glass transition. J Chem Phys 2020; 152:234503. [PMID: 32571076 DOI: 10.1063/5.0010312] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We combine broadband dielectric spectroscopy (BDS) with 1H and 2H nuclear magnetic resonance (NMR) to study molecular dynamics in mixtures of ε-polylysine with H2O or D2O. In BDS, four relaxation processes can be attributed to molecular dynamics. While the fastest process P1 obeys the Arrhenius law, the slowest process P4 shows prominent non-Arrhenius behavior typical of structural α relaxation. For the intermediate processes P2 and P3, the temperature dependence changes at the glass transition temperature Tg. The 1H and 2H NMR results yield insights into the molecular origins of these relaxation phenomena. In these NMR analyses, we exploit, in addition to the isotope selectivity of the method, the possibility to distinguish between various types of motion based on their respective line-shape effects and the capability to single out specific molecular moieties based on different spin-lattice relaxation behaviors. In this way, we reveal that process P1 results from the rotation of side and end groups of the peptide, while process P2 is caused by a reorientation of essentially all water molecules, which are quasi-isotropic and survive well below Tg. As for the peptide backbone dynamics, we find evidence that rotational motion of polar groups is involved in process P3 and that nonpolar regions show a dynamical process, which is located between P3 and P4. Thus, the NMR analyses do not yield evidence for coexisting fast peptide-decoupled and slow peptide-coupled water species, which contribute to BDS processes P2 and P3, respectively, but minor bimodality of water motion may remain undetected. Finally, it is demonstrated that the proton/deuteron exchange needs to be considered when interpreting experimental results for molecular dynamics in aqueous peptide solutions.
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Affiliation(s)
- M Weigler
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - I Combarro-Palacios
- Centro de Fisica Materiales (CSIC-UPV/EHU) - Material Physics Centre (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
| | - S Cerveny
- Centro de Fisica Materiales (CSIC-UPV/EHU) - Material Physics Centre (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
| | - M Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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8
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Qin Y, Qiao Y, Chassé W, Litvinov V, Men Y. Crystallinity of polyolefins with large side groups by low-field 1H NMR T 2 relaxometry: Isotactic Polybutene-1 with form II and I crystals. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 105:101637. [PMID: 31830666 DOI: 10.1016/j.ssnmr.2019.101637] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/08/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
Phase composition and molecular mobility were studied using 1H NMR T2 relaxometry in isotactic polybutene-1 (iPB-1) with two polymorphs - form I and II crystals. Several types of NMR relaxation methods and data analysis were evaluated for determining the most reliable way for studying physical phases in iPB-1. Three-phase model provided the most appropriate description of the phase composition in iPB-1, i.e., a crystal-amorphous interface separates the crystalline and the amorphous phases. Due to complex molecular mobility in iPB-1, the amount of rigid fraction should be considered as NMR crystallinity number. Two types of chain segments are present in the amorphous phase: (1) chain segments with anisotropic mobility due to chain anchoring to crystals and chain entanglements; and (2) highly mobile chain end segments. The polymorphic phase II to I transition causes significant immobilization of polymer chains in the crystalline and the amorphous phases. Molecular weight of iPB-1 largely influences phase composition and molecular mobility in crystalline and amorphous phases.
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Affiliation(s)
- Yanan Qin
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, 130022, Changchun, PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, PR China
| | - Yongna Qiao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, 130022, Changchun, PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, PR China
| | - Walter Chassé
- Westfälische Wilhelms-Universität, Institut für Physikalische Chemie, Corrensstraße 28/30, 48149, Münster, Germany
| | - Victor Litvinov
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, 130022, Changchun, PR China; V.Lit.Consult, Gozewijnstraat 4, 6191, WV Beek, the Netherlands.
| | - Yongfeng Men
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, 130022, Changchun, PR China; School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, PR China.
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9
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Garcia RHS, Filgueiras JG, deAzevedo ER, Colnago LA. Power-optimized, time-reversal pulse sequence for a robust recovery of signals from rigid segments using time domain NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 104:101619. [PMID: 31470338 DOI: 10.1016/j.ssnmr.2019.101619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/09/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
Time domain NMR (TD-NMR) has been widely used on the analysis of liquids or liquid components in heterogeneous materials such as food, biological tissues, synthetic and bio polymers, oil-bearing rocks, biomasses and cement-based materials. The use of TD-NMR for studying solid and soft mater has been growing in number and variety of applications, mostly for organic systems where the detection of 1H signals is highly advantageous. However, the strong 1H-1H dipolar interactions in solids make the 1H FID to decay in the same order of the dead time of most commercially available NMR probe heads. Thus, solid echoes are often used for recovering signals from solid components. In this article we reinvestigate the time-reversal solid-echo pulse sequence proposed by Rhim and Kessemeier, seeking for optimal pulse power and timing conditions that maximize its efficiency on recovering 1H signals from rigid segments. We show that under these optimized conditions, which we denote as Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE), the experiment can be more efficient than its most popular counterparts Solid-Echo (SE) and mixed-Magic Sandwich Echoes (mixed-MSE). Our results also suggest that, despite the finite pulse power, with current probe technology the RK-ROSE experiment is potentially able to provide an accurate estimation of rigid components, without relying on an external calibration using multiple standard samples, as usually done in SFC analysis of the FID signal. At last, we demonstrate that RK-ROSE can be adapted as a simple filter to supress signals from mobile segments in heterogeneous materials.
