HANDBOOK OF· THERMAL ANALYSIS AND CALORIMETRY

VOLUME3 APPLICATIONS TO POLYMERS AND PLASTICS

EDITEDBY

STEPHEN Z.D. CHENG

DEPARTMENT OF POLYMER SCIENCE UNNERSITY OF AKR.ON AKR.ON, OH 44325-3909

USA

2002

ELSEVIER AMSTERDAM- BOS10N - WNDON - NEW YORK- OXFORD - PARIS

SAN DIEGO - SAN FRANOSCO - SINGAPORE - SYDNEY - TOKYO

CONTENTS

Foreword - P.K. Gallagher........................................................... v Preface- S.Z.D. Cheng............................................................... vü Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. xxvü

CHAPTER 1. HEAT CAP ACITY OF POLYMERS (B. Wunderlich)

1. MEASUREMENT OF HEAT CAP ACITY ..... „... .. . . . ... . ... . ... . . ... ... 1

2. THERMODYNAMIC THEORY.... ..... ........ ......... ....... ... .......... 5

3. QUANTUM MECHANICAL DESCRIPTION.... .. . . . . . . . . . . .. . . . . . . . .. . . 5

4. TIIE HEAT CAPACITY OF SOLIDS........................................ 10

5. COMPLEXIIEAT CAPACITY. .............................................. 14

6. TIIE ADV ANCED TIIERMAL ANALYSIS SYSTEM, A TIIAS . . .... 16 6.1. Tue crystallinity dependence ofheat capacity........... .................... 16 6.2. Heat capacities of solids . . ..... ... . . . .. . . .. . . . . . . . . . . . . . . . .. . . .. . . . . .. . . . . .. . ... 18 6.3. Polyoxide heat capacities .... ............. ............................... ...... 25 6.4. Heat capacities of liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7. EXAMPLES OF THE APPLICATION OF A 1HAS.. .. . . . . . . . . . . . . . . . . ... 28 7.1. Poly(tetrafluoroethylene) ...................................................... 28 7.2. Poly(oxybenzoatcxo-oxynaphthoate) .. . . . .. . .. . .. . . . . . . . . . . .. . . . . .. . . . . . . . . 29 7.3. Large-amplitude motion ofpolyethylene .................................... 30 7 .4. Polymethionine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 31 7.5. MBPE-9 .. „...................................................................... 31 7.6. Liquid selenium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 32 7.7. Poly(styrene-co-butadiene) .................................................... 33

8. TEMERATURE-MODULATED CALORIMETRY.. .. . . .. . . . . . . . .. . . . ... 34 8.1 . Heat capacity and glass transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 36 8.2. First-order transitions and chemical reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

9. CONCLUDINGREMARKS................................................... 45

ACKNOWLEOOMENTS . . . . . . . . . . . . . . . . . .. . . . . . . .. . . ... . ... . . . .. ....... .. . . .. . .... 46

REFERENCES. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . ... . . . . . . . .. . . .... 46

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CHAPTER 2. THE GLASS TRANSITION: ITS MEASUREMENT AND UNDERL YING PHYSICS (Gregory B. McKenna and Sindee L. Simon)

1. INTR.ODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. 49

2. THE APP ARENT THERMODYNAMIC BEHA VIOR.. .. . . . . . . . . . ... . .. 50 2.1. Some thermodynamic definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 50 2.2. Time or rate effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52 2.3. Path dependen:e of the PVT surface . . .. . . . . . . . .. . . . . . . . .. . . . . . . . ... . . . . . . ... 54 2.4. Isobaric ( constant pressure) glass formation vs isochoric ( constant

volume) glass formation ....................................................... 55

3. KINETICS OF GLASSFORMATION...................................... 58 3.1. Preliminary comments ......................................................... 58 3.2. Phenomenology of structural recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 59

3.2.1. The asymmetry ofapproach experiment .............................. 60 32.2. The memory or cross-over experiment ............................... 61

3.3. The Tool-Narayanaswamy-Moynihan-Kovacs-Aklonis-Hutchinson Ramos (TNM-KAHR) description of structural recovery . . . . . . . . . . . . . . . .. 62 3.3.1. Strengths and weaknesses ofthe models ............................. 65

3.4. The thermoviscoelastic model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67 3.4.1. Model predictions for volume recovery: comparison with

Kovacs' data............................................................. .. 70 3.4.2. Strengths and weaknesses of the thermoviscoelastic model .. .. . .. 72

3.5. Viscosity and segmental relaxation behavior above the glass transition temperature..................................................................... .. 73

4. MICROSCOPIC THEORIES RELA TED TO THE GLASS TRANSITION.................................................................. 76

4.1. General comrnents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 76 4.2. Free volume models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.3. The Gibbs-DiMarzio configurational entropy model ...................... 78 4.4. Comparison ofthe free volume and configurational entropy models

with experiments.. .. . .. . . . . . . . . . . . .. . . . . . . . ... .. . . . . . . ... ... ... . .. . . . .. . . . . . . . . . 81

5. MEASUREMENT OF Tg .......... .. ........ ....•.•....... ..... ............. ... 81 5.1. General comments ............................................................... 81 5.2. Dilatometric methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 82

5.2.1. Fluid confinement dilatometry ...................................... 82 52.2. Length change dilatometry............................................... 84

5.3. Calorimetric techniques„....................................................... 85

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5.3.1. Differential scanning calori.metry (DSC) ............................. 86 5.3.2. Temperature-modulated differential scanning calorimetry

(TMDSC).................................................................. 92 5.3.3. Dynarnic heat spectroscopy (DHS) . . . . ....... .. . . . . . . . . . . . . . . . ....... 94

6. PHYSICAL AG ING EFFECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 6.1. Linear viscoelastic regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96 6.2. Nonlinear viscoelastic regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 6.3. Engineering properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

