Nano- and Mircro- Mechanics of Polymer Blends and Composites

610 Pages·20.217 MB·610\610

by  József Karger-Kocsis and Stokyo Fakirov (Eds.)

Karger-Kocsis, Fakirov
Nano- and Micromechanics of
Polymer Blends and Composites
József Karger-Kocsis
Stoyko Fakirov
Nano- and Micro-
mechanics of Polymer
Blends and Composites
Hanser Publishers, Munich Hanser Publications, Cincinnati
The Editors:
Prof. Dr.-Ing. József Karger-Kocsis, Department of Polymer Engineering, Faculty of Mechanical
Engineering, Budapest University of Technology and Economics, 1111 Budapest, Hungary
Prof. Stoyko Fakirov, Ph.D., The University of Auckland, Department of Mechanical Engineering, Private
bag 92019, Auckland, New Zealand
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Library of Congress Cataloging-in-Publication Data
Nano- and micromechanics of polymer blends and composites / edited by Jszsef
Karger-Kocsis, and Stoyko Fakirov.
p. cm.
Includes bibliographical references.
Summary: „The aim of this book is to give a state-of-art overview on
aspects of micro- and nanomechanics of polymers, polymeric blends and
composites“--Provided by publisher.
ISBN 978-1-56990-435-0
1. Polymeric composites--Mechanical properties. 2. Micromechanics. 3.
Microstructure. 4. Nanostructured materials. I. Fakirov, Stoyko. II.
Karger-Kocsis, J. (Jszsef)
TA455.P58N355 2009
620.1‘920423--dc22
2009010703
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Preface
The deduction of structure-property relationships is a major target of materials
scientists. Unfortunately, these relationships are hardly ever universal, but mostly
of specific nature. On the one hand, this is due to the fact that there is no
correlation between the structural units in different materials, such as metals,
ceramics and polymers. On the other hand, the materials have a very complex
structural build-up, the constituents of which are strongly interrelated. This note
holds especially for polymers.
Depending on the size of the volume elements which contain all structural
“inhomogeneities” in a way that via their combination the related material can
be treated as “homogenous” (representative volume element concept), one may
distinguish between macro-, micro- and nanocomposites. The size of the represen-
tative volume element in macrocomposites is in the range of millimeters and above.
Such polymer macrocomposites, as those with various textile architecture (woven,
braided), resin infiltrated open cell metallic and ceramic foams etc., are beyond
the scope of this book. The term polymer microcomposite covers very different
systems, accepting the definition that at least one dimension of the constituents
is in the micrometer range. So, unidirectional aligned carbon (diameter 6–7 μm)
or glass (diameter 10–15 μm) fiber reinforced composites, neat polymers with
injection molding-induced skin-core structure (oriented skin layer thickness is
usually less then 200 μm), polymer blends and reinforced/filled polymers having
microscale inclusions (at least in one dimension again!) – all belong to this
category. In the case of nanocomposites, at least one dimension of the constituents
should be on the nanoscale (such as clay or carbon nanotubes). As mentioned
above, the structure of polymers may be very complex and multiscaled. For
example, fiber-reinforced microcomposites with a nanomodified matrix or semi-
crystalline polymers themselves (just consider the mean sizes of spherulites and
crystalline lamellae) are on the borderline between micro- and nanocomposites.
This may be the reason why polymer scientists often use the term morphology
instead of micro- and nano-scale structures for neat polymers.
The structural elements of one-component multiphase systems (homopolymers
and copolymers) are in the same size-range as nano- and micro-sized additives
and reinforcements of the multicomponent systems (blends and composites). This
fact makes possible the application of the same characterization techniques and
modeling approaches to these rather different, from material point of view,
systems. What is more, the structural elements in the homopolymers and copoly-
mers as well as the constituents of the blends and composites are distinguished
by their individual mechanical characteristics and each of them makes its own
contribution to the overall mechanical behavior of the whole system. At the same
time, multicomponent systems, as a rule, can be considered multiphase systems
as well. Only in rare cases, when a particular property obeys the additivity law,
the complex system can be easily predicted with respect of this property. In the
rest of the cases, empirical approaches and modeling have to be applied for the
deduction of structure-properties relationships.
With the appearance of polymeric nanocomposites, the structural build-up
of polymeric materials, including polymeric microcomposites, has become even
more complex. This has forced the researchers to check whether or not the know-
ledge acquired with traditional microcomposites can be transferred to nanocom-
posites, produced by different methods. As the reader will notice, this is sometimes
the case for structural polymeric micro- and nanocomposites. On the other hand,
polymer nanocomposites may show peculiar properties that are not present, not
even in analogy, in microcomposites. To find the cause of such behavior is a very
challenging task, which requires a multiscale approach. The latter covers in-depth
structural investigations as well as molecular modeling using different approaches
and techniques.
