SPE Thermal Analysis 2018 Solid · 2018. 12. 6. · Polypropylene Random...

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Thermal Analysis in Failure and Compositional Analysis

Jeffrey A. JansenDecember 5, 2018

Thermal Analysis Jeffrey A. Jansen The Madison Group

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Goals

• Become familiar with how thermal analysis can be used to identify and characterize polymeric be used to identify and characterize polymeric materials.

• Gain insight into how composition and structure can be evaluated analytically.

• Understand which thermal analysis technique to use to get the desired information.


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Agenda

• Introduction• Differential Scanning Calorimetry• Differential Scanning Calorimetry• Thermogravimetric Analysis• Thermomechanical Analysis• Dynamic Mechanical Analysis


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Thermal Analysis

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Jeffrey A. Jansen The Madison Group

12/6/2018

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DIFFERENTIAL SCANNING CALORIMETRY DIFFERENTIAL SCANNING CALORIMETRY (DSC)


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DSC measures the temperatures and heat flows associated with transitions in

DSC

heat flows associated with transitions in materials as a function of time and temperature in a controlled atmosphere. The difference in the


amount of heat required to increase the temperature of a sample and reference is measured.

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DSC measurements provide quantitative and qualitative information

DSC

quantitative and qualitative information about physical and chemical changes that involve endothermic or exothermicprocesses, or changes in heat capacity.


Endothermic: heat flows into the sampleExothermic: heat flows out of the sample

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DSC


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PET

DSC


ASM Handbook Vol 11 “Characterization of Plastics in Failure Analysis”Jeffrey A. Jansen,

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DSC Samples DSC ExperimentsV i f l

DSC

• Intractable Solid• Powder• Liquid• Typically 5-25 mg

• Variety of sample pans depending on experiment – Typically Al

• Heating capability to 725°C

• Variable heating rate –Variable heating rate typically 10 °C/min.

• Variety of purge gases –typically inert (N2)


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DSC Applications• Material identification

DSC

– Polymer identification– Polymer type differentiation– Copolymer vs. homopolymer

• Material condition– Degradation– Purity / Contamination– Oxidative stability

• Material properties – heat historyCrystallinity


– Crystallinity– Thermal history– Specific Heat capacity– Heat of reaction / reaction kinetics– Degree of cure

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Semi-crystalline vs. Amorphous 0.11 Polyethylene––––––– Poly(m ethyl m ethacrylate)–––––––

DSC – Material ID

-0.1

0.0

Hea

t Flo

w (W

/g)

-2

-1

0

Hea

t Flo

w (W

/g)

Semi-crystalline

Amorphous

-0.3

-0.2

-4

-3

0 50 100 150 200 250Tem perature (°C )Exo Up Universal V4.7A TA Instrum ents

Amorphous


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Glass transitions are much weaker than melting transitions

1P o lye thylene–––––––

DSC – Material ID

-2

-1

0

Hea

t Flo

w (W

/g)

P o lye thylene––––––– P o ly(m ethyl m e thacryla te )–––––––

-4

-3

25 75 125 175 225Tem pera ture (°C )E xo U p U n iversa l V 4 .7 A T A In stru m ents


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DSC – Material IDMelting point can be used to identify plastics

0

-2

-1

Hea

t Flo

w (W

/g)

P o lye thylene––––––– P o lypropylene––––––– P o ly(butylene te rephtha la te )––––––– N ylon 6 /6–––––––

P o ly(phenylene su lfide )

-4

-3

0 100 200 300 400Tem pera ture (°C )

P o ly(phenylene su lfide )––––––– P o lye the re the rke tone––––––– P o lye the rke tonee the rke toneke tone–––––––

E xo U p U n iversa l V 4 .7 A T A In s tru m en ts


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DSC – Material ID

Similar FTIR spectra

2 1 1 .7 1 ° C5 0 .6 0 J /g

2 5 0 .8 5 ° C5 9 .9 2 J /g

0 4

- 0 .2

0 .0

)

