Characterization & Identification of Polymers Presentation

7/31/2019 Characterization & Identification of Polymers Presentation

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1To ic IV.1 & 2 Courtesy of University of Leoben, Austria

Topic IV:Structural Characterization and Identification of Polymers

IV.1. Thermoanalytic methods- Differential thermal analysis (DTA) & differential scanning calorimetry (DSC)- Thermogravimetric analysis (TGA)- Thermomechanical analysis (TMA)

IV.2. Spectroscopic methods- IR Spectroscopy

IV.3. Microscopic methods- Optical/light Microscopy- Scanning Electron Microscopy

IV.4. Diffraction methods- X-Ray Diffraction


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Differential Thermal Analysis (DTA) & Differential Scanning Calorimetry (DSC)Methods based on measurement of heat consumed (endo) up or released (exo)to the surrounding per unit time during isothermal (hold), heating or cooling

processes.

Thermogravimetric Analysis (TGA)Measurement of changes of polymer weight as a function of temperature.

Thermomechanical Analysis (TMA)Measurement of dimensional changes during heating or cooling

Thermoanalytic Methods


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Thermoanalytic Methods - DTA

Differential Thermal Analysis (DTA)

Sample (~10mg) pan and reference pan are placed in an oven. The oven is usually heated or cooled at a rate ranging from 0.1 to 100 K/min.

Temperature difference (T) between sample and reference pan measured and recorded.


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Thermoanalytic Methods DTA/DSC

380 400 420 440 460-15

-10

-5

0

5

heatflux[W

/g]

temperature [C]

Zinc

endo

exo

TM

= 419.6 C

130 140 150 160 170 180-20

-15

-10

-5

0

5

H100%

= 28.45 J/g

TM

= 156.6 C

heatflux[W

/g]

temperature [C]

Indium

endo

ex

o

Calibration of Temperature and Heat Flux

ZincIndium


6/426To ic IV.1 & 2 Courtesy of University of Leoben, Austria


Application of DTA/DSC

Thermal transitions (e.g., glass transition, phase transitions) Melting behavior, -temperature, -enthalpy; specific heat

Crystallization behavior; recrystallization Degree of crystallinity

Annealing and curing processes; thermal stability

Desorption, evaporation, decomposition Efficiency of additives

Chemical reaction enthalpy, reaction temperature, reaction kinetics



50 100 150 200

temperature [C]

1

0

PC film

50m

heatflux[W/g]

ex

o

endo

TG = 150C


Amorphous Polymers Glass TransitionPolycarbonate (PC)

glass transition



50 100 150

-11

-10

-9

-8

-7

-6

heatflux

[W/g]

temperature [C]

ABS/PC blend

e

xo

endo


Amorphous Polymers Glass TransitionABS/PC blend

glass transition

ABSPC




Amorphous Polymers Glass Transition




Amorphous thermoplastics Glass transition temperature [C]

Polyvinylchloride (PVC) 80

Polystyrene (PS) 95

Polymethylmethacrylate (PMMA) 105

Polycarbonate (PC) 150

Polysulfone (PSU) 190

Polyethersulfone (PES) 230

Polyetherimide (PEI) 220

Athas Databank:http:web.utk.edu/~athas/databank/

Engineering and high temperature-resistant, amorphous polymers (PC, PSU, PES, PEI, etc.)contain aromatic rings, giving the macromolecule main chain a 2-dimensional (ladder-like) structure.




Semicrystalline Polymers Melting BehaviourPE-HD

60 80 100 120 140 160

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

TM

= 135C

heatflux

[W/g]

temperature [C]

PE-HDexo

endo




Semicrystalline Polymers Melting Behaviour

PE-HD and PE-LD

60 80 100 120 140 160

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

X

TM

= 115C

TM

= 135C

heatflux

[W/g]

temperature [C]

PE-HD

PE-LD

e

xo

endo

X





PE-LD / PP blend

40 60 80 100 120 140 160 180 200-1.1

-1.0

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

heatflux

[W/g]

temperature [C]

PE-LD/PP Blend

exo

endo

XTM = 165C

TM

= 115C

X





w/o enthalpy relaxation

with enthalpy relaxation

Blend



60 80 100 120 140 160

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

TM

= 135C

heatflux[W/g]

temperature [C]

