Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
PRESSURE-TEMPERATURE NMR STUDIES OF POLYMER AND DISORDERED CRYSTALLINE SYSTEMS
Author: Scientific and Technical Aerospace Reports
Author: High Pressure Nmr Studies of Disordered Solids and Polymers
Author: Dissertation Abstracts International
Author: Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 794
Book Description
NMR Study of Disordered Materials Under Extreme Conditions of Pressure and Temperature
Author: Jiri JonasPublisher:
ISBN:
Category :
Languages : en
Pages : 20
Book Description
A new NMR method for measuring the crystallization kinetics of polymers under high pressure, sensitive on a molecular scale to the dynamics of chain motion, was developed. The very rapid formation of extended chain crystals of polyethylene was directly observed. The techniques has much promise for future experiments including polymer crystallization, melting and annealing. Polarization microscopy and NMR experiments on various alkali salts of alkalicarboxylates elucidated the dynamic structure of the smectic phase of these interesting ionic liquid crystalline materials. Experiments on highly viscous liquids explained the origin of the anomalous discontinuity observed in the temperature dependence of the shear viscosity of glass forming liquids. Molecular level interpretation of the coupling between translational and rotational motions in viscous liquids was chieved. The Debye and Stokes-Einstein equations were found to be applicable at the molecular level in viscous liquids. Volume effects were shown to be important for dynamics of viscous liquids.
Solid State NMR of Polymers
Author: T. AsakuraPublisher: Elsevier
ISBN: 0080541461
Category : Science
Languages : en
Pages : 1017
Book Description
In polymer science and technology, the advanced development of various new polymer materials with excellent properties and functions is desirable. For this purpose it is necesary to determine the exact relationship between physical properties and molecular structure-dynamics with powerful techniques. One such technique is solid state NMR. Recently, high resolution NMR studies of solids have been realized by using advanced pulse and mechanical techniques, which has resulted in a variety of structural and dynamical information on polymer systems. Solid state NMR has provided characteristic information which cannot be obtained by other spectroscopic methods. This book is divided into two parts. The first part covers the principles of NMR, important NMR parameters such as chemical shifts, relaxation times, dipolar interactions, quadrupolar interactions, pulse techniques and new NMR methods. In the second part, applications of NMR to a variety of polymer systems in the solid state are described. Features of this book: • Contains an up-to-date and comprehensive account of solid state NMR of polymers by leading researchers in the field • Provides a compilation of solid state NMR of polymers, which makes it an ideal reference book for both NMR researchers and general polymer scientists. This book will be of interest to the NMR community, and will be invaluable for both the beginner and the expert.
NMR Studies of Entangled Polybutadiene Networks, Polymer Crystallization at High Pressure, and Kaolinite-water Systems at High Pressure
Author: Donald Ray BrownAb Initio Calculations of Conformational Effects on 13C NMR Spectra of Amorphous Polymers
Author: R. BornPublisher: Springer Science & Business Media
ISBN: 364260644X
Category : Technology & Engineering
Languages : en
Pages : 132
Book Description
In NMR, it is well-known that the chemical shift conveys structural informa tion, e. g. a carbonyl carbon will have a resonance frequency appreciably dif ferent from a methyl carbon, etc. The relation between structure and chemical shift is mostly established by empirical rules on the basis of prior experience. It is only quite recently that the advent of both comparatively cheap comput ing power and novel quantum chemistry approaches have provided feasible routes to calculate the chemical shift at the ab initio level for molecules of reasonable size. This raises the question whether application of these novel theoretical concepts offers a means of obtaining new structural information for the complex chain molecules one deals with in polymer science. Solid state 13C-NMR spectra of glassy amorphous polymers display broad, partially structured resonance regions that reflect the underlying disorder of the polymer chains. The chemical shift responds to the variation of the ge ometry of the chain, and the broad resonance regions can be explained by an inhomogeneous superposition of various chain geometries (and thus chem ical shifts). In this review, we present a novel approach to combine polymer chain statistical models, quantum chemistry and solid state NMR to pro vide quantitative information about the local chain geometry in amorphous polymers. The statistical model yields the relative occurrence of the various geometries, and quantum chemistry (together with a force field geometry op timization) establishes the link between geometry and chemical shift.
High Pressure 13c Nmr Studies of Dynamics in Disordered Systems
Author: Philip John GrandinettiPublisher:
ISBN:
Category :
Languages : en
Pages : 168
Book Description
Structural Studies of Polymers by Solution Nmr
Author: H.N. ChengPublisher: iSmithers Rapra Publishing
ISBN: 9781859572481
Category : Science
Languages : en
Pages : 168
Book Description
Solution-state NMR spectroscopy is generally regarded as the premier technique to characterise polymer structure. This report provides a timely review of the developments in the NMR of polymers in solution in the past few years. An additional indexed section containing several hundred abstracts from the Polymer Library gives useful references for further reading.