N y lo n 6– – – – – – – N y lo n 6 /6– – – – – – –

2 2 1 .3 1 ° C2 6 0 .9 0 ° C

- 1 .2

- 1 .0

- 0 .8

- 0 .6

- 0 .4

Hea

t Flo

w (W

/g)

2 5 7 5 1 2 5 1 7 5 2 2 5 2 7 5 3 2 5T e m p e r a tu r e ( ° C )E x o U p U n iv e r s a l V 4 . 7 A T A I n s t r u m e n t s

Different melting points


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DSC – Material ID

PEEK

PEKEKK


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0.0

0.0

0.5

DSC – Material ID

167.83°C

164.16°C

119.42°C -0.2

-0.1

Hea

t Flo

w (W

/g)

-2 0

-1.5

-1.0

-0.5

Hea

t Flo

w (W

/g)

148.49°C-0.4

-0.3

-3.0

-2.5

-2.0

0 50 100 150 200Tem perature (°C )

Polypropylene H om opolym er––––––– Polypropylene B lock C opolym er––––––– Polypropylene R andom C opolym er–––––––

Exo U p U niversa l V4.7A TA Instrum ents


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DSC – Material IDGlass transition temperature can be used to identify plastics


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DSC can provide information about polymer blends-0 .2

P C +A B S B lend––––––– P C +A B S A lloy–––––––

DSC – Material ID

108 .05°C (I)

109 .98°C (I)-0 .03551W /g

-0 .4

-0 .3

Hea

t Flo

w (W

/g)

Single Tg – Alloy with miscible configuration

Double Tg – Blend with ( )

-0 .02737W /g

134 .95°C (I)-0 .02545W /g

-0 .6

-0 .5

0 50 100 150 200Tem pera ture (°C )E xo U p U n iversa l V 4 .7A T A Ins trum en ts

two phases


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• Housing for Electrical Appliance

Appliance Housing

DSC

pp• Failures Occurred During

Assembly - Insertion of Screws Into Bosses

• Failures Limited to a Production Lot

• Injection Molded• Acrylonitrile:butadiene:


• Acrylonitrile:butadiene: styrene (ABS) Resin -Grade Unknown

• Regrind Used in Production

Source: “Testing Beats Talking”, Appliance Manufacturer, Business News Publishing Company, J.A.. Jansen, March 2001, pg. 21-24.

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• Cracking within screw bosses

Appliance Housing

DSC

bosses

• Brittle fracture appearance

• No significant ductility -stress whitening and permanent deformation absent


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• Reference good parts produced results for

Appliance Housing

DSC

produced results for ABS

• Failed parts produced results with ABS bands and additional absorbances


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Appliance Housing• Reference good parts

produced results for

DSC

produced results for ABS

• Failed parts produced results with ABS bands and additional absorbances

• Contamination with


thermoplastic ester

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• Melting point indicative of

Appliance Housing

DSC

contamination - PBT Resin


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• Molded plastic couplings exhibited abnormally brittle

Plastic Couplings

DSC

yproperties.

• Specified to be molded from a custom-compounded glass-filled nylon 6/12 resin.

• An inspection of the molding resin used to produce the discrepant parts revealed


differences in the material appearance, relative to a retained resin lot.

ASM Handbook Vol 11 Jeffrey A. Jansen“Characterization of Plastics in Failure Analysis”

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• DSC thermograms obtained on the samples

Plastic Couplings

DSC

pthat produced brittle parts showed an endotherm associated with melting of the nylon 6/12 resin.

• The results also exhibited transitions indicative of the presence of


contaminant materials• One of the resin showed a

secondary melting point at 165°C indicative of polypropylene.

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• DSC thermograms obtained on the samples

Plastic Couplings

DSC

obtained on the samples that produced brittle parts showed an endotherm associated with melting of the nylon 6/12 resin.

• The results also exhibited transitions indicative of the presence of contaminant


pmaterials

• The second sample showed a second melting transition at 260 °C -nylon 6/6 resin.