Our aim with this book is to demonstrate that the multiscale approach is
the right tool for a deeper understanding of the structure-property relationships
in polymeric micro- and nanocomposites. The term “mechanics” in the title is
foreseen to demonstrate that emphasis has been put on structural instead of func-
tional composites. Note that the mechanical behavior of structural composites
is of great practical relevance and the driving force of their development now-
adays. The book contributions are grouped in 5 sections. Part I is devoted to
polymers (Galeski and Regnier and Ginzburg et al.). Part II highlights selected
aspects of composite production (Zhang et al., Bokobza, and Bhattacharyya and
Fakirov). Part III considers interphase aspects (Kalfus and Jancar). Part IV gives
an overview of characterization methods and properties, including in situ deforma-
tion (Stribeck), creep and fatigue (Pegoretti), deformation and fracture properties
(Tjong, Dasari et al. and Karger-Kocsis), and hardness (Fakirov). The book ends
with Part V dealing with modeling of rubber and polymer nanocomposites (Mark
et al. and Spencer and Sweeney).
Our intention was to cover all kinds of polymeric materials, viz. thermoplas-
tics, thermosets, and rubbers, including their different types and combinations.
We are thankful to our contributors for their high quality chapters and their
timely delivery. We strongly hope that you, the readers, will find this book useful
for your work.
A.m.D.g., March, 2009 József Karger-Kocsis
Budapest, Kaiserslautern, Pretoria,
Stoyko Fakirov
Auckland
Content
PART I POLYMERS
Chapter 1 Nano- and Micromechanics
of Crystalline Polymers
A. Galeski, G. Regnier
1.1. Introduction..........................................................................................3
1.2. Tensile deformation of crystalline polymers...........................................4
1.3. Cavitation in tensile deformation..........................................................4
1.4. Tensile deformation of polyethylene and polypropylene........................8
1.5. Deformation micromechanisms in crystalline polymers........................13
1.6. Molecular mechanisms at a nanometer scale.......................................16
1.7. Dislocations in crystal plasticity..........................................................23
1.8. Generation of dislocations...................................................................25
1.9. Competition between crystal plasticity and cavitation........................34
1.10. Micromechanics modeling in semicrystalline polymers.........................35
1.10.1. Microstructure and mechanical properties...................................35
1.10.2. The micromechanical models.......................................................36
1.10.3. Idealizing the microstructure of semicrystalline polymers ............38
1.10.4. Elastic behavior prediction..........................................................40
1.11. Large deformations and bottlenecks....................................................45
1.12. Phenomenological models of polymer deformation
under tensile and compressive stresses ................................................45
1.13. Conclusions.........................................................................................47
References...........................................................................................48
viii Content
Chapter 2 Modeling Mechanical Properties
of Segmented Polyurethanes
V. V. Ginzburg , J. Bicerano, C. P. Christenson,
A. K. Schrock, A. Z. Patashinski
2.1. Introduction........................................................................................59
2.2. Predicting Young’s modulus of segmented polyurethanes...................63
2.2.1. Relationship between Young’s modulus
and formulation – experimental observations..............................63
2.2.2. Theory ........................................................................................64
2.2.3. Young’s modulus: comparing theory with experiments................72
2.3. Modeling tensile stress-strain behavior................................................76
2.4. Linear viscoelasticity...........................................................................82
2.5. Non-equilibrium factors and their influence on mechanical properties 84
2.6. Conclusions and Outlook....................................................................84
Acknowledgment ................................................................................85
References...........................................................................................85
PART II NANOCOMPOSITES:
INFLUENCE OF PREPARATION
Chapter 3 Nanoparticles/Polymer Composites:
Fabrication and Mechanical Properties
M. Q. Zhang, M. Z. Rong, W. H. Ruan
3.1. Introduction........................................................................................93
3.2. Dispersion-oriented manufacturing of nanocomposites........................95
3.2.1. Conventional two-step manufacturing ........................................95
3.2.2. Specific two-step manufacturing ............................................... 107
3.2.3. One-step manufacturing............................................................ 118
3.3. Dispersion and filler/matrix interaction-oriented
manufacturing of nanocomposites..................................................... 120
3.3.1. Two-step manufacturing in terms of in situ reactive
compatibilization....................................................................... 120
3.3.2. One-step manufacturing in terms of in situ graft
and crosslinking......................................................................... 124
3.4. Dispersion, filler/filler interaction and filler/matrix
interaction-oriented manufacturing of nanocomposites..................... 129
3.5. Conclusions....................................................................................... 135
Acknowledgements ........................................................................... 136
References......................................................................................... 136
Content ix
Chapter 4 Rubber Nanocomposites:
New Developments, New Opportunities
L. Bokobza
4.1. Introduction...................................................................................... 141
4.2. General considerations on elastomeric composites............................. 142
4.3. Spherical in situ generated reinforcing particles................................ 144
4.4. Carbon nanotube-filled rubber composites........................................ 153
4.5. Conclusions....................................................................................... 161
References......................................................................................... 162
Chapter 5 Organoclay, Particulate and Nanofibril
Reinforced Polymer-Polymer
Composites: Manufacturing,
Modeling and Applications
D. Bhattacharyya, S. Fakirov
5.1. Introduction...................................................................................... 167
5.2. Polypropylene/organoclay nanocomposites: experimental