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Affiliation(s)
- Rodrigo H S Garcia
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil
| | - Jefferson G Filgueiras
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil
| | - Eduardo R deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13660-970, São Carlos, SP, Brazil.
| | - Luiz Alberto Colnago
- Embrapa Instrumentação, Rua XV de Novembro, 1452, 13560-970, Brazil, São Carlos, SP, Brazil.
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10
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Lozovoi A, Petrova L, Mattea C, Stapf S, Rössler EA, Fatkullin N. On the theory of the proton dipolar-correlation effect as a method for investigation of segmental displacement in polymer melts. J Chem Phys 2017; 147:074904. [DOI: 10.1063/1.4998184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Lozovoi
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - L. Petrova
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - C. Mattea
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - S. Stapf
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - E. A. Rössler
- Department Experimentalphysik II, University of Bayreuth, 95440 Bayreuth, Germany
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
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11
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Schäler K, Roos M, Micke P, Golitsyn Y, Seidlitz A, Thurn-Albrecht T, Schneider H, Hempel G, Saalwächter K. Basic principles of static proton low-resolution spin diffusion NMR in nanophase-separated materials with mobility contrast. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 72:50-63. [PMID: 26404771 DOI: 10.1016/j.ssnmr.2015.09.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
We review basic principles of low-resolution proton NMR spin diffusion experiments, relying on mobility differences in nm-sized phases of inhomogeneous organic materials such as block-co- or semicrystalline polymers. They are of use for estimates of domain sizes and insights into nanometric dynamic inhomogeneities. Experimental procedures and limitations of mobility-based signal decomposition/filtering prior to spin diffusion are addressed on the example of as yet unpublished data on semicrystalline poly(ϵ-caprolactone), PCL. Specifically, we discuss technical aspects of the quantitative, dead-time free detection of rigid-domain signals by aid of the magic-sandwich echo (MSE), and magic-and-polarization-echo (MAPE) and double-quantum (DQ) magnetization filters to select rigid and mobile components, respectively. Such filters are of general use in reliable fitting approaches for phase composition determinations. Spin diffusion studies at low field using benchtop instruments are challenged by rather short (1)H T1 relaxation times, which calls for simulation-based analyses. Applying these, in combination with domain sizes as determined by small-angle X-ray scattering, we have determined spin diffusion coefficients D for PCL (0.34, 0.19 and 0.032nm(2)/ms for crystalline, interphase and amorphous parts, respectively). We further address thermal-history effects related to secondary crystallization. Finally, the state of knowledge concerning the connection between D values determined locally at the atomic level, using (13)C detection and CP- or REDOR-based "(1)H hole burning" procedures, and those obtained by calibration experiments, is summarized. Specifically, the non-trivial dependence of D on the magic-angle spinning (MAS) frequency, with a minimum under static and a local maximum under moderate-MAS conditions, is highlighted.
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Affiliation(s)
- Kerstin Schäler
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Matthias Roos
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Peter Micke
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Yury Golitsyn
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Anne Seidlitz
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Thomas Thurn-Albrecht
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Horst Schneider
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Günter Hempel
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
| | - Kay Saalwächter
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany.