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DSC - Crystallinity

PPS shows low temperature crystallization1.5

118.54°C

244.65°C

248.45°C32.20J/g

0.5

1.0

Hea

t Flo

w (W

/g)

First Heating Run


281.31°C

265.60°C29.83J/g

114.52°C14.83J/g

-0.5

0.0

0 50 100 150 200 250 300 350Temperature (°C)Exo Up Universal V4.7A TA Instruments

Thermal Analysis608-231-1907

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DSC - Crystallinity

0.0PPS shows low temperature crystallization

272.88°C32.30J/g

-0.4

-0.3

-0.2

-0.1

Hea

t Flo

w (W

/g)

S d H i R


281.47°C-0.6

-0.5

0 50 100 150 200 250 300 350 400Temperature (°C)Exo Up Universal V4.7A TA Instruments

Second Heating Run


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DSC - Crystallinity

PE shows reduction in heat of fusion119 44°C

7119.44°C

121.38°C238.2J/g

0

1

2

3

4

5

6

Hea

t Flo

w (W

/g)

First Heating Run


133.25°C

130.21°C193.5J/g

Heat to 300°C @ 10°C/min. in N2Cool to -80°C @ 10°C/min. in N2

-5

-4

-3

-2

-1

-100 -50 0 50 100 150 200 250 300Temperature (°C)Exo Up Universal V4.7A TA Instruments


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DSC - Crystallinity

PE shows reduction in heat of fusion0

127.79°C236.3J/g

-3

-2

-1

Hea

t Flo

w (W

/g)


135.06°CHeat to 400°C @ 10°C/min. in N2-5

-4

-100 0 100 200 300 400Temperature (°C)Exo Up Universal V4.7A TA Instruments

Second Heating Run


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2 .0

POLYPROPYLENEPOLYPROPYLENE

The cooling portion of the run can be useful to compare materials – nucleation.

DSC - Crystallinity

1 .0

1 .5

Hea

t Flo

w (W

/g)

WITH NUCLEATING AGENTS

POLYPROPYLENEWITHOUT NUCLEATING AGENTS

-1.0

-0.5

0.0

Hea

t Flo

w (W

/g)

Crystallization during the cooling run

0 .0

0 .5

4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0 1 6 0T e m p e ra tu re (°C )E xo U p

-1.560 80 100 120 140 160 180 200

Temperature (°C)Exo Up


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Molecular degradation alters thermal transitions0 .3

F a ile d S a m p le– – – – – – – M o ld in g R e s in– – – – – – –

DSC - Degradation

1 4 3 3 0 °C (I)

1 4 9 .1 5 °C (I)-0 .0 4 3 4 5 W /g

0 .1

0 .2

Hea

t Flo

w (W

/g)

g

1 4 3 .3 0 C (I)-0 .0 4 9 7 2 W /g

0 .00 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0

T e m p e ra tu re (°C )E xo U p U n iv e rs a l V 4 .7 A T A In s t ru m e n ts

Reduction in Tg due to molecular degradation


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Molecular degradation alters thermal transitions

DSC - Degradation

Reduction in Tm due to molecular degradation


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Oxidative Induction Time (OIT)S am ple : S am ple 1S ize : 6 .4850 m gM ethod : C us tom

D S C R un D ate : 26 -F eb-2014 11 :21Ins trum ent: D S C Q 2000 V 24 .10 B u ild 1

DSC – Oxidative Stability

7.80m in179.83°C

18.65m in

100

150

200

Tem

pera

ture

(°C

)

-1

0

1

2

Hea

t Flo

w (W

/g)

7 .05m in169.98°C

0

50

T

-3

-2

0 5 10 15 20 25 30Tim e (m in)Exo U p Universa l V4 .5A TA Instrum ents


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1.0

1.2 Control Part––––––– Failed Part–––––––

DSC – Oxidative Stability

0.2

0.4

0.6

0.8

Hea

t Flo

w (W

/g)

13.18min0.22min

-0.2

0.0

0 5 10 15 20Time (min)Exo Up Universal V4.7A TA Instrum ents

Antioxidant still presentAntioxidant consumed


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DSC

DSC Limitations • Materials with similar melting points cannot be • Materials with similar melting points cannot be

distinguished:nylon 6 & poly(butlylene terephthalate) polypropylene & polyacetal copolymer


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THERMOGRAVIMETRIC ANALYSIS (TGA)


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TGA

Thermogravimetric analysis (TGA) is a thermal analysis technique that measures the amount analysis technique that measures the amount and rate of change in the weight of a material as a function of temperature or time under conditions of a controlled atmosphere. These weight changes include decomposition, dehydration and oxidation dehydration, and oxidation.