6.3.1. Yield strength ............................................................ 101 6.3.2. Failure related properties ............................................... 101 6.3.3. Residual stresses ... ..... ........ ...... ............. .. . ................... 103

7. CONCLUDINGREMARKS ................................................. 104

ACKNOWLEDGMENTS . . ............................................... .. . . . . .... 104

REFERENCES ....................................................................... 104

CHAPTER 3. MECHANICAL RELAXATION PROCESSES IN POLYMERS (S. Matsuoka)

1. WHATDO WE MEAN BY TIIE RELAXATION PROCESS .......... 111 1.1. On the experimental scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 111 1.2. On the molecular scale ......................................................... 116

2. INTERMOLECULAR COOPERATIVITY.. .. . . .......... .. . . . . . . . . . . ..... 119 2.1. Free volume and excess enthalpy in the condensed state .................. 121 2.2. Excess enthalpy that drops faster than the conformational entropy . . . . . . 123

3. CHEMICAL STRUCTURE AND Tg ........•.... „.................... .. . . . 124

4. VISCOELASTICITY DATA ANALYSIS ........ „„ .. „.„......... 127 4.1. Viscoelasticity data analysis near but above Tg ...•... .•... ...•...........•. 127 4.2. Viscoelasticity data analysis of polymer melt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

4.2.1. Polymers in solution ..................................................... 131 4.2.2. Polymers in bulks ........................................................ 137

5. BEYOND LINEAR VISCOELASTICITY . .... ............ ....... ... . . ....... 143

REFERENCES ....................................................................... 145

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CHAPTER 4. DIELECTRIC ANALYSIS OF POLYMERS (Peter Avakian, Howard W. Starkweather, Jr. and William G. Kampert)

1. INTRODUCTION .. „.„„ ... „ ...•.........•.... „ ....•.•..........•....... „. 147

2. POLAR AMORPHOUS POLYMERS „ „. „ „ „ „ „ „ „ „ „ „ „. „. „. „„ 150 2.1. Polymethyl methacrylate (PMMA) ................ „ ....... „.............. .. 150 2.2. Polycarbonate ..................................................... „ •......... „. 152 2.3. Polyamides .. „.„ ....... „.„ ..........•................•............ „ .... „ .• „ 154

3. NONPOLARPOLYMERS „„„„„ .. „.„„„.„„„„ .. „„„„ .. „ .. „... 157 3.1. Hydrocarbonpolymers .......................... „.„ ..•.•................. „.. 157 3.2. Fluoropolymers „ •• „„.„ .... „„„ ........ „.„„„.„ .. „ ... „„.„.„ .•• „„. 158

4. MISCIBILITY OF POLYMER BLENDS .. „ •...... „ ..•. „ ............. „ 159

5. COLD CRYSTALLIZATION OF AMORPHOUS POLYMERS ABOVE Tg „„ ... „„„„„„ .• „.„ „ ..• „„.„„ .. „.„„ .„„„ ... „ .. „„„. 161

6. FREQUENCY-TEMPERATURE RELATIONSIIlPS „.„„.„„ .. „.„ 163

ACKNOWLEOOMEN"TS . „.„. „ ..........•..........• „ ................ „ .... „.. 164

REFERENCES .. „ ... „ ...........•..... „ ............. „ .....•.................. „„ 164

CHAPTER 5. CRYST ALLIZATION AND MELTING OF METASTABLE CRYSTALLINE POLYMERS (Stephen Z. D. Cheng and Shi Jin)

1. INTRODUCTION .... „ ..... „ ........ „ •........ „.„ .... „.„ ............. „. 167

2. THERMODYNAMIC DEFINITIONS OF THE PHASE AND PHASE TRANSITIONS „ .•.... „. „ .•................................ „ „ ..•. „..... .. 167

2.1. Desaiption ofphases .. „„ ..•... „ ... „.„ ........ „.„ ..... „ ..... „„ •.... „. 167 2.2. Definitions ofphase transitions ................. „ ......... „.„ ............. „ 169 2.3. Phase equilibrium and stability ............ „ ... „ .. „ ... „. „ ........... „. „. 172 2.4. Concepts of classi.cal metastable states ........... „ ....... „ .......... „. „„ 173 2.5. Metastable states in polymers . „ ..... „ .......... „ .. „ ... „. „ ........•.... „ 174 3. POLYMERCRYSTALLIZATIONANDMORPHOLOGY „„„„„„ 175 3.1. Isothermal crystallization . „. „ „ .. „ „ ........ „ „. „ „. „ .... „. „ „ „ „ „... 176 3.2. Overall crystalliz.ation rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 3.3. Linear crystal growth rates ..... „„ .... „ .... „ ..•.•. „ ...............•... „... 180

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3.4. Non-isothennal crystalliz.ation ................................................ 181 3.5. Crystalline morphology ......... „.......................................... .... 182

4. POLYMERCRYSTALMELTING ...................................... „ .. 183 4.1. Extrapolations to obtain equilibrium melting properties . . . . . . . . . . . . . . . . . . 184 4.2. Metastability changes in polymer crystal melting ....... „ ............... „ 187 4.3. Interfaces between crystalline and amorphous regions .................. „ 189

5. CONCLUDING REMARKS .„„.„„„ •. „ ..•...•.......•. „ .. „„.„ ..... „ 191

ACKNOWLEOOMENTS ..................................................... „ .. „ 192

REFERENCES .. „ ...•..•.......................•.........•........... „ .......... „. 192

CHAPTER6. CRYSTALLIZATION, MELTING AND MORPHOLOGY OF HOMOGENEOUS ETHYLENE COPOL YMERS (Vincent B. F. Mathot and Harry Reynaers)