characterisation and modeling .......................................................... 169
5.2.1. Peculiarities of polymer/clay nanocomposites............................ 169
5.2.2. Parametric study and associated properties
of PP/organoclay nanocomposites ............................................ 171
5.2.3. Evaluation of the experimental data by means
of Taguchi and Pareto ANOVA methods.................................. 174
5.2.4. Materials, manufacturing and characterisation
of nanocomposites..................................................................... 178
5.2.5. Analytical models for composites............................................... 179
5.2.6. Comparisons of experimental results with the calculated values 182
5.3. The dispersion problem in the case of polymer-polymer
nanocomposites................................................................................. 185
5.3.1. Manufacturing of nanofibrillar polymer-polymer composites..... 187
5.3.2. Nanofibrillar vs. microfibrillar polymer-polymer
composites and their peculiarities.............................................. 188
5.4. Directional, thermal and mechanical characterisation
of polymer-polymer nanofibrillar composites..................................... 190
5.4.1. Directional state of NFC as revealed by wide-angle
X-ray scattering ........................................................................ 190
5.4.2. Thermal characterization of NFC ............................................. 192
5.4.3. Mechanical properties of NFC................................................... 193
5.5. Potentials for application of nanofibrillar composites
and the materials developed from neat nanofibrils............................ 196
x Content
5.6. Conclusions and outlook................................................................... 199
Acknowledgments............................................................................. 200
References......................................................................................... 201
PART III NANO- AND MICROCOMPOSITES:
INTERPHASE
Chapter 6 Viscoelasticity of Amorphous
Polymer Nanocomposites
with Individual Nanoparticles
J. Kalfus
6.1. Introduction...................................................................................... 209
6.2. Brief physics of amorphous polymer matrices.................................... 210
6.2.1. Equilibrium structure of amorphous chains............................... 210
6.2.2. Microscopic relaxation modes and segmental mobility............... 212
6.2.3. Entropy vs. energy driven mechanical response......................... 214
6.3. Basic aspects of amorphous polymer nanocomposites ....................... 216
6.3.1. Structure of surface adsorbed chains......................................... 217
6.3.2. Segmental immobilization of chains in the presence
of solid surfaces......................................................................... 219
6.4. Reinforcement of amorphous nanocomposite
below and above matrix T ............................................................... 222
g
6.5. Strain induced softening of amorphous polymer nanocomposites...... 228
6.6. Relaxation of chains in the presence of nanoparticles ....................... 233
6.7. Conclusions and outlook................................................................... 235
Acknowledgements ........................................................................... 236
References......................................................................................... 236
Chapter 7 Interphase Phenomena in Polymer
Micro- and Nanocomposites
J. Jancar
7.1. Introduction...................................................................................... 241
7.2. Micro-scale interphase in polymer composites................................... 246
7.3. Nano-scale interphase ....................................................................... 250
7.4. Chain immobilization on the nano-scale ........................................... 252
7.5. Characteristic length-scale in polymer matrix nanocomposites.......... 255
7.6. Conclusions and outlook................................................................... 257
Acknowledgement............................................................................. 258
References......................................................................................... 258
Content xi
PART IV NANO- AND MICROCOMPOSITES:
CHARACTERIZATION
Chapter 8 Deformation Behavior of Nanocomposites
Studied by X-Ray Scattering:
Instrumentation and Methodology
N. Stribeck
8.1. Introduction...................................................................................... 269
8.2. Scattering theory and materials structure......................................... 272
8.2.1. Relation between a CDF and IDFs........................................... 275
8.3. Analysis options derived from scattering theory................................ 276
8.3.1. Completeness – a preliminary note............................................ 276
8.3.2. Analysis options ........................................................................ 276
8.3.3. Parameters, functions and operations ....................................... 277
8.4. The experiment................................................................................. 278
8.4.1. Principal design......................................................................... 278
8.4.2. Engineering solutions ................................................................ 279
8.4.3. Scattering data and its evaluation............................................. 284
8.5. Techniques: Dynamic vs. stretch-hold............................................... 286
8.6. Advanced goal: Identification of mechanisms.................................... 286
8.7. Observed promising effects from stretch-hold experiments................ 289
8.7.1. Orientation of nanofibrils in highly oriented
polymer blends by means of USAXS......................................... 289
8.7.2. USAXS studies on undrawn and highly drawn
PP/PET blends........................................................................ 291
8.8. Choosing experiments....................................................................... 293
8.8.1. Experiments with a macrobeam................................................ 293
8.8.2. Experiments with a microbeam................................................. 294
8.9. Conclusion and outlook .................................................................... 295
References......................................................................................... 296
Chapter 9 Creep and Fatigue Behavior
of Polymer Nanocomposites
A. Pegoretti
9.1. Introduction...................................................................................... 301
9.2. Generalities on the creep behavior of viscoelastic materials............... 302
9.3. Generalities on the fatigue resistance of polymeric materials............. 306
9.4. Creep behavior of polymer nanocomposites ...................................... 309
9.4.1. Creep response of PNCs containing
one-dimensional nanofillers........................................................ 309