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Mechanisms of Weight Change in TGA

W ight L

TGA

• Weight Loss:– Decomposition: The breaking apart of chemical bonds.– Evaporation: The loss of volatiles with elevated temperature.– Reduction: Interaction of sample to a reducing atmosphere

(hydrogen, ammonia, etc).– Desorption.

• Weight Gain:Oxidation: Interaction of the sample with an oxidizing – Oxidation: Interaction of the sample with an oxidizing atmosphere.

– Absorption.

All of these are kinetic processes (i.e. there is a rate at which they occur).


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TGA is employed in problem solving and research

TGA

to evaluate composition and thermal stability. TGA is used to determine characteristics such as:

•the level of organic and inorganic components in materialsvolatiles content


•volatiles content•degradation and decomposition temperatures

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TGA


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TGA


ASM Handbook Vol 11 Jeffrey A. Jansen“Characterization of Plastics in Failure Analysis”

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TGA Samples TGA Experiments

TGA

• Intractable Solid• Powder• Liquid• Gas• Typically 10-25 mg

• Multiple pan types - typically platinum

• Heating capability to 1200 °C• Variable heating rate - :

typically 20 °C/min.• Variety of atmosphere gases –Typically 10 25 mg y p g

typically nitrogen then air


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TGA Applications

TGA

• Quantitative formulation information: • Polymer• Plasticizer• Fillers - carbon black and mineral fillers


• Modifiers• Assessment of thermal stability

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TGA

Quantitative Formulation Information


TA Instruments

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TGA

• 1st Step CaC2O4•H2O (s) CaC2O4 (s) + H2O (g)

Calcium Oxalate Monohydrate Calcium Oxalate

• 2nd Step CaC2O4 (s) CaCO3 (s) + CO (g) Calcium Oxalate Calcium Carbonate

• 3rd Step CaCO3 (s) CaO (s) + CO2 (g)Calcium Carbonate Calcium Oxide


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TGA

Quantitative Formulation Information


TA Instruments

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TGA

Polycarbonate / Acrylic Blend

Relative Blend Information


Thermal Analysis of PolymersM.P. SepeRAPRA Technology

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TGA

Sample: MRP Orignal TGA Run Date: 09-Dec-2015 19:42

Formulation Information

Unkno n R bber Material

22.85% Plasticizer(4.00mg)

36.22% Polymer(6.34mg)

481°C

Heat to 650°C @ 20°C/min in N2Cool to 500°CHeat to 1000°C @ 20°C/min in Air

0.4

0.6

0.8

1.0

Der

iv. W

eigh

t (%

/°C

)

40

60

80

100

Wei

ght (

%)

Size: 17.4940 mgMethod: N2/Air

TGA Instrument: TGA Q500 V20.10 Build 36Unknown Rubber Material


25.41% Carbon Black(4.44mg)

Residue:15.52%(2.72mg)

367°C

0.0

0.2

D

0

20

0 200 400 600 800 1000Temperature (°C) Universal V4.7A TA Instruments

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• Housing for Electrical Appliance

Appliance Housing

TGA

Appliance

• Failures Occurred During Assembly - Insertion of Screws Into Bosses

• Failures Limited to a Production Lot

• Injection Molded


• Acrylonitrile:butadiene:styrene(ABS) Resin - Grade Unknown

• Regrind Used in ProductionSource: “Testing Beats Talking”, Appliance Manufacturer, Business News Publishing Company, J.A.. Jansen, March 2001, pg. 21-24.

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• Separation of ABS and PBT Resins

Appliance Housing

TGA

PBT Resins

• Approx. 24% PBT


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• Molded plastic clips exhibited low strength

Plastic Clips

TGA

gand failed QC testing.

• Specified to be molded from a 10% aramid fiber and 15% PTFE modified polycarbonate resin .