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12
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Pieruccini M, Alessandrini A, Sturniolo S, Corti M, Rigamonti A. Small and large scale segmental motion in polymers: estimating cooperativity length by ordinary relaxation experiments. POLYM INT 2015. [DOI: 10.1002/pi.4894] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Andrea Alessandrini
- CNR, Istituto Nanoscienze; v. Campi 213/A 41125 Modena Italy
- Dipartimento di Fisica Informatica e Matematica; Università di Modena e Reggio Emilia; v. Campi 213/A 41125 Modena Italy
| | - Simone Sturniolo
- Rutherford Appleton Laboratory, Department of Computer Science; Chilton OX11 0QX, Oxfordshire UK
- Dipartimento di Fisica; Università di Pavia; v. Bassi 6 27100 Pavia Italy
| | - Maurizio Corti
- Dipartimento di Fisica; Università di Pavia; v. Bassi 6 27100 Pavia Italy
| | - Attilio Rigamonti
- Dipartimento di Fisica; Università di Pavia; v. Bassi 6 27100 Pavia Italy
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13
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Malmierca MA, González-Jiménez A, Mora-Barrantes I, Posadas P, Rodríguez A, Ibarra L, Nogales A, Saalwächter K, Valentín JL. Characterization of Network Structure and Chain Dynamics of Elastomeric Ionomers by Means of 1H Low-Field NMR. Macromolecules 2014. [DOI: 10.1021/ma501208g] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- M. A. Malmierca
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - A. González-Jiménez
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - I. Mora-Barrantes
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - P. Posadas
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - A. Rodríguez
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - L. Ibarra
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
| | - A. Nogales
- Instituto de Estructura
de la Materia, IEM-CSIC, C/Serrano
121, 28006 Madrid, Spain
| | - K. Saalwächter
- Institut
für Physik − NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Strasse
7, D-06120 Halle, Germany
| | - J. L. Valentín
- Instituto de Ciencia
y Tecnología de Polímeros (CSIC), C/Juan de la Cierva, 3, 28006 Madrid, Spain
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14
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Bärenwald R, Goerlitz S, Godehardt R, Osichow A, Tong Q, Krumova M, Mecking S, Saalwächter K. Local Flips and Chain Motion in Polyethylene Crystallites: A Comparison of Melt-Crystallized Samples, Reactor Powders, and Nanocrystals. Macromolecules 2014. [DOI: 10.1021/ma500691k] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Ruth Bärenwald
- Institut
für Physik − NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str.
7, D-06120 Halle, Germany
| | - Sylvia Goerlitz
- Institut
für Physik − Allgemeine Werkstoffwissenschaften, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle, Germany
| | - Reinhold Godehardt
- Institut
für Physik − Allgemeine Werkstoffwissenschaften, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 3, D-06120 Halle, Germany
| | - Anna Osichow
- Chemische
Materialwissenschaft, Fachbereich Chemie, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany
| | - Qiong Tong
- Chemische
Materialwissenschaft, Fachbereich Chemie, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany
| | - Marina Krumova
- Chemische
Materialwissenschaft, Fachbereich Chemie, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany
| | - Stefan Mecking
- Chemische
Materialwissenschaft, Fachbereich Chemie, Universität Konstanz, Universitätsstr. 10, D-78457 Konstanz, Germany
| | - Kay Saalwächter
- Institut
für Physik − NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str.
7, D-06120 Halle, Germany
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15
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Fatkullin N, Mattea C, Stapf S. On the theory of double quantum NMR in polymer systems: the second cumulant approximation for many spin I = 1/2 systems. J Chem Phys 2013; 139:194905. [PMID: 24320353 DOI: 10.1063/1.4830410] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
General analytical expressions for Double Quantum Nuclear Magnetic Resonance (DQ NMR) kinetic curves of many-spin I = 1∕2 systems are derived with an accuracy of the second cumulant approximation. The expressions obtained exactly describe the initial part of the kinetic curves and provide a reasonable approximation up to times of about the effective spin-relaxation time. For the case when the system contains two isolated spins, this result exactly reproduces known expressions. In the case of polymer melts, the intermolecular magnetic dipole-dipole interactions significantly influence the time dependence of the DQ NMR kinetic curves.
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Affiliation(s)
- N Fatkullin
- Institute of Physics, Kazan Federal University, Kazan, 420008 Tatarstan, Russia
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16
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Schäler K, Achilles A, Bärenwald R, Hackel C, Saalwächter K. Dynamics in Crystallites of Poly(ε-caprolactone) As Investigated by Solid-State NMR. Macromolecules 2013. [DOI: 10.1021/ma401532v] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kerstin Schäler
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Straße
7, D-06120 Halle/Saale, Germany
| | - Anja Achilles
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Straße
7, D-06120 Halle/Saale, Germany
| | - Ruth Bärenwald
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Straße
7, D-06120 Halle/Saale, Germany
| | - Christiane Hackel
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Straße
7, D-06120 Halle/Saale, Germany
| | - Kay Saalwächter
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Straße
7, D-06120 Halle/Saale, Germany
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17
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Sturniolo S, Pieruccini M, Corti M, Rigamonti A. Probing α-relaxation with nuclear magnetic resonance echo decay and relaxation: a study on nitrile butadiene rubber. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 51-52:16-24. [PMID: 23379979 DOI: 10.1016/j.ssnmr.2012.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 12/26/2012] [Accepted: 12/29/2012] [Indexed: 06/01/2023]
Abstract
One dimensional (1)H NMR measurements have been performed to probe slow molecular motions in nitrile butadiene rubber (NBR) around its calorimetric glass transition temperature Tg. The purpose is to show how software aided data analysis can extract meaningful dynamical data from these measurements. Spin-lattice relaxation time, free induction decay (FID) and magic sandwich echo (MSE) measurements have been carried out at different values of the static field, as a function of temperature. It has been evidenced how the efficiency of the MSE signal in reconstructing the original FID exhibits a sudden minimum at a given temperature, with a slight dependence from the measuring frequency. Computer simulations performed with the software SPINEVOLUTION have shown that the minimum in the efficiency reconstruction of the MSE signal corresponds to the average motional frequency taking a value around the inter-proton coupling. The FID signals have been fitted with a truncated form of a newly derived exact correlation function for the transverse magnetization of a dipolar interacting spin pair, which allows one to avoid the restriction of the stationary and Gaussian approximations. A direct estimate of the conformational dynamics on approaching the Tg is obtained, and the results are in agreement with the analysis performed via the MSE reconstruction efficiency. The occurrence of a wide distribution of correlation frequencies for the chains motion, with a Vogel-Fulcher type temperature dependence, is addressed. A route for a fruitful study of the dynamics accompanying the glass transition by a variety of NMR measurements is thus proposed.
