Doctoral theses
Search command : Author="Κωνσταντινίδης"
And Author="Κ."
And Author="Θεόδωρος"
Current Record: 48 of 81
|
Identifier |
000407884 |
Title |
Development of protocols for investigating linear branched and supramolecular polymers undergoing shear |
Alternative Title |
Ανάπτυξη πρωτοκόλλων για την διερεύνηση γραμμικών διακλαδωμένων και υπερμοριακών πολυμερών υπό την επίδραση διάτμησης |
Author
|
Costanzo, Salvatore
|
Thesis advisor
|
Βλασσόπουλος, Δημήτριος
|
Reviewer
|
Πετεκίδης, Γεώργιος
Benoit, Loppinet
Χαρμανδάρης, Ευάγγελος
Βαμβακάκη, Μαρία
van Ruymbeke Evelyne
Iannituberto, Giovanni
|
Abstract |
The aim of the present thesis is to shed light into the nonlinear rheological behavior of complex polymeric structures by means of state-of-the-art instrumentation, particularly focusing on shear rheology. Strong nonlinear flows are ubiquitous in polymer processing, therefore their understanding is fundamental for technological applications. On the other hand, the progress in nonlinear rheology has been halted by experimental issues associated with flow instabilities, rendering rheometric experiments problematic. The development of experimental tools to resolve these issues is a timely, outstanding challenge. Overcoming flow instabilities in nonlinear experimental rheology will advance the field in different directions such as accurate modeling development, decoding molecular mechanisms of motion, designing macromolecular systems with desired, tunable properties. Particularly, in relation to molecular mechanisms, knowledge of polymer
dynamics in nonlinear flows is rather limited, especially in shear. In such a context, this thesis work attempts to answer two key questions: i) How can we obtain reliable measurements in transient shear? ii) What is the interplay of entanglements, branching and associations in determining the nonlinear rheology of complex systems? It is clear that answering the first question is necessary in order to address the second one.
Therefore, in the first part of this thesis we present the design and implementation of acone-partitioned-plate (CPP) geometry for ARES rheometer that allows for accurate, artifact-free measurements in nonlinear transient shear. In the second part, we apply CPP and uniaxial extensional rheometry to investigate model systems including linear, ring, Cayley-tree and dendronized polymers, in order to address the above-mentioned
questions.
|
Language |
English |
Subject |
Uniaxial extension |
|
Κόνου διερεμένης πλάκας |
Issue date |
2017-11-24 |
Collection
|
School/Department--School of Sciences and Engineering--Department of Materials Science and Technology--Doctoral theses
|
|
Type of Work--Doctoral theses
|
Permanent Link |
https://elocus.lib.uoc.gr//dlib/7/3/5/metadata-dlib-1500296611-345948-2679.tkl
|
Views |
621 |