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• Molded plastic clips exhibited low strength

Plastic ClipsSample: HolsterSize: 14.7790 mg TGA

File: T:\_TGA\TEC008525.001Operator: MKKInstrument: TGA Q500 V20.10 Build 36Control Sample

TGA

gand failed QC testing.

• Specified to be molded from a 10% aramid fiber and 15% PTFE modified polycarbonate resin .

• TGA testing of the control sample produced

0.6036% volatiles(0.08921mg)

96.83% wt loss in N2(14.31mg)475.77°C

592.32°C

1.5

2.5

3.5

Der

iv. W

eigh

t (%

/°C

)

40

60

80

100

Wei

ght (

%)


complicated weight loss profile consistent with stated material.

2.063% wt loss in air(0.3049mg) Residue:

0.5006%(0.07398mg)

heat 20°C/min to 900°C, N2equilibrate at 500°Cheat 20°C/min to 1000°C

-0.5

0.5

0

20

0 200 400 600 800 1000

Temperature (°C) Universal V4.5A TA Instruments

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• TGA testing of the control sample produced

Plastic ClipsWeight Loss Profile Comparison

TGA

p pcomplicated weight loss profile consistent with stated material.

• Failed part material showed different profile.

• Lack of aramid fibers.35

55

75

95

Wei

ght (

%)

Holster––––– · Resin––––––– Clip–– –– –

Control Samples

Failed Part


-5

15

0 200 400 600 800 1000


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TGA - Degradation

Molecular degradation alters weight loss profiles


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TGA

Thermal Stability


TA Instruments608-231-1907

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TGA Limitations

TGA

• Compositional data limited to major ingredients

• Limited by thermal separation


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TGA Curves are not ‘Fingerprint’ CurvesBecause most events that occur in a TGA are kinetic in

TGA

• Pan material type shape and size

Because most events that occur in a TGA are kinetic in nature (meaning they are dependent on absolute temperature and time spent at that temperature), any experimental parameter that can effect the reaction rate will change the shape / transition temperatures of the curve. These things include:

• Pan material type, shape and size.• Ramp rate.• Purge gas.• Sample mass, volume/form and morphology.


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THERMOMECHANICAL ANALYSIS THERMOMECHANICAL ANALYSIS (TMA)


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TMA is a thermal analysis technique that

TMA

TMA is a thermal analysis technique that measures linear or volumetric dimensional changes within a sample as a function of temperature or time.


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TMA is a thermal analysis technique that measures linear or volumetric dimensional changes within a sample as a

TMA

function of temperature or time. The technique can be used to measure different physical attributes of the sample including:• Coefficient of thermal expansion (CTE) • Softening temperature or glass transition temperature• Melting temperature


• Melting temperature• Crystalline to amorphous transition temperatures• Tensile or compression modulus

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TMA


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ASM Handbook Vol 11 “Characterization of Plastics in Failure Analysis”Jeffrey A. Jansen,

TMA


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TMA Samples TMA Experiments

TMA

• Intractable Solid – must be of uniform geometry and have two flat and parallel sides

• Fibers and films

• Variety of probes depending on experiment

• Temperature range: subambient to 1000 °C

• Variable heating rate –typically 5 °C/min.

• Variety of purge gases –typically inert (N2)

• Compressive force


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TMA Probe Types

TMA


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TMA Applications to Failure Analysis

TMA

• Assessment of molded-in residual stress• Coefficient of thermal expansion • Determination of material transitions• Chemical compatibility


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TMA

Sample: 230 overmold sample 3 TMA Run Date: 29-Apr-2011 10:32

Coefficient of Thermal Expansion

120.00°CAlpha=262.6µm/(m·°C)

100

150

200

250

ensi

on C

hang

e (µ

m)