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Affiliation(s)
- Simone Sturniolo
- Dipartimento di Fisica A. Volta, Università di Pavia, Pavia, Italy.
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18
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Demco DE, Oros-Peusquens AM, Utiu L, Fechete R, Blümich B, Shah NJ. Molecular dynamics parameter maps by 1H Hahn echo and mixed-echo phase-encoding MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 227:1-8. [PMID: 23220231 DOI: 10.1016/j.jmr.2012.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 10/29/2012] [Accepted: 11/08/2012] [Indexed: 06/01/2023]
Abstract
Residual dipolar couplings and averaged correlation time maps in soft matter were obtained by mixed echo phase-encoding solid imaging (MIPSI). Use of the mixed echo in soft matter NMR imaging experiments has two crucial advantages: the signal intensity is recovered with a weak incoherence losses, and second, the intervals during which the phase-encoding evolution due to the magnetic field gradients takes place can be chosen to be much larger than with all other spin echo experiments and hence, a higher special resolution can be achieved. The parameter maps are compared to those obtained by the Hahn-echo phase-frequency encoding method. For both MRI methods the density operator formalism is applied in the average Hamiltonian approximation to describe the encoding of the spin echoes by the molecular motions. The results of preliminary experiments are presented.
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Affiliation(s)
- Dan E Demco
- Institute of Neuroscience and Medicine, Research Centre Jülich, Juelich, Germany.
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19
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Bärenwald R, Champouret Y, Saalwächter K, Schäler K. Determination of Chain Flip Rates in Poly(ethylene) Crystallites by Solid-State Low-Field 1H NMR for Two Different Sample Morphologies. J Phys Chem B 2012; 116:13089-97. [DOI: 10.1021/jp3061625] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Bärenwald
- Institut für
Physik −
NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle, Germany
| | - Y. Champouret
- Department of Materials, Loughborough University, Loughborough, LE11 3TU, U.K
- The Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The
Netherlands
| | - K. Saalwächter
- Institut für
Physik −
NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle, Germany
| | - K. Schäler
- Institut für
Physik −
NMR, Martin-Luther-Universität Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle, Germany
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20
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Sturniolo S, Saalwächter K. Breakdown in the efficiency factor of the mixed Magic Sandwich Echo: A novel NMR probe for slow motions. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.09.059] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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21
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Balaceanu A, Demco DE, Möller M, Pich A. Heterogeneous Morphology of Random Copolymer Microgels as Reflected in Temperature-Induced Volume Transition and 1H High-Resolution Transverse Relaxation NMR. MACROMOL CHEM PHYS 2011. [DOI: 10.1002/macp.201100340] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Balaceanu A, Demco DE, Möller M, Pich A. Microgel Heterogeneous Morphology Reflected in Temperature-Induced Volume Transition and 1H High-Resolution Transverse Relaxation NMR. The Case of Poly(N-vinylcaprolactam) Microgel. Macromolecules 2011. [DOI: 10.1021/ma200103y] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andreea Balaceanu
- Functional and Interactive Polymers, DWI RWTH Aachen University, Pauwelsstrasse 8, D-52074 Aachen, Germany
| | - Dan E. Demco
- Functional and Interactive Polymers, DWI RWTH Aachen University, Pauwelsstrasse 8, D-52074 Aachen, Germany
| | - Martin Möller
- Functional and Interactive Polymers, DWI RWTH Aachen University, Pauwelsstrasse 8, D-52074 Aachen, Germany
| | - Andrij Pich
- Functional and Interactive Polymers, DWI RWTH Aachen University, Pauwelsstrasse 8, D-52074 Aachen, Germany
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23
