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Influence of Sulfur-Curing Conditions on the Dynamics and Crosslinking of Rubber Networks: A Time-Domain NMR Study. Polymers (Basel) 2022; 14:polym14040767. [PMID: 35215681 PMCID: PMC8880187 DOI: 10.3390/polym14040767] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 11/25/2022] Open
Abstract
The characterization of the structural and dynamic properties of rubber networks is of fundamental importance in rubber science and technology to design materials with optimized mechanical properties. In this work, natural and isoprene rubber networks obtained by curing at three different temperatures (140, 150, and 170 °C) and three different sulfur contents (1, 2, and 3 phr) in the presence of a 3 phr accelerator were studied using a combination of low-field time-domain NMR (TD-NMR) techniques, including 1H multiple-quantum experiments for the measurement of residual dipolar couplings (Dres), the application of the Carr–Purcell–Meiboom–Gill pulse sequence for the measurement of the transverse magnetization decay and the extraction of 1H T2 relaxation times, and the use of field cycling NMR relaxometry for the determination of T1 relaxation times. The microscopic properties determined by TD-NMR experiments were discussed in comparison with the macroscopic properties obtained using equilibrium swelling, moving die rheometer, and calorimetric techniques. The obtained correlations between NMR observables, crosslink density values, maximum torque values, and glass transition temperatures provided insights into the effects of the vulcanization temperature and accelerator/sulfur ratio on the structure of the polymer networks, as well as on the effects of crosslinking on the segmental dynamics of elastomers. Dres and T2 were found to show linear correlations with the crosslink density determined by equilibrium swelling, while T1 depends on the local dynamics of polymer segments related to the glass transition, which is also affected by chemical modifications of the polymer chains occurring during vulcanization.
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2
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Nardelli F, Martini F, Carignani E, Rossi E, Borsacchi S, Cettolin M, Susanna A, Arimondi M, Giannini L, Geppi M, Calucci L. Glassy and Polymer Dynamics of Elastomers by 1H-Field-Cycling NMR Relaxometry: Effects of Fillers. J Phys Chem B 2021; 125:4546-4554. [PMID: 33885314 PMCID: PMC8279540 DOI: 10.1021/acs.jpcb.1c00885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/07/2021] [Indexed: 11/30/2022]
Abstract
1H spin-lattice relaxation rate (R1) dispersions were acquired by field-cycling (FC) NMR relaxometry between 0.01 and 35 MHz over a wide temperature range on polyisoprene rubber (IR), either unfilled or filled with different amounts of carbon black, silica, or a combination of both, and sulfur cured. By exploiting the frequency-temperature superposition principle and constructing master curves for the total FC NMR susceptibility, χ″(ω) = ωR1(ω), the correlation times for glassy dynamics, τs, were determined. Moreover, the contribution of polymer dynamics, χpol″(ω), to χ″(ω) was singled out by subtracting the contribution of glassy dynamics, χglass″(ω), well represented by the Cole-Davidson spectral density. Glassy dynamics resulted moderately modified by the presence of fillers, τs values determined for the filled rubbers being slightly different from those of the unfilled one. Polymer dynamics was affected by the presence of fillers in the Rouse regime. A change in the frequency dependence of χpol″(ω) at low frequencies was observed for all filled rubbers, more pronounced for those reinforced with silica, which suggests that the presence of the filler particles can affect chain conformations, resulting in a different Rouse mode distribution, and/or interchain interactions modulated by translational motions.