PE-HDex

o

endo

X

60 80 100 120 140 160

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

heatflux[W/g]

temperature [C]

PE-HDex

o

endo

Melting Enthalpy (H) = 188 J/g

Thermoanalytic methods DTA/DSC

Semicrystalline Polymers Degree of Crystallinity

PE-HD


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Semicrystalline Polymers Degree of Crystallinity

= H /H100%cr

... Degree of crystallinity

H ... Measured melting enthalpy

H100%cr ... Melting enthalpy for 100% crystalline material

Example PE-HD:

= 188/294 = 64%


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Semicrystalline polymer Melting temperature[C]

Melting enthalpy for100% crystallinity [J/g]

Polyethylene (PE) 80 150

165

180

260

270

350

175

325

294

Polypropylene (PP) 207

Polyoxymethylene (POM) 326

Polyamide 6,6 (PA66) 270

Polyethyleneterephthalate (PET) 153

Polyether ether ketone (PEEK) 130

Poly(vinylidene fluoride) (PVDF) 105

Polytetrafluoroethylene (PTFE) 41

Athas Data bank:

http:web.utk.edu/~athas/databank/http://athas.prz.rzeszow.pl/databank/welcome-db.html


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Semicrystalline Polymers Melting vs. Crystallization

PTFE

200 220 240 260 280 300 320 340 360-6

-4

-2

0

2

4

6 TCr

= 310 C

heatflux

[W/g]

temperature [C]

PTFEexo

endo

cooling, -10 K/min

heating, 10 K/min

TM

= 327C


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Semicrystalline Polymers Postcrystallization

PET

50 100 150 200 250 300-20

-15

-10

-5

0

5

TM

= 250 C

TPostCr

= 150 C

heatflux

[W/g]

temperature [C]

quenched PET

endo

exo

TG

= 75 C


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Polyolefines exhibit autooxidation. Oxidation temperature (TOx) is affected by stabilization and ageing.

weathering

50 100 150 200 250

2

0

unaged

weathered

PP film

heatflux[W/g]

temperature [C]

exo

endo

TOx

= 220 C

Degradation / Oxidation of Polymers - PP

Th l ti M th d DTA/DSC


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Epoxy Resin - Relationship Between Degree of Cure

& Glass Transition Temperature

70 75 80 85 90 95 10060

80

100

120

140

160

180

200

220

epoxy resin

glasstrans

itiontempe

ratureT

gDS

C,

C

degree of cureDSC

, %

Th l ti M th d TGA


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Thermoanalytic Methods - TGA

Thermogravimetrical Analysis (TGA)

Sample (~10 mg) and crucible, connected to a microbalance, are placed in an oven. The oven is usually heated or cooled at a rate ranging between 0.1 and 100 K/min.

The change of weight (m) is measured as a function of temperature.

Th l ti M th d TGA


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Thermoanalytic Methods - TGA

Thermogravimetrical analysis (TGA)

0 100 200 300 400 50085

90

95

100

< 10 wt% phenolresin coating

temperature [C]

Phenol resin coated mineral wool

Relativemass[%]

< 2 wt% water content

Determination of volatile components (e.g., water, solvents, etc.) Determination of mineral filler or reinforcement content of plastics.

Topic IV:


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pStructural Characterization and Identification of Polymers

IV.1. Thermoanalytic methods- Differential thermal analysis (DTA) & differential scanning calorimetry (DSC)

- Thermogravimetric analysis (TGA)- Thermomechanical analysis (TMA)

IV.2. Spectroscopic methods

- IR Spectroscopy

IV.3. Microscopic methods- Optical/light Microscopy- Scanning Electron Microscopy

- Atomic force Microscopy

IV.4. Diffraction methods- X-Ray Diffraction

Spectroscopy


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Spectroscopy

Spectroscopic methods play an important role in structural analysis of polymers.

Spectroscopic phenomena are associated with the absorption or emission ofelectromagnetic radiation.

: wavelength

IR Spectroscopy


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IR - Spectroscopy

Infrared spectroscopy (IR)

For the analysis of plastics, infrared radiation with wavelength between2.5m and 25m is used.

For experimental reasons usually the wavenumber () is used instead of thewavelength ().