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Moldovan D, Fechete R, Demco DE, Culea E, Blümich B, Herrmann V, Heinz M. The heterogeneity of segmental dynamics of filled EPDM by (1)H transverse relaxation NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:156-162. [PMID: 21106419 DOI: 10.1016/j.jmr.2010.10.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 10/29/2010] [Accepted: 10/31/2010] [Indexed: 05/30/2023]
Abstract
Residual second moment of dipolar interactions M(2) and correlation time segmental dynamics distributions were measured by Hahn-echo decays in combination with inverse Laplace transform for a series of unfilled and filled EPDM samples as functions of carbon-black N683 filler content. The fillers-polymer chain interactions which dramatically restrict the mobility of bound rubber modify the dynamics of mobile chains. These changes depend on the filler content and can be evaluated from distributions of M(2). A dipolar filter was applied to eliminate the contribution of bound rubber. In the first approach the Hahn-echo decays were fitted with a theoretical relationship to obtain the average values of the (1)H residual second moment <M(2)> and correlation time <τ(c)>. For the mobile EPDM segments the power-law distribution of correlation function was compared to the exponential correlation function and found inadequate in the long-time regime. In the second approach a log-Gauss distribution for the correlation time was assumed. Furthermore, using an averaged value of the correlation time, the distributions of the residual second moment were determined using an inverse Laplace transform for the entire series of measured samples. The unfilled EPDM sample shows a bimodal distribution of residual second moments, which can be associated to the mobile polymer sub-chains (M(2) ≅ 6.1 rad (2) s(-2)) and the second one associated to the dangling chains M(2) ≅ 5.4 rad(2) s(-2)). By restraining the mobility of bound rubber, the carbon-black fillers induce diversity in the segmental dynamics like the apparition of a distinct mobile component and changes in the distribution of mobile and free-end polymer segments.
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Affiliation(s)
- D Moldovan
- Technical University of Cluj-Napoca, Daicoviciu 1, R-400020 Cluj-Napoca, Romania
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24
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Moldovan D, Fechete R, Demco DE, Culea E, Blümich B, Herrmann V, Heinz M. Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform 1
H NMR Relaxometry and Rheometry. MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.201000086] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Chelcea RI, Fechete R, Culea E, Demco DE, Blümich B. Distributions of transverse relaxation times for soft-solids measured in strongly inhomogeneous magnetic fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 196:178-190. [PMID: 19083248 DOI: 10.1016/j.jmr.2008.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 11/09/2008] [Accepted: 11/12/2008] [Indexed: 05/27/2023]
Abstract
The single-sided NMR-MOUSE sensor that operates in highly inhomogeneous magnetic fields is used to record a CPMG (1)H transverse relaxation decay by CPMG echo trains for a series of cross-linked natural rubber samples. Effective transverse relaxation rates 1/T(2,short) and 1/T(2,long) were determined by a bi-exponential fit. A linear dependence of transverse relaxation rates on cross-link density is observed for medium to large values of cross-link density. As an alternative to multi-exponential fits the possibility to analyze the dynamics of soft polymer network in terms of multi-exponential decays via the inverse Laplace transformation was studied. The transient regime and the effect of the T(1)/T(2) ratio in inhomogeneous static and radiofrequency magnetic fields on the CPMG decays were studied numerically using a dedicated C++ program to simulate the temporal and spatial dependence of the CPMG response. A correction factor T(2)/T(2,eff) is derived as a function of the T(1)/T(2) ratio from numerical simulations and compared with earlier results from two different well logging devices. High-resolution T(1)-T(2) correlations maps are obtained by two-dimensional Laplace inversion of CPMG detected saturation recovery curves. The T(1)-T(2) experimental correlations maps were corrected for the T(1)/T(2) effect using the derived T(2)/T(2,eff) correction factor.