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Affiliation(s)
- Francesca Nardelli
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
| | - Francesca Martini
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
- Centro
per l’Integrazione della Strumentazione Scientifica dell’Università
di Pisa (CISUP), Lungarno
Pacinotti 43, 56126 Pisa, Italy
| | - Elisa Carignani
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
| | - Elena Rossi
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Silvia Borsacchi
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
- Centro
per l’Integrazione della Strumentazione Scientifica dell’Università
di Pisa (CISUP), Lungarno
Pacinotti 43, 56126 Pisa, Italy
| | | | | | | | - Luca Giannini
- Pirelli
Tyre SpA, Viale Sarca 222, 20126 Milano, Italy
| | - Marco Geppi
- Dipartimento
di Chimica e Chimica Industriale, Università
di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
- Centro
per l’Integrazione della Strumentazione Scientifica dell’Università
di Pisa (CISUP), Lungarno
Pacinotti 43, 56126 Pisa, Italy
| | - Lucia Calucci
- Istituto
di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle
Ricerche, via G. Moruzzi
1, 56124 Pisa, Italy
- Centro
per l’Integrazione della Strumentazione Scientifica dell’Università
di Pisa (CISUP), Lungarno
Pacinotti 43, 56126 Pisa, Italy
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Danielsen SPO, Beech HK, Wang S, El-Zaatari BM, Wang X, Sapir L, Ouchi T, Wang Z, Johnson PN, Hu Y, Lundberg DJ, Stoychev G, Craig SL, Johnson JA, Kalow JA, Olsen BD, Rubinstein M. Molecular Characterization of Polymer Networks. Chem Rev 2021; 121:5042-5092. [PMID: 33792299 DOI: 10.1021/acs.chemrev.0c01304] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polymer networks are complex systems consisting of molecular components. Whereas the properties of the individual components are typically well understood by most chemists, translating that chemical insight into polymer networks themselves is limited by the statistical and poorly defined nature of network structures. As a result, it is challenging, if not currently impossible, to extrapolate from the molecular behavior of components to the full range of performance and properties of the entire polymer network. Polymer networks therefore present an unrealized, important, and interdisciplinary opportunity to exert molecular-level, chemical control on material macroscopic properties. A barrier to sophisticated molecular approaches to polymer networks is that the techniques for characterizing the molecular structure of networks are often unfamiliar to many scientists. Here, we present a critical overview of the current characterization techniques available to understand the relation between the molecular properties and the resulting performance and behavior of polymer networks, in the absence of added fillers. We highlight the methods available to characterize the chemistry and molecular-level properties of individual polymer strands and junctions, the gelation process by which strands form networks, the structure of the resulting network, and the dynamics and mechanics of the final material. The purpose is not to serve as a detailed manual for conducting these measurements but rather to unify the underlying principles, point out remaining challenges, and provide a concise overview by which chemists can plan characterization strategies that suit their research objectives. Because polymer networks cannot often be sufficiently characterized with a single method, strategic combinations of multiple techniques are typically required for their molecular characterization.
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Affiliation(s)
- Scott P O Danielsen
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Haley K Beech
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Shu Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Bassil M El-Zaatari
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Xiaodi Wang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | | | | | - Zi Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Patricia N Johnson
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Yixin Hu
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - David J Lundberg
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Georgi Stoychev
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Stephen L Craig
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Jeremiah A Johnson
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Julia A Kalow
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Bradley D Olsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Michael Rubinstein
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina 27599, United States.,Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Departments of Biomedical Engineering and Physics, Duke University, Durham, North Carolina 27708, United States.,World Primer Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
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4
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Martini F, Carignani E, Nardelli F, Rossi E, Borsacchi S, Cettolin M, Susanna A, Geppi M, Calucci L. Glassy and Polymer Dynamics of Elastomers by 1H Field-Cycling NMR Relaxometry: Effects of Cross-Linking. Macromolecules 2020; 53:10028-10039. [PMID: 33250523 PMCID: PMC7690040 DOI: 10.1021/acs.macromol.0c01439] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/20/2020] [Indexed: 11/28/2022]
Abstract
![]()
1H spin lattice relaxation
rate (R1) dispersions were acquired by
field-cycling (FC) NMR relaxometry
between 0.01 and 35 MHz over a wide temperature range on polyisoprene
(IR), polybutadiene (BR), and poly(styrene-co-butadiene)
(SBR) rubbers, obtained by vulcanization under different conditions,
and on the corresponding uncured elastomers. By exploiting the frequency–temperature
superposition principle, χ″(ωτs) master curves were constructed by shifting the total FC NMR susceptibility,
χ″(ω) = ωR1(ω),
curves along the frequency axis by the correlation times for glassy
dynamics, τs. Longer τs values and,
correspondingly, higher glass transition temperatures were determined
for the sulfur-cured elastomers with respect to the uncured ones,
which increased by increasing the cross-link density, whereas no significant
changes were found for fragility. The contribution of polymer dynamics,
χpol″(ω), to χ″(ω)
was singled out by subtracting the contribution of glassy dynamics,
χglass″(ω), well represented using a
Cole–Davidson spectral density. For all elastomers, χpol″(ω) was found to represent a small fraction, on the order of
0.05–0.14, of the total χ″(ω), which did
not show a significant dependence on cross-link density. In the investigated
temperature and frequency ranges, polymer dynamics was found to encompass
regimes I (Rouse dynamics) and II (constrained Rouse dynamics) of
the tube reptation model for the uncured elastomers and only regime
I for the vulcanized ones. This is clear evidence that chemical cross-links
impose constraints on chain dynamics on a larger space and time scale
than free Rouse modes.