= 1/*10000 : wavenumber in cm-1 and

: wavelength in m

IR Spectroscopy


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IR - Spectroscopy

Infrared spectroscopy (IR)

The IR radiation causes rotations and vibrations of molecules and atomic groups. The oscillations are described by spring-mass-systems:

m2

m1

km1 : mass of group 1 (e.g., H, O, N, S, Cl, F, CH3 )

m2 : mass of group 2 (e.g., C, macromolecule)K : spring constant (e.g., C-H, C-O, C=O, C-N ...)

Absorption occurs when the exciting frequency is equal to the resonancefrequency of the system.

Due to the many different groups in polymers many different oscillations withspecific absorption peaks occur.

IR - Spectroscopy


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IR - Spectroscopy

Vibrations of CH2groups

C

HH

symmetric CHstretching vibration Antisymmetric CHstretching vibration H-C-H deformation(bending)

Rotation of CH2 group

(twisting)

Out-of plane pendulum vibration ofthe CH2 group (wagging)

In-plane pendulum vibrationof the CH2 group (rocking)

IR-Spectroscopy

IR - Spectroscopy
http://en.wikipedia.org/wiki/Infrared_spectroscopyhttp://en.wikipedia.org/wiki/Infrared_spectroscopy


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IR - Spectroscopy

Experimental IR-Spectrophotometer

Heatradiationsource

Interfero-meter

Detector,

Computer

Samplecompartment

IR-spectroscopy - PE


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IR spectroscopy PE

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

transmission[%]

w a v e n u m b e r [ c m-1

]

C H 2

Vibration Range

a CH2,s CH2 3000-2840

CH2 1471

CH2 717

* C C

H

H

*

H

H

n


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IR-spectroscopy - PS


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IR spectroscopy PS

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

transmissio

n[%]

w a v e n u m b e r [ c m - 1 ]

p h e n y l e n e

Vibration Range

=CH 3150-3000

a CH2,s CH2 3000-2840

Vibration Range

Ph 1600-1375

=CH 1067

=CH 1027

Vibration Range

=CH 906

=CH 754

Ph 695

* C

H

H

C *

H

n

IR-spectroscopy plasticized PVC


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IR spectroscopy plasticized PVC

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0

7 0

7 5

8 0

8 5

9 0

9 5

1 0 0

transmis

sion[%]

w a v e n u m b e r [ c m - 1 ]

O H

Vibration Range

OH (plasticiser) 3331

a CH2, s CH2, CH 3000-2840

C(=O)C (plasticiser) 1720 CH2 1426

Vibration Range

CH, C-O-C (plast.) 1264

C-O (plast.) 1122, 1072

C-C 966 CH 742

* CH2 CH

Cl

*n

IR-spectroscopy PA12


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IR spectroscopy PA12

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 04 0

5 0

6 0

7 0

8 0

9 0

1 0 0

transmission[%]

w a v e n u m b e r [ c m - 1 ]

N H

C = O

N H , N C

C H 2

Vibration Range

NH 3287

a CH2 2918

s CH2 2850 C=O 1634

Vibration Range

NH, CN 1553, 1269

CH2 1465

CH2, CH2 1200 CH2 720

* C CH2O

NH *n

z

IR-spectroscopy - PET


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spect oscopy

4 0 0 0 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 00

2 0

4 0

6 0

8 0

1 0 0

transmiss

ion[%]

w a v e n u m b e r [ c m - 1 ]

O = Cp h e n y l e n e

Vibration Range

a CH2, s CH2 3000-2840

C=O 1713

Ph 1600-1325 C(=O)O, =CH 1242

Vibration Range

O-C, =CH 1095

=CH 1017

=CH 956, 873 Ph 725

* C

O

C O

O

CH2

CH2

O *n

IR-spectroscopy PTFE and ETFE


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p py

4 0 0 0 3 5 0 0 3 0 0 0 2 0 0 0 1 5 0 0 1 0 0 0

2 0

4 0

6 0

8 0

1 0 0

w a v e n u m b e r [ c m - 1 ]

transmission[%]

E T F E C - F C - C - F

2 0

4 0

6 0

8 0

1 0 0

transmission

[%]

