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Sulatha MS, Natarajan U. Effect of chemical substituents on the structure of glassy diphenyl polycarbonates. J Phys Chem B 2011; 115:1579-89. [PMID: 21275412 DOI: 10.1021/jp105954z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polycarbonates offer a wide variety of physical property behavior that is difficult to predict due to complexities at the molecular scale. Here, the physical structure of amorphous glassy polycarbonates having aliphatic and cycloaliphatic chemical groups is explored through atomistic simulations. The influence of chemical structure on solubility parameter, torsion distributions, radial distribution function, scattering structure factor, orientation distributions of phenylene rings and carbonate groups, and free volume distributions, leading to interchain packing effects, are shown. The effect of the cyclohexyl ring at the isopropylidene carbon as compared to the effect of the methyl groups positioned on the phenylene rings results in a larger reduction in the solubility parameter (δ). The interchain distance estimated for polycarbonates in this work is in the range of 5-5.8 Å. The o-methyl groups on the phenylene rings, as compared to a cyclohexyl ring, lead to higher interchain distances. The highest interchain distance is observed with a trimethylcyclohexylidene group at the isopropylidene carbon. Atomistic simulations reveal two different types of packing arrangement of nearest-neighbor chains in the glassy state, one type of which agrees with the NMR experimental data. The fundamental insights provided here can be utilized for design of chemical structures for tailored macroscopic properties.
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Affiliation(s)
- M S Sulatha
- Macromolecular Modeling and Simulation Laboratory, Polymer Chemistry Division, National Chemical Laboratory (NCL), Pune 411 008, India
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Stueber D, Yu TY, Hess B, Kremer K, O'Connor RD, Schaefer J. Chain packing in polycarbonate glasses. J Chem Phys 2010; 132:104901. [PMID: 20232984 DOI: 10.1063/1.3330412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Chain packing in homogeneous blends of carbonate (13)C-labeled bisphenol A polycarbonate with either (i) CF(3)-labeled bisphenol A polycarbonate or (ii) ring-F-labeled bisphenol A polycarbonate has been characterized using (13)C{(19)F} rotational-echo double-resonance (REDOR) nuclear magnetic resonance. In both blends, the (13)C observed spin was at high concentration, and the (19)F dephasing or probe spin was at low concentration. In this situation, an analysis in terms of a distribution of isolated heteronuclear pairs of spins is valid. Nearest-neighbor separation of (13)C and (19)F labels was determined by accurately mapping the initial dipolar evolution using a shifted-pulse version of REDOR. Based on the results of this experiment, the average distance from a ring-fluorine to the nearest (13)C=O is more than 1.2 A greater than the corresponding CF(3)-(13)C=O distance. Next-nearest and more-distant-neighbor separations of labels were measured in a 416-rotor-cycle constant-time version of REDOR for both blends. Statistically significant local order was established for the nearest-neighbor labels in the methyl-labeled blend. These interchain packing results are in qualitative agreement with predictions based on coarse-grained simulations of a specially adapted model for bisphenol A polycarbonate. The model itself has been previously used to determine static and dynamic properties of polycarbonate with results in good agreement with those from rheological and neutron scattering experiments.
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Affiliation(s)
- Dirk Stueber
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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Stueber D, Mehta AK, Chen Z, Wooley KL, Schaefer J. Local order in polycarbonate glasses by 13
C{19
F} rotational-echo double-resonance NMR. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.20931] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Delle Site L, Leon S, Kremer K. BPA-PC on a Ni111 surface: the interplay between adsorption energy and conformational entropy for different chain-end modifications. J Am Chem Soc 2004; 126:2944-55. [PMID: 14995212 DOI: 10.1021/ja0387406] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We extend a previous dual scale modeling approach for the behavior of polymers near a metal surface to a variety of end groups. Our approach combines a coarse-grained polymer model with ab initio DFT calculations. Such a procedure was applied to a melt of phenolic-like terminated Bisphenol A-polycarbonate (BPA-PC) interacting with a (111) nickel surface (Delle Site, L.; Abrams, C. F.; Alavi, A.; Kremer, K. Phys. Rev. Lett. 2002, 89, 156103. Abrams, C. F.; Delle Site, L.; Kremer, K. Phys. Rev. E 2003, 67, 021807). This work extends this study to different chain-end modifications of BPA-PC, p-tert-butylphenolic, p-tetramethylpropylphenolic, and p-cumylphenolic. We show how the interplay between adsorption energies and conformational entropy selects different morphologies for the various melts at the interface. Implications of these results for realistic technical materials are finally discussed.
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Affiliation(s)
- Luigi Delle Site
- Max-Planck-Institute for Polymer Research, Ackermannweg 10, D 55021 Mainz, Germany.