1. INTR.ODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......... ... 197

2. ETIIYLENE-PROPYLENE COPOL YMERS ................ „........ ... 200 2.1. Influence of comonomer content on crystalliz.ati.on and melting . . . . . . . . . 200 2.2. Heat capacity, enthalpy, crystallinity, baseline and excess heat capacity 204 2.3. Illustrating the use of the 'extrapolation method' for calculating

crystallinities as applied to 'pseudo heat capacity' measurements on characteristic samples....... .. ..... ....................................... .. . .. 212

2.4. Remarks on the use of the extrapolation method for crystallinity determination .. „............................................................... 212

2.5. Morphology...................... . .. . . . . . . . . . . . . . . . . . . . . . ... . ...... ... . . .. . . . . . .. 213

3. ETIIYLENE-1-BUTENECOPOLYMERS ......................... „..... 219 3.1. lnfluence of comonomer content .. „. „....... ... . ... . . . . . ... .. ..... ..... .. .. 219 3.2. Metastability: influence of cooling rate . . . . . . . . . . . . . . . . . . . . . . . .. .. . . ... . . . ... 221 3.3. Morphology.............. .. . . . . . . . . . . .. . . . . .. . . . . .. . . . . ...... ...... ... . . .... .. .. 222

3.3.l. Metastability: measurements as in temperature modulated calorimetry .. „ .•.......•...•....•.........•.. „ .....•. „ ............. „.. 224

4. ETIIYLENE-1-0CTENE COPOL YMERS „„ „„„. „„„ ..• „„„ .. „ „ 225 4.1. lnfluence of comonomer content for copolymers with densities above

about 870 kg/m3 ••• •••••••••••••••••••••••••••••••••••••••••••••••••••••••• „ · „ 225 4.2. Copolymers having a density of about 870 kglm3

„ „ „ „ „. „. „ „. „ „ „. 228 4.2.1. Micro chain structure ..... „ „ „ „ „ „. „ „ „ „ „ „ „ „ „ „ „. „ „ „. ... 228

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4.2.2. Crystalliz.ation and melting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 229 4.2.3. Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 233

4.3. Characteristic copolymers with densities below about 870 kg/m3 • • • • • •• 236

5. OVERVIEW . . . . . . . . . . . . . . .. . . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 239

ACKNOWLEDGMENTS . . . . . .. . .. ........... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 240

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 240

CHAPTER 7. RECENT ADV ANCES IN THERMAL ANALYSIS OF THERMOTROPIC MAIN-CHAIN LIQUID CRYSTALLINE POLYMERS (Christopher Y. Li)

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 245

2. LIQUID CRYSTALS AND LIQUID CRYSTALLINE POLYMERS . 247

3. THERMODYNAMIC TRANSITION BEHA VIORS . . ....... .. . . . . . . .... 253

4. ENANTIOTROPIC AND MONOTROPIC BEHA VIORS . .. . . . ..... .... 259

\

5. EFFECTS OF MESOGENIC GROUPS AND SPACERS ON 1HE LIQUID CRYSTALLINE ORDERS AND STABILITY . . . . . . . . . . . . . . .. 263

6. CONCLUDING REMARKS ............. „ .. „. „ ............ .. „......... .. 268

REFERENCES ........................................................................ 268

CHAPTER 8. POLYMER BLENDS AND CO POLYMERS (James Runt and Jiang Huang)

1. INTRODUCTION .......................... ................................ „. 273

2. BACKGROUND . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 273 2.1. Copolymers ........•......................................... „ ................ „ 273 2.2. Polymer blends ...... „ ................ „ .. „. „ ...... „ .... „................... 274

3. POLYMERBLENDS ......................................................... 274 3.1. Phase behavior- transitional analysis ............. „..... .. . .. . . . . . . . . . . .... 274

3.1.1. Background ..................... „ ..................... „ ......... „..... 274

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3.1.2. DSC . . . . . . .. . . . . . . . . . . . . . . . . . . . .. .. . . . . . .. . .. . .. . . . . .. .. . . .. ... . . ..... ... .. 276 3.1.3. Dynamic mechanical and dielectric measurements ................. 276 3.1.4. Crystalline blends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 279

3.2. Crystalline polymer blends and copolyrners ................................. 281 3.2.1. Co-crystallization ......................... „.............................. 281 3.2.2. Crystalline homopolymer-copolymer blends ........................ 281

3 .2.2.1. Poly(butylenes terephthalate )/poly( esrer-ether) copolymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 281

3.2.2.2. Polytetrafluoroethylene blends .............................. 286 3.2.3. Melting point depression and the interaction parameter............ 287

3 .2.3 .1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 287 3.2.3.2. Determination of equilibrium melting points . . .. . . . . ... . .. 288 3.2.3.3. Experimeiial. melting points - true melting points . . .. . . 290 3.2.3.4. Ramifications for estimation of x ........................... 291

ACKNOWLEOOMENTS . . ...... .... .. .. . .. . .. . .. . . .. . .. . .. . .. . .. . ... . . . . .. . . . . .... 291

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 292

CHAPTER 9. THERMOSETS (Arturo Hale)

1. INTRODUCTION ................................................... „...... .. 295

2. GENERAL CONCEPTS . . . . . . . . . . . .. . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 296

3. CHEMISTRY AND APPLICATIONS OF THERMOSETTING POLYMERS. ................................................................... 301

3.1. Phenolic resins. ..... ... .... .................... ........ ......................... 301 3.2. Melamines ...................................................................... „ 301 3.3. Unsaturated polyester and vinyl esters .............................. ..... .... 302 3.4. Epoxy resins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 3.5. Thennoset polyurethanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 3.6. Bismaleirnides ................................................................... 305 3.7. Cyanate ester resins ............................................................. 306 3.8. Polyirnides ........................................................................ 306 3.9. Benzoxazine resins .............................................................. 307 3.10 Silicon-based polymers ....................................................... 308

