Structure and Dynamics of Bulk Polymers by NMR-Methods

In recent years the development of the NMR method has been closely linked to the creation of the theory of the NMR in solids and with the elaboration on their basic principles and methods of high resolution in solids. The aim of this volume is to explain simply and clearly the principles for the understanding of the NMR in solid polymers, to show what kind of information can be gained using NMR investigations of bulk polymers, and to demonstrate the ways of obtaining this information, their correctness and their place in comparison with other methods. The discussion is restricted to the most important and typical nuclei 1H, 13C, and (briefly) 2D, and, in connection with that, to the dipolar and quadrupolar interaction and to the chemical shift.

1 Theoretical Aspects.- 1.1 Line Shape and Transverse Relaxation in Solids.- 1.1.1 Dipole Interaction.- 1.1.2 Chemical Shift.- 1.1.3 Quadrupolar Interaction.- 1.1.4 Line Narrowing in Solids.- 1.2 Spin-Dynamics and Longitudinal Relaxation.- 1.2.1 Spin Temperature.- 1.2.2 Spin Diffusion.- 1.2.3 Spin-Flip Effects.- 1.2.4 Spin-Locking Experiment.- 1.2.5 Multipulse Spin-Locking.- 1.2.6 Cross-Polarization and Nuclear-Overhauser Effect.- 1.3 Effect of Molecular Motion.- 1.3.1 General Remarks on the Form of the Correlation Function.- 1.3.2 Two Approaches to the Analysis of Motional Effects.- 1.3.3 Model-free Approach.- 1.3.4 Correlation Functions for Some Motional Models.- 1.3.5 Quadrupolar Line Shape under the Influence of Molecular Motion.- 2 Experiment.- 2.1 Pulse Methods.- 2.1.1 Nonselective Methods.- 2.1.2 Selective Methods in Solids.- 2.2 Methods of Heterogeneous Analysis.- 2.2.1 Signal Decomposition.- 2.2.2 Two-Dimensional Analysis in Time Domain.- 2.2.3 Two-Dimensional Spectroscopy.- 3 NMR Signal Shape and Polymer Structure.- 3.1 Transverse Magnetization of Protons.- 3.1.1 Experiments.- 3.1.2 Analysis of the Experiments in Semicrystalline Polymers.- 3.1.3 Nature of the Approximating Functions in the Solid State.- 3.1.4 Approximating Functions and Semiquantitative Description of Experiments in Polymer Liquids.- 3.1.5 Connection Between the Signal Parameters and the Polymer Network Structure.- 3.2 Longitudinal Magnetization of Protons.- 3.2.1 Signal Decomposition in Amorphous Polymers and Spin-Dynamics Effects.- 3.2.2 Analysis of Signals in Amorphous Polymers with Molecular Heterogeneities.- 3.2.3 Signal Analysis in Semicrystalline Polymers.- 3.2.4 Comparative Analysis of the Experiments on Pulse and Continuous Spin-Locking.- 3.3 Line Shape Analysis for 13C- and 2H-Spectra.- 3.3.1 Shielding Tensor Distribution in Isotropic Polymers.- 3.3.2 Oriented Polymers.- 3.3.3 Further Methods for the Determination of the Polymer Structure.- 3.3.4 Methods for the Reestablishment of Anisotropy Parameters in Polymers.- 3.4 Improvement of the Structural Information by Different Techniques.- 3.4.1 Suppression of Parts of the Spectrum by the Use of the Differences in the Relaxation Times.- 3.4.2 Consequences for 13C Cross-Polarization Measurements.- 3.4.3 Selective Deuteration.- 3.5 Highly Resolved 13C-Spectra in Solid Polymers.- 3.5.1 General Considerations.- 3.5.2 Connections between the Molecular Structure and the Spectra.- 3.5.3 Typical Applications.- 4 Molecular Motion in Bulk Polymers.- 4.1 Amorphous Polymers.- 4.1.1 Local Motion of the Backbone.- 4.1.2 Motion of Side- and End Groups.- 4.1.3 Segmental Motion.- 4.1.4 Special Applications of 2H NMR.- 4.2 Molecular Motion and Relaxation Transitions in Solid Polyethylene.- 4.2.1 Qualitative Analysis of the Experiments and Attribution of the Relaxation Transitions.- 4.2.2 Determination of the Microdynamic Parameters.- 4.2.3 Discussion from the Viewpoint of the Models of Molecular Motion.- 4.2.4 Connection between Molecular Motion and Structure in PE.- 5 Special Polymer Systems and Phenomena.- 5.1 Relaxation Times and Mechanical Properties.- 5.2 Translational Motion of Macromolecules.- 5.3 Multicomponent Polymer Systems.- 5.3.1 General Considerations.- 5.3.2 Some Methodical Aspects.- 5.3.3 Other Applications.- 5.4 Molecular Motion in Globular Proteins.- 5.4.1 Selective NMR Experiments in Solutions.- 5.4.2 Non-Selective NMR Experiments.- References.