Author: J.L.S. Wales
Publisher: Springer
ISBN: 9789029801027
Category : Science
Languages : en
Pages : 111
Get Book Here
Book Description
1. 1 Preamble The science to which this work is appended is termed rheology and rheology means the study of flow and deformation of liquids and solids with emphasis on the underlying physical processes. Characteristic for solids is that they respond to a force by deforming, and, on removal of the force, by returning to their original shape. This type of re sponse is termed elastic. Characteristic for liquids is that they deform and continue to deform as long as the force is present. This type of response is termed viscous. The two definitions just given for viscous and elastic response represent ~wo extremes of response to an external force. Materials do not always fall readily into one or the other of the above-mentioned categories. An additional parameter is needed to describe material response more fully. The extra param eter is time. As a general rule the faster the deformation the closer the re sponse is to being elastic, the slower the deformation the closer the response is to being viscous. Slow and fast . are factors relative to some natural time, T, of the material. This natural time may be thought connected with the rates of spontaneous diffusion of its molecular and atomic constituents. For every day fluids as water, the natural time is very short, of the order of 10-10s 1) and hence for most purposes is considered as being viscous.
Author: J.L.S. Wales
Publisher: Springer
ISBN: 9789401015561
Category : Science
Languages : en
Pages : 0
Get Book Here
Book Description
1. 1 Preamble The science to which this work is appended is termed rheology and rheology means the study of flow and deformation of liquids and solids with emphasis on the underlying physical processes. Characteristic for solids is that they respond to a force by deforming, and, on removal of the force, by returning to their original shape. This type of re sponse is termed elastic. Characteristic for liquids is that they deform and continue to deform as long as the force is present. This type of response is termed viscous. The two definitions just given for viscous and elastic response represent ~wo extremes of response to an external force. Materials do not always fall readily into one or the other of the above-mentioned categories. An additional parameter is needed to describe material response more fully. The extra param eter is time. As a general rule the faster the deformation the closer the re sponse is to being elastic, the slower the deformation the closer the response is to being viscous. Slow and fast . are factors relative to some natural time, T, of the material. This natural time may be thought connected with the rates of spontaneous diffusion of its molecular and atomic constituents. For every day fluids as water, the natural time is very short, of the order of 10-10s 1) and hence for most purposes is considered as being viscous.
Author: Hermann Janeschitz-Kriegl
Publisher: Springer Science & Business Media
ISBN: 3642688225
Category : Technology & Engineering
Languages : en
Pages : 538
Get Book Here
Book Description
The present monograph is intended as an introduction into a field which certainly did not receive proper attention in the past. It is one of the aims of this book to verify this suppo sition. The author hopes to show that the technique of the measurement of flow birefringence can fulfil an important com plementary task in polymer melt rheology. From this point it is expected that the present monograph will attract the atten tion of polymer scientists in general, and of rheologists and process engineers in particular. Certainly, the fourth chapter will appeal to the latter group. As a teacher in polymer science and technology the author wants to address also the group of the graduate students. In fact, the standard knowledge acquired during usual university studies in chemistry, physics or engineering does not enable a quick start of research activities in the field of polymer melt rheology. Certainly, in this typically interdisciplinary field everyone can lay emphasis on matters which are familar to hirn because of his preceding education. Significant research activities, however, can only be generated on the basis of a more universal knowledge. In the absence of this knowledge beginners have to rely upon the guidance of their supervisors for an unduly long period. Otherwise they take the risk of losing too much of their costly time. This holds in particular for the experimentalists who cannot be dispensed from being familiar with the necessary theoretical background.
Author: R.S. Lenk
Publisher: Springer Science & Business Media
ISBN: 940109666X
Category : Science
Languages : en
Pages : 380
Get Book Here
Book Description
Everything flows, so rheology is a universal science. Even if we set aside claims of such width, there can be no doubt of its importance in polymers. It joins with chemistry in the polymerisation step but polymer engineering is supreme in all the succeeding steps. This is the area concerned with the fabrication of the polymer into articles or components, with their design to meet the needs in service, and with the long and short term performance of the article or component. This is a typical area of professional engineering activity, but one as yet without its proper complement of professional engineers. An understanding of polymer rheology is the key to effective design and material plus process selection, to efficient fabrication, and to satisfactory service, yet few engineers make adequate use of what is known and understood in polymer rheology. Its importance in the flow processes of fabrication is obvious. Less obvious, but equally important, are the rheological phenomena which determine the in-service performance. There is a gap between the polymer rheologist and the polymer engineer which is damaging to both parties and which contributes to a less than satisfactory use of polymers in our society. It is important that this gap be filled and this book makes an attempt to do so. It presents an outline of what is known in a concise and logical fashion. It does this starting from first principles and with the minimum use of complex mathematics.
Author: H. Janeschitz-Kriegl
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: F N Cogswell
Publisher: Elsevier
ISBN: 0857092987
Category : Science
Languages : en
Pages : 195
Get Book Here
Book Description
This book explores the ways in which melt flow behaviour can be exploited by the plastics engineer and technician for increased efficiency of processing operation, control of end product properties and selection and development of polymers for specific purposes. (reissued with minor corrections 1994)
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 111
Get Book Here
Book Description
Author: J. A. Brydson
Publisher:
ISBN:
Category : Polymer melting
Languages : en
Pages : 250
Get Book Here
Book Description
Author: Ramesh Mani Subramanian
Publisher:
ISBN: 9780315969469
Category : Refraction, Double
Languages : en
Pages : 482
Get Book Here
Book Description
Author: John M Dealy
Publisher: Springer Science & Business Media
ISBN: 9400763956
Category : Technology & Engineering
Languages : en
Pages : 311
Get Book Here
Book Description
This is the second edition of Melt Rheology and its Role in Plastics Processing, although the title has changed to reflect its broadened scope. Advances in the recent years in rheometer technology and polymer science have greatly enhanced the usefulness of rheology in the plastics industry. It is now possible to design polymers having specific molecular structures and to predict the flow properties of melts having those structures. In addition, rheological properties now provide more precise information about molecular structure. This book provides all the information that is needed for the intelligent application of rheology in the development of new polymers, the determination of molecular structure and the correlation of processability with laboratory test data. Theory and equations are limited to what is essential for the use of rheology in the characterization of polymers, the development of new plastics materials and the prediction of plastics processing behavior. The emphasis is on information that will be of direct use to practitioners. Extensive references are provided for those wishing to pursue certain issues in greater depth. While the primary audience is applied polymer scientists and plastics engineers, the book will also be of use to postgraduate students in polymer science and engineering and as a text for a graduate course.