Sample: 230 overmold sample 3Size: 6.4070 mmMethod: 0.02N-5C-150C

TMA Run Date: 29 Apr 2011 10:32Instrument: 2940 TMA V2.4E


40.00°C

Heat to 150°C @ 5°C/min. in N2-50

0

50Dim

e

20 40 60 80 100 120 140 160Temperature (°C) Universal V4.7A TA Instruments

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TMA

• Unfilled polycarbonate resin

• Insert molded in

Chemical Sensor

• Insert molded in conjunction with a steel tube

• Service includes ambient temperature exposure

• Stress cracking over time


Failure Analysis of a Polysulfone Flow Sensor Body – A Case StudyJeffrey A. JansenPractical Failure Analysis Volume 1(2) April 2001

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TMA

• Coefficient of thermal expansion normal for

Chemical Sensor

expansion normal for polycarbonate

• No signs of molded-in stress

• Disparity with coefficient of thermal expansion for steel insert

PC

Steel


Failure Analysis of a Polysulfone Flow Sensor Body – A Case StudyJeffrey A. JansenPractical Failure Analysis Volume 1(2) April 2001

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TMA

Glass Transition Temperature


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TMA

Glass Transition Temperature


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TMA

Glass Transition Temperature / Cure

Phenolic Resin Post Cure


Thermal Analysis of PolymersM.P. SepeRAPRA Technology

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• Unfilled polycarbonate resin• Resin grade and processing

Vehicle Grille

TMA

• Resin grade and processing conditions not known

• Steel logo nameplate secured to part with threadlocker

• Manufacturing change resulted in different adhesive


• Anaerobic phenolic / methacrylate adhesive

• Failures took place while in storage

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• Unfilled polycarbonate resin

• Resin grade and processing

Vehicle Grille

TMA

• Resin grade and processing conditions not known

• TMA indicated the presence of molded-in residual stress in the failed grille.


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TMA Limitations

TMA

• Sample preparation – need to flat / parallel surfaces


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DYNAMIC MECHANICAL ANALYSIS(DMA)


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DMA

• Dynamic mechanical analysis (DMA)• Technique in which a small deformation is applied q pp

to a sample in a cyclic manner. This allows the material’s response to stress, temperature, frequency and other values to be studied.

• Assesses the proportion of elastic and viscous components in a polymer

• Determines the factors that change this balance • How will a material perform in a given application

environment


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DMA

Applies a sinusoidal deformation to a sample of known geometry. The sample can be subjected by a known geometry. The sample can be subjected by a controlled stress or a controlled strain. For a known stress, the sample will then deform a certain amount. How much it deforms is related to its stiffness (modulus). A force motor is used to generate the sinusoidal wave and this is transmitted to the sample via a drive shaft.


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DMA

Elastic System Viscous System


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DMA Methodology


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DMA Methodology


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DMA

DMA applies an oscillatory load to a sample to pp y pevaluate the strain response to stress.


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DMA

Viscoelastic System


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DMA

For a viscoelastic material, the stress and strain will be out of phase by some quantity known as the phase angle – common referred to as delta (δ).

Small phase angle – highly elasticLarge phase angle – highly viscous


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DMA

Complex response of the material is resolved into:

E’ elastic or storage modulus (tensile)The ability of the material to store energy.

E’’ viscous or loss modulus (tensile)The ability of the material to dissipate energy.


Tan δ E’’ / E’Measure of material damping

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TEMPERATURE DEPENDENCY


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DMA Temperature Sweep

Storage Modulus• Contribution of the elastic component in the • Contribution of the elastic component in the

polymer – store energy under conditions of stress

• Stiffness of the material – resistance to strain


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14000

Sample: Nylon 6 - 30% GFSize: 35.0000 x 12.0600 x 3.0500 mmMethod: temp Ramp -40 to 175 C at 2c/mi

DMA Run Date: 31-Dec-2013 10:46Instrument: DMA Q800 V20.9 Build 27

DMA - Modulus

• Modulus over a temperature

g

0.00°C9133MPa

25.00°C6611MPa

6000

8000

10000

12000

Sto

rage

Mod

ulus

(MP

a)

range

100.00°C3728MPa

2000

4000

-50 0 50 100 150Temperature (°C) Universal V4.7A TA Instruments


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14000

Sample: Nylon 6 - 30% GFSize: 35.0000 x 12.0600 x 3.0500 mmMethod: temp Ramp -40 to 175 C at 2c/mi