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Affiliation(s)
- R I Chelcea
- Technical University of Cluj-Napoca, Daicoviciu 1, R-400020 Cluj-Napoca, Romania
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26
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Lewicki JP, Maxwell RS, Patel M, Herberg JL, Swain AC, Liggat JJ, Pethrick RA. Effect of meta-Carborane on Segmental Dynamics in a Bimodal Poly(dimethylsiloxane) Network. Macromolecules 2008. [DOI: 10.1021/ma801570e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James P. Lewicki
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - Robert S. Maxwell
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - Mogon Patel
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - Julie L. Herberg
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - Anthony C. Swain
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - John J. Liggat
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
| | - Richard A. Pethrick
- Lawrence Livermore National Laboratory, Livermore, California, Department of Pure and Applied Chemistry, Westchem, University of Strathclyde, Glasgow, Scotland, and Atomic Weapons Establishment, Aldermasten, United Kingdom
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27
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Goga NO, Demco DE, Kolz J, Ferencz R, Haber A, Casanova F, Blümich B. Surface UV aging of elastomers investigated with microscopic resolution by single-sided NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 192:1-7. [PMID: 18294890 DOI: 10.1016/j.jmr.2007.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2007] [Revised: 10/27/2007] [Accepted: 10/30/2007] [Indexed: 05/25/2023]
Abstract
Depth profiles taken from the surface of UV irradiated natural rubber sheets have been measured with microscopic resolution using a Profile NMR-MOUSE. An NMR observable related to the sum of the spin echoes in the Carr-Purcell-Meiboom-Gill pulse sequence was used to characterize the cross-link density changes produced by the action of UV radiation in each sheet. The aging process was investigated as function of irradiation time and penetration depth. An exponential attenuation law with a space dependent absorption coefficient describes the change in the NMR observable with penetration depth. An Avrami model is used to describe the dependence of the absorption coefficient on the aging time. The method can be applied to investigate the effect of various aging agents on the surfaces of elastomers.
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Affiliation(s)
- N O Goga
- Institute for Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 1, D-52072 Aachen, Germany
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28
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Mayer BP, Reimer JA, Maxwell RS. A Methodology for the Indirect Determination and Spatial Resolution of Shear Modulus of PDMS−Silica Elastomers. Macromolecules 2008. [DOI: 10.1021/ma702007m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian P. Mayer
- Department of Chemical Engineering, University of California, Berkeley, Berkeley, California 94720
| | - Jeffrey A. Reimer
- Department of Chemical Engineering, University of California, Berkeley, Berkeley, California 94720
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29
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Acosta RH, Vega DA, Villar MA, Monti GA, Vallés EM. Double Quantum NMR Applied to Polymer Networks with Low Concentration of Pendant Chains. Macromolecules 2006. [DOI: 10.1021/ma060011y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rodolfo H. Acosta
- LANAIS RMS-Fa.M.A.F, Universidad Nacional de Córdoba-CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba, Argentina; Department of Physics, Universidad Nacional del Sur-CONICET, Av. L. N. Alem 1253, 8000 Bahía Blanca, Argentina; and Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET), Camino La Carrindanga Km 7, CC717, 8000 Bahía Blanca, Argentina
| | - Daniel A. Vega
- LANAIS RMS-Fa.M.A.F, Universidad Nacional de Córdoba-CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba, Argentina; Department of Physics, Universidad Nacional del Sur-CONICET, Av. L. N. Alem 1253, 8000 Bahía Blanca, Argentina; and Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET), Camino La Carrindanga Km 7, CC717, 8000 Bahía Blanca, Argentina
| | - Marcelo A. Villar
- LANAIS RMS-Fa.M.A.F, Universidad Nacional de Córdoba-CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba, Argentina; Department of Physics, Universidad Nacional del Sur-CONICET, Av. L. N. Alem 1253, 8000 Bahía Blanca, Argentina; and Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET), Camino La Carrindanga Km 7, CC717, 8000 Bahía Blanca, Argentina
| | - Gustavo A. Monti
- LANAIS RMS-Fa.M.A.F, Universidad Nacional de Córdoba-CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba, Argentina; Department of Physics, Universidad Nacional del Sur-CONICET, Av. L. N. Alem 1253, 8000 Bahía Blanca, Argentina; and Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET), Camino La Carrindanga Km 7, CC717, 8000 Bahía Blanca, Argentina
| | - Enrique M. Vallés
- LANAIS RMS-Fa.M.A.F, Universidad Nacional de Córdoba-CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba, Argentina; Department of Physics, Universidad Nacional del Sur-CONICET, Av. L. N. Alem 1253, 8000 Bahía Blanca, Argentina; and Planta Piloto de Ingeniería Química, PLAPIQUI (UNS-CONICET), Camino La Carrindanga Km 7, CC717, 8000 Bahía Blanca, Argentina
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30
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Saalwächter K, Heuer A. Chain Dynamics in Elastomers As Investigated by Proton Multiple-Quantum NMR. Macromolecules 2006. [DOI: 10.1021/ma052567b] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kay Saalwächter
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - Andreas Heuer
- Institut für Physikalische Chemie, Universität Münster, Corrensstr. 30, D-48149 Münster, Germany
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31
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Saalwächter K, Herrero B, López-Manchado MA. Chain Order and Cross-Link Density of Elastomers As Investigated by Proton Multiple-Quantum NMR. Macromolecules 2005. [DOI: 10.1021/ma051238g] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kay Saalwächter
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - Berta Herrero
- Institute of Polymer Science and Technology (CSIC), C/ Juan de la Cierva 3, E-28006 Madrid, Spain
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32
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Sommer JU, Saalwächter K. Segmental order in end-linked polymer networks: a Monte Carlo study. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2005; 18:167-82. [PMID: 16240072 DOI: 10.1140/epje/i2005-10037-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 08/16/2005] [Indexed: 05/04/2023]