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Sine-modulated two-dimensional pure exchange solid-state NMR as a tool for characterizing dynamics in solids. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)01186-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kaji H, Fuke K, Horii F. Two-Dimensional 13C Magic Angle Turning NMR Analyses of Dynamics in Poly(2-hydroxypropyl ether of bisphenol A). Macromolecules 2003. [DOI: 10.1021/ma0300342] [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]
Affiliation(s)
- Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Kazunori Fuke
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Fumitaka Horii
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Abrams CF, Delle Site L, Kremer K. Dual-resolution coarse-grained simulation of the bisphenol-A-polycarbonate/nickel interface. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:021807. [PMID: 12636708 DOI: 10.1103/physreve.67.021807] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2002] [Indexed: 05/24/2023]
Abstract
We present a dual-resolution coarse-graining scheme for efficient molecular dynamics simulations of bisphenol-A-polycarbonate (BP-A-PC) liquids in contact with a (111) nickel surface. The essential feature of this model is the strong adsorption of phenoxy chain ends, and the absence of adsorption by other parts of the chains. Details of how phenoxy chain ends interact with the nickel surface were extracted from Car-Parrinello molecular dynamics calculations of adsorption of phenol on nickel. These calculations show that phenol adsorption on nickel is short ranged (<3 A) and strongly dependent on the C1-C4 orientation of the ring. The structure of BP-A-PC prevents internal phenylene groups from interacting with the surface, due to steric hindrances from the noninteracting isopropylidenes. These dependencies are incorporated in the coarse-grained model of the BP-A-PC chain by resolving chain-terminating carbonate groups with atomistic detail, while the rest of the chain is represented by coarsened "beads." This allows specification of the C1-C4 orientation of the terminal phenoxy groups, while overall allowing for system equilibration with reasonable computer time. We simulate liquids of up to 240 chains of ten chemical repeat units, confined in a slit pore formed by two frozen (111) planes of atoms with the lattice spacing of nickel. We find that the strong adsorption of chain ends has a large effect on the liquid structure through a distance of more than two bulk radii of gyration from the surface. These effects are explained by a competition among single- and double-end adsorption, and dense packing. The structure of the interface less than 10 A from the wall is greatly sensitive to the orientational dependence of the phenoxy adsorption.
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Affiliation(s)
- Cameron F Abrams
- Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany.
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van Melick H, Govaert L, Raas B, Nauta W, Meijer H. Kinetics of ageing and re-embrittlement of mechanically rejuvenated polystyrene. POLYMER 2003. [DOI: 10.1016/s0032-3861(02)00863-7] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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O'Connor RD, Poliks B, Bolton DH, Goetz JM, Byers JA, Wooley KL, Schaefer J. Chain Packing in Linear Phenol−Polycarbonate by 13C{2H} REDOR. Macromolecules 2002. [DOI: 10.1021/ma010919i] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert D. O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Barbara Poliks
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Daniel H. Bolton
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jon M. Goetz
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jeffery A. Byers
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Karen L. Wooley
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
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Wu J, Xiao C, Yee AF, Goetz JM, Schaefer J. Local Chain Dynamics in Poly(fluorocarbonate)s. Macromolecules 2000. [DOI: 10.1021/ma0006981] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tekely P, Reichert D, Zimmermann H, Luz Z. Initial conditions for carbon-13 MAS NMR 1D exchange involving chemically equivalent and inequivalent nuclei. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2000; 145:173-183. [PMID: 10910685 DOI: 10.1006/jmre.2000.2092] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A major problem in dynamic 1D (13)C MAS NMR concerns the exchange between magnetically inequivalent, but chemically equivalent sites, whose signals are not resolved in the regular 1D spectrum. This difficulty may be overcome by properly preparing the initial nonequilibrium state of the spin system in the exchange experiments. In the present paper we discuss the advantages and limitations of several such experiments already in use and propose a new sequence, which we term SELDOM-ODESSA. Unlike the other 1D-exchange methods, this experiment yields pure absorption spectra that can more readily be analyzed quantitatively. The experiment is a hybrid comprising a SELDOM sequence, for selective excitation of one of the spinning sideband manifolds in the spectrum, followed by the ODESSA sequence, which induces alternate polarization in the excited sideband manifold. The evolution of the spectrum following this sequence provides information on both the exchange between congruent sites belonging to the same group of equivalent nuclei, and the exchange between inequivalent sites. Results are presented for a tropolone sample specifically enriched in carbon-13 at the carbonyl and hydroxyl sites. The dominant exchange mechanism in this sample involves spin diffusion. The various spin exchange processes in this sample, in the presence and absence of proton decoupling during the mixing time, are measured and discussed. Copyright 2000 Academic Press.
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Affiliation(s)
- P Tekely
- Laboratoire de Methodologie RMN, UPRESA CNRS 7042, Universite Henri Poincare, Nancy 1, Vandoeuvre-les-Nancy, 54506, France
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Kaji H, Schmidt-Rohr K. Conformation and Dynamics of Atactic Poly(acrylonitrile). 1. Trans/Gauche Ratio from Double-Quantum Solid-State 13C NMR of the Methylene Groups. Macromolecules 2000. [DOI: 10.1021/ma0002592] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hironori Kaji
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003
| | - Klaus Schmidt-Rohr
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003
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deAzevedo ER, Bonagamba TJ, Schmidt-Rohr K. Pure-exchange solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2000; 142:86-96. [PMID: 10617438 DOI: 10.1006/jmre.1999.1918] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Three exchange nuclear magnetic resonance (NMR) techniques are presented that yield (13)C NMR spectra exclusively of slowly reorienting segments, suppressing the often dominant signals of immobile components. The first technique eliminates the diagonal ridge that usually dominates two-dimensional (2D) exchange NMR spectra and that makes it hard to detect the broad and low off-diagonal exchange patterns. A modulation of the 2D exchange spectrum by the sine-square of a factor which is proportional to the difference between evolution and detection frequencies is generated by fixed additional evolution and detection periods of duration tau, yielding a 2D pure-exchange (PUREX) spectrum. Smooth off-diagonal intensity is obtained by systematically incrementing tau and summing up the resulting spectra. The related second technique yields a static one-dimensional (1D) spectrum selectively of the exchanging site(s), which can thus be identified. Efficient detection of previously almost unobservable slow motions in a semicrystalline polymer is demonstrated. The third approach, a 1D pure-exchange experiment under magic-angle spinning, is an extension of the exchange-induced sideband (EIS) method. A TOSS (total suppression of sidebands) spectrum obtained after the same number of pulses and delays, with a simple swap of z periods, is subtracted from the EIS spectrum, leaving only the exchange-induced sidebands and a strong, easily detected centerband of the mobile site(s).
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Affiliation(s)
- E R deAzevedo
- Department of Polymer Science & Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
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