DMA Run Date: 31-Dec-2013 10:46Instrument: DMA Q800 V20.9 Build 27

DMA - Modulus

• Modulus over a temperature

g

0.00°C9133MPa

25.00°C6611MPa

6000

8000

10000

12000

Sto

rage

Mod

ulus

(MP

a)

range• Superior to

tensile testing

100.00°C3728MPa

2000

4000



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DMA - Modulus

• Comparison of two materials 10000

PC–––––––PC / PBT Bl d• Modulus cross-

over

100

1000

Sto

rage

Mod

ulus

(MP

a)

PC / PBT Blend–––––––


1

10


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DMA - Molecular Structure

• Structural information

Crosslinked

Semi-crystalline

Tg


Amorphous Tg

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DMA - Molecular Structure

2500

3000 Polycarbonate––––––– Nylon 6–––––––

• Amorphous vs. Semi-crystalline –t t l

Amorphous

1000

1500

2000

2500

Sto

rage

Mod

ulus

(MP

a)

structuralp

TgTg

0

500



Semi-crystalline

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DMA - Viscous Properties

Loss Modulus• Contribution of the viscous component in the • Contribution of the viscous component in the

polymer – flow under conditions of stress• Creep / cold flow or stress relaxation• Not the derivative of the storage modulus


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DMA - Viscous Properties

Tan Delta• Comparison of polymers where storage and • Comparison of polymers where storage and

loss moduli are subject to change because of alterations on composition, geometry, or processing conditions

• Index of viscoelasticity• Unitless / dimensionless


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DMA - Glass Transition Temperature

• DMA provides best measurement technique –direct assessment of molecular changes within the materialmaterial

• Onset of sharp reduction in storage modulus –practical effect of temperature on load-bearing capabilities

• Loss modulus peak temperature – corresponds well with other thermal analysis techniques, ASTM D 4065ASTM D 4065

• Tan Delta peak temperature - material has highest ratio of flow to storage – the point of highest realtive viscous contribution


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DMA - Glass Transition Temperature

• Polycarbonate• Determining the 5003000

Sample: PCSize: 35.0000 x 12.9100 x 3.3100 mmMethod: temp ramp -60 to 175 C at 2c/mi

DMA Run Date: 06-Feb-2015 11:32Instrument: DMA Q800 V21.1 Build 51

glass transition temperature (Tg)

138.86°C

146.62°C152.84°C

1.0

1.5

2.0

Tan

Del

ta

200

300

400

Loss

Mod

ulus

(MP

a)

1000

1500

2000

2500

Sto

rage

Mod

ulus

(MP

a)


0.5

0

100

0

500

50 100 150Temperature (°C) Universal V4.7A TA Instruments

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DMA - Alloy or Blend

• PPO / PS Resin Blend 50400

Sample: Noryl 731 tensile barSize: 35.0000 x 12.4700 x 3.0700 mm DMA

File: T:\_DMA\2012\ENB013385P.405Operator: MKKInstrument: DMA Q800 V20.9 Build 27

22.00°C330.3kPSI

144.20°C

temperature rampheat 2°C/min from 15°C to 150°C40 um at 1 Hzdual cantilever 0.4

0.6

0.8

1.0

Tan

Del

ta

20

30

40

Loss

Mod

ulus

(kPS

I)

200

300

Stor

age

Mod

ulus

(kPS

I)Tg 215°C

Tg 100°C


0.2

0

10

0

100

0 20 40 60 80 100 120 140 160


Resin Alloy: Single Tg 144 °C

Resin Blend: Two Tg

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DMA - Impact Resistance

• Secondary transition –

Sample: ABSSize: 35.0000 x 9.9400 x 3.7000 mmMethod: temp Ramp to 120 C at 2c/min

DMA Run Date: 06-Sep-2011 13:52Instrument: DMA Q800 V20.9 Build 27transition short range molecular mobility

• Energy b i

-4.26°C

2.39°C

0.02

0.03

0.04

Tan

Del

ta

40

60

80

100

Loss

Mod

ulus

(MP

a)

1000

1500

2000

2500

3000

Stor

age

Mod

ulus

(MPa

)

p p

absorption – impact properties


0.01

0

20

0

500

1000S

-50 -25 0 25 50 75 100Temperature (°C) Universal V4.7A TA Instruments

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TIME DEPENDENCY


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DMA - Creep

Creep is…..

the tendency of a solid material to deform permanently under the influence of constant stress (tensile, compressive, shear, or flexural). It occurs as a function of time through extended exposure to of time through extended exposure to levels of stress that are below the yield strength of the material.