4. DETERMINATION OF EXTENT OF CURE ....... ...... ...... .. . ....... 308 4.1. Sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 309 4.2. DSC experimental parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

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4.2.1. Initial temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 4.2.2. Final temperature .. „ .•..... „ ............. „ .............•........ „. ..• 311 4.2.3. Hearing rate ......... „ ................................. „........... .. . . . 311

4.3. Determination of nonnalized extent ofreaction „ „ „. „ ... „ ... „ .... „ „. 311 4.4. Determination ofabsolute extent ofreaction ............. „.„ ...... „...... 312 4.5. Heats ofreaction ofselected groups ... „ ... „ .. „ ...... „ .. „.„............. 315

5. GLASS TRANSITION TEMPERATURE ...... „ .. „ .... „ .•......• „„„ 315 5.1. Generalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 315 5.2. Dependence of Tg on network and chemical structure . . . . . . . . . . . . . . . . . . . . . 318 5.3. Change in specific heat (ACp) .. „ .•.... „ .•... „ •..... „ ...•..•.... „.... .. . .• 323 5.4. Physical aging . . . . .......... ... . . .. . ... .. . . . . . . . ... .. . . .. . .. ... . . . . . . . ......... .. 325

6. REACTION KINETICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 6.1. General principles .................. „ .. „ „ ... „ .......................... „ „„ 330 6.2. Kinetic parameters determination ........................................... „ 334 6.3. Time-temperature superposition kinetics ............ „ .. „ .... „ .. „ ...... „ 336 6.4. Diffusion-controlled regime . . . . . . . ... . .. . . . . . .. . .. .. . . . . . . . . . . .. . . . . . . . . . . ... . 337

7. PHOTO-INITIATED POL YMERIZATION ...... ...................... ... 338 7.1. Free radical photo-polymerization .„„ .. „ ..... „„ ....•............. „... .•. 339 7.2. Cationic photo-polymerization ................................................ 342 7.3. Photo-calorimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . 342

8. MODULA TED TEMPERATURE DSC ....... „ ... „..... .. . . . . . . . . . . . ..... 348

9. CONCLUDIN"G REMARKS ....................... ..................... „.... 350

ACKNOWLEDGMENTS . . ................. .. . .. . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . .... 351

REFERENCES ................. „................................................. .... 351

CHAPTER 10. THERMAL ANALYSIS OF POL YMERFILMS (Lei Zhu)

1. IN"TRODUCTION ....... „ ..••....................•......•............ „ •.. „.. 355 1.1. Film preparation and production ............................................ „ 3 55 1.2. Multicomponent films ........................................................ „ 359

2. GENERAL EXPERIMENTAL CONSIDERA TIONS IN THERMAL ANALYSIS OF POLYMER FILMS .. „ .. . . .. . ... . . . . ... . . . . . . . . . ... . . . . . .. 360

2.1. Differential scanning calorimetry (DSC) ....... „ ....................•... „. 360

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2.2. Thermomechanical analysis (TMA) „„„„„„„„ ... „„„„ .• „„„ .. „... 360 2.3. Thermogravimetric analysis (TGA) „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ „.. 363 2.4. Dynamic mechanical analysis (DMA) „ „ „ „ „ „ „ „ „ „ „ „ „. „ „. „ „ „. 364 2.5. Dielectric analysis (DEA) . „„. „ „. „. „ „ „ „. „. „ „ „. „. „ „ ... „. „. „ „. 366 2.6. Thermally stimulated current (TSC) ... „.„.„ .. „„ ........ „.„.„ .. „.„.. 367 2. 7. Thermally stimulated creep ..................... „ ............ „ .... „ .... „.. 368

3. THERMAL ANALYSIS OF SPECIFIC POL YMERFILMS „„„„„. 369 3.1. Polyimides .. „ „ ........ „. „ ...... „ ....... „ •............. „ ................ „. 369 3.2. Polyolefins .. „ .... „ •... „ ... „. „ „ .•............. „ ......................... „. 381

3.2.1. Polyethylene (PE) ............. „ ................................... „... 381 3.2.2. Polypropylene (PP) . „ •. „ .. „ „ ... „ .... „ „. „ ... „. „ ....•........ „. 387

3.3. Poly(ethylene terephtbalate) (PET) „ ... „ ... „ ....•.•. „ .•. „ ••.. „ .... „ .. „ 392 3.4. Polyamides (nylons) .. „. „ ...• „ ... „ •. „ ...• „ .......•.......•.... „... .. . . . . . 399

3.4.1. Nylon 6 .. „ ..• „ .. „„„.„„ .• „„.„ .• „„.„ •.• „ •. „ •...•.•. „.„ .... „ 399 3.4.2. Nylon 66 ................................. „ ...•..• „ •....... „............ 403

4. CONCLUDING REMARKS .. „ .... „ .... „ ........•.......... „ .......... „ 404

REFERENCES .. „ .......... „.„ ....... „.„ ...... „ .. „ .......... „ ............. „. 404

CHAPTER 11. THERMAL ANALYSIS OF POL YMERFIBERS (Alexander J. Jing, Anqiu Zhang and Zongquan Wu)

1. INTR.ODUCTION ......... „ ... „ .• „ „ .....•.... „. „ ...•..•..•...•..•..•.. „ 409 1.1. Dimensions . „ ..•.... „ .... „ ... „ „. „ ..... „. „ „ ... „ ...• „ ...•.... „......... 409 1.2. Production of :fibers „ „ ....... „. „ „ .. „ „ .•. „ ..•. „ ....... „ „ •.. „ •... „ .. „ 410 1.3. Mecbanical properties „ „. „. „ „ „ „. „. „. „ .• „ „ „. „ „. „ „ .. „. „. „ „ „. 412