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Affiliation(s)
- Francesca Martini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.,Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Elisa Carignani
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.,Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Francesca Nardelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.,Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Elena Rossi
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy
| | - Silvia Borsacchi
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
| | | | | | - Marco Geppi
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.,Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Lucia Calucci
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale Delle Ricerche, Via G. Moruzzi 1, 56124 Pisa, Italy
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Steele RM, Korb JP, Ferrante G, Bubici S. New applications and perspectives of fast field cycling NMR relaxometry. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:502-9. [PMID: 25855084 DOI: 10.1002/mrc.4220] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 12/17/2014] [Accepted: 01/19/2015] [Indexed: 05/08/2023]
Abstract
The field cycling NMR relaxometry method (also known as fast field cycling (FFC) when instruments employing fast electrical switching of the magnetic field are used) allows determination of the spin-lattice relaxation time (T1 ) continuously over five decades of Larmor frequency. The method can be exploited to observe the T1 frequency dependence of protons, as well as any other NMR-sensitive nuclei, such as (2) H, (13) C, (31) P, and (19) F in a wide range of substances and materials. The information obtained is directly correlated with the physical/chemical properties of the compound and can be represented as a 'nuclear magnetic resonance dispersion' curve. We present some recent academic and industrial applications showing the relevance of exploiting FFC NMR relaxometry in complex materials to study the molecular dynamics or, simply, for fingerprinting or quality control purposes. The basic nuclear magnetic resonance dispersion features are outlined in representative examples of magnetic resonance imaging (MRI) contrast agents, porous media, proteins, and food stuffs. We will focus on the new directions and perspectives for the FFC technique. For instance, the introduction of the latest Wide Bore FFC NMR relaxometers allows probing, for the first time, of the dynamics of confined surface water contained in the macro-pores of carbonate rock cores. We also evidence the use of the latest field cycling technology with a new cryogen-free variable-field electromagnet, which enhances the range of available frequencies in the 2D T1 -T2 correlation spectrum for separating oil and water in crude oil. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Jean-Pierre Korb
- Physique de la Matière Condensée, Ecole Polytechnique-CNRS, 91128, Palaiseau, France
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Toki S, Takagi R, Ito M, Hsiao BS. Rupture, orientation and strain-induced crystallization of polymer chain and network in vulcanized polyisoprene during uniaxial deformation by in-situ Electron Spin Resonance (ESR) and synchrotron X-ray analysis. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.03.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kariyo S, Stapf S, Blümich B. Site Specific Proton and Deuteron NMR Relaxation Dispersion in Selectively Deuterated Polyisoprene Melts. MACROMOL CHEM PHYS 2005. [DOI: 10.1002/macp.200500020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Kariyo S, Stapf S. Restricted Molecular Dynamics of Polymer Chains by Means of NMR Field Cycling Relaxometry. MACROMOL CHEM PHYS 2005. [DOI: 10.1002/macp.200500044] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Kariyo S, Küppers M, Badiger MV, Prabhakar A, Jagadeesh B, Stapf S, Blümich B. Morphology and chain dynamics during collapse transition of PNIPAM gels studied by combined imaging, relaxometry and 129Xe spectroscopy techniques. Magn Reson Imaging 2005; 23:249-53. [PMID: 15833621 DOI: 10.1016/j.mri.2004.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Accepted: 11/12/2004] [Indexed: 11/18/2022]
Abstract
The temperature-induced shape transition of poly(N-isopropylacrylamide) gels of different cross-link densities was investigated by a combination of NMR techniques allowing the characterization of both the macroscopic collapse as well as the changes on a molecular scale related to the expulsion of water from the gel network. The proton-containing gel phase was visualized by swelling in heavy water, and the volume change was monitored by proton imaging for cross-link densities between 0.5% and 2.5%. Above the transition temperature of 35 degrees C, gel collapse led to a volume change of up to a factor of 17 for the gel of smallest cross-link density. Two spectral lines of 129Xe are found in the gel state and are assigned to the hydrophobic and hydrophilic parts of the network. In the collapsed state, the hydrophobic peak shows a strong shift while the hydrophilic peak disappears. A considerable shortening of both T1 and T2 of the gel protons upon collapse was found at a field of 4.7 T. At lower fields, the effect becomes more pronounced and qualitatively different dispersion behaviors between the swollen and the collapsed states are observed.
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Affiliation(s)
- Sobiroh Kariyo
- Department of Molecular Chemistry, ITMC, RWTH Aachen, 52074 Aachen, Germany
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