Abstract
Segmental order in end-linked monomodal and bimodal polymer networks is investigated by means of bond-fluctuation Monte Carlo simulations. The tensor order parameter, which is a central observable in NMR experiments, is not uniquely related to simple vectorial order. The relaxation of NMR-detected tensorial interactions towards their finite long-time limit is best described by a power law and occurs over much longer time scales than the relaxation of vectorial order. The well-known prediction for the segmental order of Gaussian chains as a simple function of the segment number between constraints is not straightforwardly obeyed, neither in dry nor in swollen networks. Excluded-volume interactions tend to significantly reduce the tensorial order, as is clearly observed in single-chain simulations. A distribution extends along the chain, where order is increased in a region of 30-40 bonds around the cross-links in networks. The dominating contribution to the order parameter distribution arises from the frozen-in distribution of end-to-end separations. We find strong deviations from the Gamma distribution, which has so far been implicitly used in most NMR works, as it is a straightforward consequence of a Gaussian distribution of end separations. Specifically, we find narrower distributions, as small values of the tensor order parameter are strongly suppressed, most probably as a result of trapped entanglements. The markedly subaffine behavior of the average order parameter and the changes in its distribution on swelling are assigned to orientation processes of strands which compensate for the non-affine local deformation. Our central observations and interpretations are well supported by our previous experimental and theoretical work.
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Affiliation(s)
- J-U Sommer
- Institut de Chimie des Surfaces et Interfaces (CNRS), 15 rue Jean Starcky, Mulhouse, France.
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33
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Saalwächter K. Artifacts in Transverse Proton NMR Relaxation Studies of Elastomers. Macromolecules 2005. [DOI: 10.1021/ma0478005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kay Saalwächter
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
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34
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Voda MA, Demco DE, Perlo J, Orza RA, Blümich B. Multispin moments edited by multiple-quantum NMR: application to elastomers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 172:98-109. [PMID: 15589413 DOI: 10.1016/j.jmr.2004.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Revised: 10/05/2004] [Indexed: 05/24/2023]
Abstract
The spin system response to the five-pulse sequence used for measurements of double-quantum and triple-quantum buildup curves is evaluated in the initial excitation/reconversion regime. The multispin dipolar network that is present also in many soft solids like elastomers was considered. It is proved rigorously that the relevant quantity for analysis of double-quantum build-up curves in the initial regime is the second van Vleck moment. The higher-order moments edited by double-quantum as well as higher-order coherences in the multiple-quantum build-up experiments are different from van Vleck moments. These results can be applied to compare (1)H residual moments edited by double-quantum and triple-quantum experiments with those measured by other NMR methods. The sensitivity of multiple-quantum coherences to the changes in the values of residual dipolar couplings for cross-linked natural rubber under uniaxial elongation is also discussed. Under such conditions (1)H second van Vleck moments were measured for different elongation ratios of a cross-linked natural rubber. Moreover, (1)H triple-quantum edited moments were also measured for the same sample under uniaxial compression. The dependence of the second van Vleck moment and the time of the maximum of the double-quantum buildup curve on the cross-link density of natural rubber measured at low magnetic field was also investigated.
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Affiliation(s)
- M A Voda
- Institut für Technische Chemie und Makromolekulare Chemie, Rheinisch-Westfälische Technische Hochschule, Worringerweg 1, D-52056 Aachen, Germany
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35
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Saalwächter K, Kleinschmidt F, Sommer JU. Swelling Heterogeneities in End-Linked Model Networks: A Combined Proton Multiple-Quantum NMR and Computer Simulation Study. Macromolecules 2004. [DOI: 10.1021/ma048803k] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kay Saalwächter
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - Felix Kleinschmidt
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany
| | - Jens-Uwe Sommer
- Institut de Chimie des Surfaces et Interfaces (CNRS), 15, rue Jean Starcky, F-68057 Mulhouse Cedex, France
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Fechete R, Demco DE, Blümich B. Enhanced sensitivity to residual dipolar couplings of elastomers by higher-order multiple-quantum NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 169:19-26. [PMID: 15183352 DOI: 10.1016/j.jmr.2004.03.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 03/29/2004] [Indexed: 05/24/2023]
Abstract
The homonuclear and heteronuclear residual dipolar couplings in elastomers reflect changes in the cross-link density, temperature, the uniaxial and biaxial extension or compression as well as the presence of penetrant molecules. It is shown theoretically that for an isolated methyl group the relative changes in the intensity of the homonuclear double-quantum buildup curves in the initial time regime due to variation of the residual dipolar coupling strength is less sensitive than the changes in the triple-quantum filtered NMR signal when considering the same excitation/reconversion time. For a quadrupolar nucleus with spin I=2 the sensitivity enhancement was simulated for four-quantum, triple-quantum, and double-quantum buildup curves. In this case the four-quantum build-up curve shows the highest sensitivity to changes of spin couplings. This enhanced sensitivity to the residual dipolar couplings was tested experimentally by measuring 1H double-quantum, triple-quantum, and four-quantum buildup curves of differently cross-linked natural rubber samples. In the initial excitation/reconversion time regime, where the residual dipolar couplings can be measured model free, the relative changes in the intensity of the four-quantum buildup curves are about five times higher than those of the double-quantum coherences. For the first time proton four-quantum coherences were recorded for cross-linked elastomers.