1.3.1. Terrninology „„ .. „. „„ „„„.„„„„„„„„„„„„.„„„„„. „„„ 412 1.3.2. Fiber stress-strain diagrams ............. „„ ....•..•. „ .. „ ...•..... „. 413 1.3.3. Elastic recovery „ ....•........... „ ................ „ ... „ ..•. „ .... „.„ 415

1.4. Heat-resistance and thermal stability „ „ „ „. „ „. „ „ „ „ „. „ „ „ „ „ „. „. 415 1.5. Water absorption, regain and moisture content „„„„„„.„„ .. „„„„„ 416

2. FIBER SlRUCTURE AND ITS DETERMINATION „„„ ..... „ .„.„„. 417 2.1. Two-phase model .„ .. „ ... „„„„„„„„ .• „„ .. „.„„ .„„ „„.„. „.„„.. 417 2.2. Intermediate state model „ „ ... „. „ .. „ „. „. „ „ .. „ „ •.. „ .. „ „ .. „ .• „ • . „ 417 2.3. Crystallinity ..... „„ ... „ .. „„ ... „.„„ ..... „.„ •.......... „ ....... „„.„„ 419

2.3.1. Wide angle X-ray diffraction (W AXD) .. „ ......•... „.............. 419 2.3.1.1. Modi:fied classic method „. „. „. „. „ „. „ „ „ ... „ „. „„„. 420 2.3.1.2. Mathematical simulation peak separation method „ .. „. 421

2.3.2. Small angle X-ray scattering (SAXS) ..... „ ........ „ ... „.„....... 421

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2.3.2.1. fuvariant power . „„ „ „ „. „ „ „ „ .• „ „ „. „„ „. „ „. „„. 421 2.3.2.2. Correlation functional length „ „ „ „ „ „ „ „ „ „ „ „ „ „ „ 422

2.4. Orientation and molecular chain conformation......................... .. .. 423 2.4.1. Birefringence .. „ ...•........•............... „ ...... „ ...... „.......... 423 2.4.2. Sound speed method for orientation measurement „ „ „ „ „ „. „ „ 424 2.4.3. Dichroism ..... „ ......•............. „ .•............ „ ................. „ 424 2.4.4. W AXD measurement of the degree of orientation in crystalline

region .. „.„ ................ „ .... „ ................... „ .......... „..... 425 2.4.5. Orientation of amorphous region „ „ „. „. „. „ „ „. „ „ „. „. „ „. „. 425

3. THERMAL ANALYSIS OF FIBER .. „ .•••.•.••.•.••.. „.................. 426 3.1. Differential scanning calorimetry (DSC) .„„.„.„.„„„„„ .. „„ .. „„.. 428

3.1.1. Fiber sample preparation „.„„„„„.„„„„„„„.„„„„.„„„.„ 428 3.1.2. Sample processing history .. „ ..................... „ .. „.............. 431 3.1.3. Heating rate effects on oriented fibers ................. „ ....... „ .. „ 431

3.2. Swelling differential scanning calorimetry (SDSC) .„„.„„„„„„ ... „. 431 3.3. Thenno-mechanical analysis (TMA) . „ „ „ „ „ „ „. „. „ „ „ „ „ „ „ „ „. „. 432 3.4. Dynamic mechanical analysis (DMA) „. „ „ „ „. „ „ .. „ „ „ „. „ „ „ „ „.. 434 3.5. Thennogravimetric analyzer (TGA) „ .„ „ „. „ „ .. „ „ „. „ „ „ .. „ „ „. „.. 435 3.6. Thennal wide angle X-ray diffraction (1WAXD) „„„„.„„„„„.„„„ 436 3. 7. Thennal small angle X-ray scattering (TSAXS) „ „ „. „ „. „ „ „ „ „. „ „. 437 3.8. Summary ofTA methods .„„„.„„„.„„„.„„„„„„„.„„ ..• „.„„.„ 438

4. CONVENTIONAL FIBERS AND THEIR MODIFICATIONS „„„„. 439 4.1. Conventional fibers .. „ .... „ .... „„ .... „ ...... „.„ ........•. „ .......•. „.„ 439

4.1.1. Nylon fibers .. „ ........................... „ .. „„ ... „„ ........... „.„ 439 4.1.1.1. Nylon 6 .. „ „ „ „ „ „. „ „. „. „. „ „ „ „. „ .. „ „ „ „ „ „ „ „ „ 441 4.1.1.2. Nylon 66 .. „.„ ... „„„ ....... „.„ .......... „ ....... „.„ .. „ 443

4.1.2. Polyolefin fibers .. „ ••••.•• „ ................ „ ............ „ „ ...... „.. 443 4.1.2.1. Polyethylene (PE) fibers „ „ „ „ „ „. „ „ „ „ „ „ „. „ „. „ „. 444 4.1.2.2. Polypropylene (J-PP) „.„.„„ .. „„.„„„„„„„.„„.„.„ 446

4.1.3. Polyacrylonitrile (PAN) .............. „.„ .. „ ............ „„ ..•. „.„ 448 4.1.4. Polyesters .. „ ................... „ ....... „. „ ....................... „.. 453

4.1.4.1. Poly(ethyleneterephthalate) (PE1) „„.„„„„ •. „„.„„ .. 453 4.1.4.2. Poly(butylenes terephthalate) (PBT) ...... „ ..•.•. „„.„„. 460

4.1.5. Poly(vinyl alcohol) (PVA) „„ .. „„„.„„„„„„„.„„.„„„„„. 462

5. HIGH PERFORMANCE FIBERS .. „ ...... „ .. „„ .............• „ .... „.. 463 5.1. Aromatic polyamide fibers ..... „ ...•.................. „ .....• „ ........... „ 464 5.2. Aromatic polyester fibers . „ .......... „ ........... „ ............... „ ..... „.. 469 5.3. Poly(phenylene sulfide) (PPS) „„„„„.„„„.„„„„.„„„ ••.• „„„„.„ 473 5.4. Poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI) „ •. „„ .. „„„„.. 474