P T F E

C F 2

PTFE: Vibration Range

a CF2 1200

s CF2 1145

ETFE: Vibration Range

a CH2, s CH2 3000-2840

CH 971

s CH2 1453, 1248, 1162

C-F 1323, 1038

CH2, C-C-F 666

* C C *

F

F

F

F

n

* C C C C

H

H H

H

*

F F

F F

n

IR-spectroscopy PES and PSU


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p py

4 0 0 0 3 5 0 0 3 0 0 0 2 0 0 0 1 5 0 0 1 0 0 0

8 0

8 5

9 0

9 5

1 0 0

transmission[%]

w a v e n u m b e r [ c m - 1 ]

P S U

6 0

7 0

8 0

9 0

1 0 0

transmission[%]

P E S

p h e n y l e n e

S O 2

Vibration Range

=CH 3086

a Me 1486

a Me, s Me 3000-2840

Ph 1600-1320

a SO2, =CH 1293, 1147

Vibration Range

a C-O-C 1233

=CH 833

=CH 1103

=CH, Me 1012

Ph 687

* O S *

O

O

n

* O C

CH3

CH3

O S

O

O

*n

IR-spectroscopy PEI and PI


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p py

4 0 0 0 3 5 0 0 3 0 0 0 2 0 0 0 1 5 0 0 1 0 0 08 89 0

9 2

9 4

9 6

9 8

1 0 0

w a v e n u m b e r [ c m - 1 ]

transm

ission[%]

P E IN C 2

9 2

9 4

9 6

9 8

1 0 0

transmission[%]

P I

i m i d e

Vibration Range

=CH 3150-3000

Ph 1600-1300

a Me & s Me (PEI) 3000-2840

a C=O, s C=O 1775, 1725

imide (PI) 1375

Vibration Range

imide, s Me (PEI) 1355

s C-O-C 1167, 1114, 1082

=CH (PI) 881, 821

C=O (PEI) 848

imide, aC-O-C (PI) 1243

s NC2 (PEI) 1236

C

C

O

N

C

C

O

N On

O O

C

C

O

O

N* O C

CH3

CH3

O

C

C

O

O

N

*n

IR-spectroscopy - EVA


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4 0 0 0 3 5 0 0 3 0 0 0 2 0 0 0 1 5 0 0 1 0 0 00

2 0

4 0

6 0

8 0

1 0 0

transmission[%]

w a v e n u m b e r [ c m - 1 ]

5 %

0

2 0

4 0

6 0

8 0

1 0 0

tr

ansmission[%]

2 4 %

Vibration Range

a CH2, s CH2 3000-2840

a CH3,s CH3 3000-2840

C=O 1740

CH2, a Me 1469

Vibration Range

s Me 1371

C(=O)O 1241

O-C, Me 1020

CH2 720

* CH2 CH *

O C CH3

O

n

IR-spectroscopy - EVA


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A = ln (0/)

Determination of Vinylacetate (VA) content

* C C

H

H

*

H

H

n

* CH2 CH *

O C CH3

O

n

Ethylene

A...Absorption

...transmission

Vinylacetate band:A(1240cm-1)...(C=O)O group

Ethylene band:

A(1472cm

-1

)...CH2, CH3 groups

5 10 15 20 25

Vinylacetate

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

A(1240cm-1

)/

A(1472cm

-1

)

VA [%]

y = 0,1427x + 0,038

R2

= 0,9646

IR-spectroscopy (ATR) - PE


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= 100% * [1-(Ia

/Ib

)/1.233]/(1+Ia

/Ib

)

Determination of PE-crystallinity

760 740 720 700 680

crystallinity value

Ia: Intensity peak area of the 730 cm-1 band

Ib: Intensity peak area of the 720 cm-1 band

1.233: area-ratio of pure crystalline polyethylene

720

Ib

- amorphous

absorptio

n[-]

wave number [cm-1]

730

Ia

- crystalline

IR-spectroscopy (ATR) - PE


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3 0 0 0 2 9 0 0 2 8 0 01 5 0 0 1 4 0 0 1 3 0 0 1 2 0 0 1 1 0 0 1 0 0 0 9 0 0 8 0 0 7 0 0

absor

ption[-]

w a v e n u m b e r [ c m - 1 ]

4 7 %

absorption[-] 8 1 %

* C C

H

H

*

H

H

n

Vibration Range

a CH2,s CH2 3000-2840

CH2 1500-1460

CH3 730-720

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Characterization & Identification of Polymers Presentation