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Affiliation(s)
- R Fechete
- Institut für Technische Chemie und Makromolekulare Chemie, Rheinisch-Westfälische Technische Hochschule, Worringerweg 1, D-52056 Aachen, Germany
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Wang M, Bertmer M, Demco DE, Blümich B. Segmental and Local Chain Mobilities in Elastomers by13C−1H Residual Heteronuclear Dipolar Couplings. J Phys Chem B 2004. [DOI: 10.1021/jp048392+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Saalwächter K. 1H multiple-quantum nuclear magnetic resonance investigations of molecular order in polymer networks. II. Intensity decay and restricted slow dynamics. J Chem Phys 2004; 120:454-64. [PMID: 15267307 DOI: 10.1063/1.1630561] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an approach towards the analysis of the intensity decay in proton multiple-quantum experiments on polymeric networks in terms of slow fluctuations of the residual dipole-dipole coupling tensor. Solutions for individual spin pairs as well as the three-spin system of methyl groups are derived, and the influence of the cycle time of the multiple-quantum pulse sequence is evaluated. The multiple-quantum strategy discussed herein features the advantage that the magnitude of the fluctuating part of the residual dipole-dipole coupling constant and the correlation time of the slow process can be determined independently of the integral residual coupling constant as well as its distribution. The theory is applied to experiments on end-linked poly(dimethylsiloxane) model networks with mono- and bimodal chain length distributions, where it is found that, for all samples, correlation times of the slow processes average to about 1 ms, and that the magnitude of the fluctuating part of the dipole-dipole coupling is significantly smaller than the average dipole-dipole coupling constant. This observation is interpreted in terms of considerably restricted reorientations of topological constraints.
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Affiliation(s)
- Kay Saalwächter
- Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany.
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Fechete R, Demco DE, Blümich B. Parameter maps of 1H residual dipolar couplings in tendon under mechanical load. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 165:9-17. [PMID: 14568513 DOI: 10.1016/s1090-7807(03)00278-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Proton multipolar spin states associated with dipolar encoded longitudinal magnetization (DELM) and double-quantum (DQ) coherences of bound water are investigated for bovine and sheep Achilles tendon under mechanical load. DELM decay curves and DQ buildup and decay curves reveal changes of the 1H residual dipolar couplings for tendon at rest and under local compression forces. The multipolar spin states are used to design dipolar contrast filters for NMR 1H images of heterogeneous tendon. Heterogeneities in tendon samples were artificially generated by local compression parallel and perpendicular to the tendon plug axis. Quotient images obtained from DQ-filtered images by matched and mismatched excitation/reconversion periods are encoded only by the residual dipolar couplings. Semi-quantitative parameter maps of the residual dipolar couplings of bound water were obtained from these quotient images using a reference elastomer sample. This method can be used to quantify NMR imaging of injured ordered tissues.
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Affiliation(s)
- R Fechete
- Institut für Technische Chemie und Makromolekulare Chemie, Rheinisch-Westfälische Technische Hochschule, Worringerweg 1, D-52056, Aachen, Germany
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Fechete R, Demco DE, Blümich B. Self-Diffusion Anisotropy of Small Penetrants in Compressed Elastomers. Macromolecules 2003. [DOI: 10.1021/ma030275+] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Saalwächter K, Ziegler P, Spyckerelle O, Haidar B, Vidal A, Sommer JU. 1H multiple-quantum nuclear magnetic resonance investigations of molecular order distributions in poly(dimethylsiloxane) networks: Evidence for a linear mixing law in bimodal systems. J Chem Phys 2003. [DOI: 10.1063/1.1589000] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Demco D, Fechete R, Blümich B. Residual dipolar couplings of soft solids by accordion magic sandwich. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)00874-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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