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5.5. Arornatic polyimides .. .. . . . . . . . .. . . . . .. . . . . . . . . . . . .. . . ... . .. . . . . . . . . . . . . . .. . .... 476 5.6. Poly(ether ether ketone) (PEEK) .......... ............... ... ..... .. .......... 478 5. 7. Arornatic heterocyclic fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 79 5.8. Carbon fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480

6. CONCLlJDING REMARKS . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 482

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 482

CHAPTER 12. THERMAL PROPERTIES OF HIGH TEMPERA TURE POLYMER MATRIX FIBROUS COMPOSITES (Roger J. Morgan, E. Eugene Shin and Jason E. Lincoln)

1. INTRODUCTION ............................................................. 491

2. RESUL TS AND DISCUSSION . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495 2.1. Bismaleimide composite matrices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 495

2.1.1. Background and eure characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495 2.1.2. Cornposite microcracking formation and prevention . . . . . . . . . . . . . . . 499

2.2. Polyim.ide cornposites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 503 2.2.1. Background . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 503 2.2.2. Hydrotherrnal spike damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 504 2.2.3. Hydrolytic degradation „ „ „ „ ..... „. „ „ „ „ •...... „ .... „ „ ..... „. 508

3. CONCLlJDING REMARKS ................................................. 516

REFERENCES .. „ .........••.......... „ •........ „ ............ „ ........ „ .. „..... 517

CHAPTER 13. THERMAL ANALYSIS AND CALORIMETRY OF ELASTOMERS (Donald J. Burlett and Mark B. Altrnan)

1. INTRODUCTION .................... „ .......... „. „ .......... „ ........•• „. 519 1.1. Viscoelasticity .. „ .....•• „ ...... „ .. „ .... „ „ .. „ ......••.. „ ••.••... „ „ .. „ „ 520 1.2. Glass-to-rubber transition .......................... „. „ ............. „........ 521 1.3. Crystallinity . „ .......•......... „ .......................•........ ; ............. „ 5 21 1.4. Chernical composition ..... „ ...................... „ „ „ ..... „ ... „ ........ „. 522 1.5. Additives ..... „ .... „.... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 522 1.6. Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 523 1.7. Calorirnetry and thermal analysis techniques . .................... ...... .... 523

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2. CLASSES OF ELASTOMER .. . . . . . .. . ... .. . . . . ... .. . . . . . ... .......... .. ... . 526 2.1. Diene rubber {ho1I10polyrners) ................................................ 526 2.2. Diene rubbers (copolyrners) ................. :................................. 526 2.3. Halogenated rubbers ............................................................ 527 2.4. Vinyl rubber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528 2.5. Miscellaneous rubber ........................................................... 528

3. SINGLE ELASTOMERS . . .. . . . . . . . .. .. . . . . . . . . . . . . . . . .. . . ... . .. . .. . . . .. . . ... 529 3.1. Glass transition temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . 529 3.2. Crystalline melts . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 534 3.3. Stretching and deformation calorirnetry ..................................... 535 3.4. Thermal and oxidative stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 536

4. BLENDS . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538 4.1. Glass transition temperature ..... ........ .... ..................... .... ........ 539 4.2. ColilpOsition analysis ...................... ..................... ............ .... 541

5. ADDITIVES . . . . . ..... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . . . . . . . . .. . . .... 544 5.1. Fillers and reinforcing agents .......................... ................. ...... 545 5.2. Oils, plasticizers ....................... .. . ... ..................... .............. 553 5.3. Other additives and components ............................................. 555 5.4. ColilpOsitional analysis/formula reconstruction ....................... ..... 556

6. CURING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556 6.1. Peroxide eures.................................................................. 557 6.2. Sulfur-based ..................................................................... 559 6.3. Miscellaneous .,.................................................................. 564

7. ST ABILITY ........ ....................................... .......... ............ 566 7.1. Oxidative stability ............................................................... 567 7 .2. Thermal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 572 7.3. Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574

8. QUALl'fY CONfROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 576

9. FUTURE OPPORTUNITIES . ... . . . . .. . . . . .. . . . ... . . . . . .. .. . . . . . ... . . . . . . . .. 578 9.1. Instrumentation.................................................................. 578

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 580

CHAPTER 14. POLYMERDEGRADATION (Joseph H. Flynn)

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1. INTR.ODUCTION . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . .. 587

2. GENERAL PHYSICAL, STR.UCTURAL AND THERMODYNAMIC CONSIDERATIONS ......................................................... 589

2.1. Effect ofphysical state on degradation ...................................... 589 2.2. Energetics-bond energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 590 2.3. Thermodynamics-ceiling temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 590

3. GENERAL THERMAL DEGRADATION MECHANISMS . . . . . . . . .... 593 3.1. Types of degradation reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 593 3.2. Free radical chain reaction theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 594 3.3. Random scission . . .. . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. 601

3.3.1. General theory ........................................................... 601 3.3.1.1. Closed system .................................................. 602 3.3.1.2. ()pen systems ................................................. 603

4. GENERAL THERMO-OXIDATIVE MECHANISMS . . . .. . . . . ... .. ... . 608 4.1. Introduction and scope ......................................................... 608 4.2. Oxidation mechanisms ......................................................... 609

5. GENERAL HYDROLYSIS MECHANISMS . .... ......................... 613 5.1. Introduction .............. ................. ...................... .... ............. 613 5.2. Hydrolysis mechanisms .. ............... ....................................... 614

6. LIFETIME PREDICTION OF POLYMERS BY THERMAL ANALYSIS..................................................................... 614

7. SOME SPECIFIC EXAMPLES OF DEGRADATION .................. 616 7.1. Special cases forthe degradati.on ofvinyl type polymers .................. 616