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DMA - Creep

• Low to moderate forces exerted over an extended time → lower ductility. Can result in brittle fracture in

ll d til l tinormally ductile plastics• Inherent viscoelastic nature of polymers leads to time

dependency• Prolonged static stresses lead to a decay in apparent

modulus through localized molecular reorganization of polymer chainspolymer chains

• At stresses below the yield point molecular reorganization includes disentanglement as there is no opportunity for yielding


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Time and Temperature

Time and Temperature phave the same effect

on Plastics


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1.0

1.5

2.0

Tan

Del

ta

200

300

400

Loss

Mod

ulus

(MP

a)

1000

1500

2000

2500

Sto

rage

Mod

ulus

(MP

a)

0 .5

0

100

0

500

-50 0 50 100 150Tem perature (°C) Universal V4.7A TA Instrum ents


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1.0

1.5

2.0

Tan

Del

ta

200

300

400

Loss

Mod

ulus

(MP

a)

1000

1500

2000

2500

Sto

rage

Mod

ulus

(MP

a)

0 .5

0

100

0

500

-50 0 50 100 150Tem perature (°C) Universal V4.7A TA Instrum ents


TIME – Scale Unknown

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DMA-TTS

3000

Sample: PolyacetalSize: 35.0000 x 12.4800 x 3.1200 mmMethod: Creep TTS

DMA Run Date: 18-Aug-2015 15:15Instrument: DMA Q800 V21.1 Build 51Time-Temperature

Superposition• Multiple fifteen-

1000

1500

2000

2500

Flex

ural

Mod

ulus

(MP

a)

minute determinations for at isothermal conditions

• From 10 to 145°C increments of 5°C

• Evaluations conducted using a


0

500

0 20 40 60 80 100 120 140 160Temperature (°C) Universal V4.7A TA Instruments

dual cantilever configuration

• Stress of 1.9 MPa

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DMA - Creep Projection

2000

2500

Apparent Modulus v. TimePolyacetal

• Master curve as semi-log

l t

0

500

1000

1500

Appa

rent M

odulus (M

Pa) Creep at 25 °Cplot


0.001 0.01 0.1 1 10 100 1000 10000 100000Time (hours)

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100

PolyacetalTensile Stress ‐ Strain at 25 °C Stress /

StrainModulus

• Tensile properties to

t bli h

20

30

40

50

60

70

80

90

Stress (p

si)

Stress (M

Pa)

Yield

Proportional Limit

establish modeling parameters


0

10

20

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0Strain (%)

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6 500

7.500

8.500Polyacetal‐ Strain v. Time

Creep at 25 °C15 MPa

• Use stress to d t i

‐0.500

0.500

1.500

2.500

3.500

4.500

5.500

6.500

0.001 0.01 0.1 1 10 100 1000 10000 100000

Strain (%

)

Time (hours)

20 MPa

determine strain over time

• Project time to cracking


Projected time to cracking:15 MPa: >200,000 hours (22.8 years)20 MPa: 45,700 hours (5.2 years)

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Comparing Creep Resistance

2000 Eastar GN071––––––– Xenoy 5720U–––––––PC+PBTCopolyester

1000

1500

Sto

rage

Mod

ulus

(MP

a)


0

500

25 75 125 175Temperature (°C) Universal V4.7A TA Instruments

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Comparing Creep Resistance

250000

300000

50000

100000

150000

200000

Appa

rent M

odulus (p

si)

Apparent Modulus v. TimeCreep at 25 °C

PC+PBTCopolyester


00.001 0.01 0.1 1 10 100 1000 10000 100000

Time (hours)

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Q ti ?Questions?


Thermal Analysis [email protected]

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