7.1.1. Endinitiation, complete zip: [(poly(methylmethacrylate)] ........ 616 7 .1.2. Random initiation, complete zip: [poly( alpha-methylstyrene)] . . . 616 7.1.3. Poly(tetrafluoroethylene) .. .. ....... ........... ......... .. . ...... .... ... 617 7.1.4. Polystyrene ............................................................... 617 7.1.5. Other special cases .. .. ..... ......................... ...... ......... ..... 619

7 .2. Degradation of some other vinyl-type polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619 7.2.1. Poly(vinyl chloride) (PVC)............................................ 619 7.2.2. Poly(methylacrylic acid) (PMAA) .................................... 622 7.2.3. Polyvinyl acetate (PV A) . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 622 7.2.4. Polyvinyl (isopropenylacetate) (PVIPA) ............................. 622 7.2.5. Polyvinyl alcohol (PV AL) . . .. . . . . . . . . . . . . . . ... . . .. . . . . . . . . . . . . . . . . . . . . 623

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7 .3. Degradation of some heterochain polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623 7.3.1. Polyacetal and related polyethers ................................... 623 7.3.2. Nylon 6 ................................................................. 624 7.3.3. Poly(ethylene adipate) .......... . ..................................... 624 7.3.4. Polyurethanes......................................................... 625 7.3.5. Polyethylene terephthalate (PEn . . . . . . . . .. ... . . . . . . . .. . . . . . . . . . . ... 625 7.3.6. Polysiloxanes .......................................................... 626 7.3.7. Cellulose . .......... ........ .... ... .... ......................... ........ 626

7.4. Pryolytic reactions and aromatic and temperature-resistant thermo-setting polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 627 7.4.1. Poly(phenylenes) ........................................................ 627 7.4.2. Phenolformaldehyde resin ............................................. 628 7.4.3. Epoxyresins ........... . ............................................... 629 7.4.4. Polycarbonates . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . ... . . 629 7.4.5. Poly(pyromellitimide) H film......................................... 629 7.4.6. Polyacrylonitrile (PAN)................................................ 630

8. COPOL YMERS, BLENDS, MIXTURES . . .. .. . . ... . . . ... . . .. . . . . . . . . . . . .. 631 8.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631 8.2. Simple degradation theory and early investigations . . . . . . . . . . . . . . . . . . . . .... 632 8.3. More recent investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 635

8.3.1. Thermal degradation of some altemating copolymers . . . . . . . . . . . . . 63 5 8.3.2. Thermal degradation of block copolymers . .. .. . . . . . . . . ... . . . . . . .... 637 8.3.3. Thermal degradation of some random copolymers . . .. . . . . . . . ... . .. 637 8.3.4. Thermal degradation of some blends and mixtures . . . . . . . . . . . ... . .. 639

9. CONCLUDING REMARKS ................................................. 641

10. BIBLIOGRAPHY ............................................................ 641 11. REFERENCES ................................................................ 645

CHAPTER 15. THERMALLY STIMUIA TED CURRENTS: RECENT DEVELOPMENTS IN CHARACTERIZA TION AND ANALYSIS OF POLYMERS (Bryan B. Sauer)

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 653

2. EXPERIMENTAL SECTION ...... .. . .............. ................. ........ 657 2.1. TSC instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 657 2.2. Sample preparation and geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 658 2.3. Polarization/Depolariz.ation sequences . ... ...... ...... ...... .......... .. . .... 659

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3. ANALYSIS OF TSC-TS DATA „„„„„„„„„ .. „„„„„„„ .. „„„„. 660 3.1. Bucci-Fieschi-Guidi and related analysis methods . . . . . . . . . . . . . . . . . . . . . . . . 660 3.2. TSC-TS curve fitting methods ........ „ .. „ „ .... „ ....................... „. 662 3.3. Conipensation „„.„„„„„„.„„„„„„ .. „„„.„„ .. „„ .. „ ... „.„„ .. „ 664

4. INTERPRETATION OF GWBAL TSC RESULTS „.„„„.„„„.„„ 667 4.1. Comparison of global TSC with a.c. dielectric and other techniques .. „ 667 4.2. Global TSC studies of glass transitions and T> Tg transitions,

comparisons with other techniques .. „ ......... „ ................ „ ..... „.. 668 4.3. Interpretation ofthe T> Tg or p transition at higher temperatures ....... 673

5. INTERPRETATION OF TSC-THERMAL SAMPLING (fSC-TS) RESlJLTS „ .•• „ ••..•....• „ •...•••..••...•••.• „ .. „ •....• „ •..•...••••..••• „. 674

5 .1. Comparison of fitting routines for TSC-TS spectra applied to experimental data .. „ „. „ „ „ „. „ „. „ „ „ „ „. „ „. „ „ .. „ „ „. „ .• „. „ „„ 675

5.2. Comparison of TSC-TS apparent activation energies with standard relaxation methods .......................... „ .... „ ....... „ ............ „ .. „ 681

5.3. The zero entropy prediction and a description of methods for distinguishing cooperative and non-cooperative relaxations . . . . . . . . . . . . . 686

5.4. Explanation of high sensitivity ofTSC-TS for cooperative motions .. „. 688 5.5. Selections from TSC-TS literature and comparison with the zero

entropy prediction .. „ ............. „ ••..••••..••• „ ••.••••.•••••••••. „ „ ••• „. 691 5 .6. Comparison with new analysis of derivatives of a.c. dielectric data to

obtain activated parameters ...................... „ ........ „ .......... „ „ 694

6. TSC APPLICA TIONS ................. „ .......... „ ....... „ ...... „ ..... „.. 697 6.1. Examples ofTSC and TSC-TS studies ofamorphous polymers .. „..... 697 6.2. Amorphous and semi-crystalline liquid crystalline polymers „ „. „ „ „ „ 698

6.2.1. Side-chain LCPs ........ „ ............. „ ................ „.............. 698 6.2.2. Copolyester main-chain LCPs with broad glass transitions ....... 701

6.3. High crystallinity flexible polymers and fluoropolymers .............. „„ 703

7. CONCLUDING REMARKS . „ ............... „ ............•.............. „ 706

ACKNOWLEDGMENTS .. „ .... „ ............................ „ ................ „ 708

REFERENCES ................. „ .......... „ ...................... „ ............. „. 708

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CHAPTER 16. TEMPERATURE MODULA TED DIFFERENTIAL SCANNING CALORIMETRY (TMDSC) -BASICS AND APPLICATIONS TO POLYMERS (C. Schick)

1. INTRODUCTION ............................................................. 713

2. DIFFERENTIAL SCANNING CALORIMETRY (DSC)- BASIC CONSIDERATIONS .......................................................... 717

2.1. Heat-flux DSC ................................................................... 717 2.2. Tian-Calvet type DSC ............... „ ..... „ ......•. „. .. ... ... ...... .... ..... 719 2.3. Power compensation DSC ........... .. ................ .... „ •........... „ .. „ 720 2.4. Combination ofheat-flow DSC and power compensation ................ 721

3. TEMPERATURE MODULATED DIFFERENTIAL SCANNING CALORIMETRY (TMDSC) . ... .. . .. . . . ... .. . . . .. ... . . . . .. . . . . . . . . . . . . . .. . .. 722

3.1. Complex heat capacity and reversing and non-reversing heat capacity . 723 3.1.1. Determination of reversing and non-reversing heat capacity ... 724

3.1.1.1. Temperature modulated DSC (TMDSC) „.„ ...•. „.... 724 3.1.l .2. StepScan ™ DSC (SSDSC) ....... .......... „ .......... „.. 727

3.1.2. Determination of oomplex heat capacity ............ „ ......... „.. 731 3.2. Data treatrnent algoritluns ... „ ......•..... „ ..•.. „„ •......•............. „... 732 3.3. Frequency dependentheat capacity ........................ „„ .......... „.. 737

3 .3.1. Periodic perturbations - frequency domain .. „ ............ „ ... „. .. 738 3.3.1.1. Single frequency measurements ............ „„ ..... „...... 738 3.3.1.2. Multi frequency measurements ........... „.„ •. „.......... 738

3.3.2. Non-periodic perturbations-step response in time domain ...... 741 3.4. Calibration . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 744

3.4.1. Heat capacity calibration ............................................. „ 744 3.4.2. Temperature calibration .. „... .. . . . . . . . . . . . . . . . . . . ... . .. . .. .. . . . . . . . . . . 748 3.4.3. Heat capacity calibration examples ................ „ .. •. . • . . . .. .... .. 749

3.4.3.1. Results from "fust-order" calibration „„ .. „ ..... „ •. „.... 750 3.4.3.2. Results from "second-order" calibration ... „.............. 752 3.4.3.3. ''Third-order" calibration .... „ .... „ ...•......... „ „ .. „ .. „ 755 3.4.3.4. Remark concerning small samples ........ „ ..... „... .... .. 758

3.4.4. Conclusions regarding calibration ......... „ .................. „..... 758 3.5. Thennal conductivity „ „ „ „ „ ... „ .... „ „ ... „ „ .. „ .. „ „„ „ .. „. „„ „ .... 760

3.5.1. Data treatrnent „ ... „„„„.„„.„.„„.„ .. „„„.„„.„.„„„ .. „„. 761 3.5.1.1. Tue idea „„„„ ... „.„„ ...... „ .. „„ .. „ ... „„ .. „„.„„„ 761 3.5.1.2. Tue algorithrn .„ ... „„ .. „„„„„.„„ ... „ ..... „ .. „„ .. „. 761

3.5.2. Experimental results .. ................................................ „ 765 3.5.3. Discussion ofthermal conductivity determination .„ .. „ .. „„.... 767

XXV

3.5.4. Conclusion regarding thermal conductivity . . . . . . . . . . . . . . . . . . . . . . . . . 768

4. APPLICA TIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... 768 4.1. Precise heat capacity . . . . . . .. . . . .. . . . . . . . . . . . . . . .. .. . . . . . . . . . . .. . .. . . . . . . . .. . .... 768 4.2. Glass transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 770

4.2.1. Vitrification and dynamic glass transition . . . . . . . . . . . . . . . . . . . . . . . . . . . 770 4.2.2. Non-reversing heat capacity at glass transition . . . . . . . . . . . . . . . . . . . . . 774

42.2.1. General criticism . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 774 4.2.2.2. Enthalpy retardation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775

4.2.3. Modeling the results from TMDSC at glass transition ............. 777 4.2.4. Glass transitions superimposed by latent heats . . . . . . . . . . . . . . . . . .. . . . 778

42.4.1. Basic considerations . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 778 4.2.4.2. Glass transition superimposed by melting . . . . . . . . . . . . . . .... 780 4.2.4.3. Glass transition superimposed by crystallization ....... .. 781 4.2.4.4. Glass transition superimposed by chemical reactions . . .. 784 4.2.4.5. Glass transition superimposed by evaporation ............ 784

4.2.5. Conclusions regarding glass transition .. ......... ............ ........ 785 4.3. Phase transitions ...... ........... .. ....... ...................................... 786

4.3 .1. First-order phase transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . 787 4.3 .1.1. Calibration related problerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 787 4.3.1.2. Reorganization - Tue influence of the temperature time

profile . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789 4.3.1.3. Crystallization and melting kinetics ........................ 792

4.4. Reversing melting and crystallization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793 4.5. Other processes .................................................................. 800

5. CONCLUDINGREMARKS ................................................. 801

ACKNOWLEDGMENTS . .. . . . . ... . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . .. . . .. . . . . . . .. . .. 802

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 802

INDEX................................................................................. 811