Li Liu presentation

Tailoring the beta transition in epoxy resins: Anhydride

cured alternativesLi Liu

Supervisor: Dr Joel Foreman

Contents• Background and Aim• Literature review• Experimental procedure• Results and Discussion• Conclusions• Future work• Acknowledgement

Background and AimEpoxy resin: Epoxy group Popular material Good properties BrittlePhase transition: Crankshaft model[1]

Properties

[1] Perkin Elmer, “Dynamic Mechanical Analysis Basics : Part 2 Thermoplastic Transitions 46 and Properties,” Dma, pp. 1–6, 2007.

DGEBA

Background and AimEpoxy resin: Popular material High Young’s modulus Low shrinkage BrittlePhase transition: Properties Crankshaft model[1]

Molecule motion

[1] Perkin Elmer, “Dynamic Mechanical Analysis Basics : Part 2 Thermoplastic Transitions 46 and Properties,” Dma, pp. 1–6, 2007.

Background and AimAim:

Investigate the cause of beta transition of epoxy resin by changing different combination of epoxy resin and curing agent

Discuss glass transition to analyze determine beta transition

Literature reviewGlass transition[1]: Stiff chemical structure of moleculeCrosslinks

Beta transition:Phenyl ring[2]

Glycidyl ether segment[3]

Combination of flipping phenyl ring and glycidyl ether segment[4]

[1] J. M. G. Cowie and V. Arrighi, “Polymers: Chemistry and Physics of Modern Materials,” in Polymers: Chemistry and Physics of Modern Materials, 2007, p. 463.[2] M. Ochi, H. Iesako, and M. Shimbo, “Mechanical relaxation mechanism of epoxide resins cured with diamines,” Polymer (Guildf)., vol. 26, no. 3, pp. 457–461, 1985.[3] J. G. Williams and O. Delatycki, “Transitions of the hydrogen bond in epoxy–diamine networks,” J. Polym. Sci. Part A-2, vol. 8, pp. 295–304, 1970.[4] W. JOHN G, “the Beta Relaxation in Epoxy Resin-Based Networks

Experimental procedureResins: • Diglycidyl ether of bisphenol A (DGEBA)• Triglycidyl p-amino phenol (p-TGAP)• Triglycidyl m-amino phenol (m-TGAP)Hardeners:• 4,4’-disamino-diphenylsulphone (4,4’-DDS)• Methyl anhydride (NMA or MNA)Initiator:• Benzyl dimethyl amine (BDMA)Experimental method:• Dynamic mechanical analysis (DMA)• Differential scanning calorimetry (DSC)

m-TGAP

P-TGAP

DGEBA


4,4’-DDS

NMA or MNA

BDMA

Experimental procedureResins: • Diglycidyl ether of bisphenol A (DGEBA)• Triglycidyl p-amino phenol (p-TGAP)• Triglycidyl m-amino phenol (m-TGAP)Hardeners:• 4,4’-disamino-diphenylsulphone (4,4’-DDS)• Methyl anhydride (NMA or MNA)Initiator:• Benzyl dimethyl amine (BDMA)Experimental method:• Differential scanning calorimetry (DSC)• Dynamic mechanical analysis (DMA) PerkinElmer DMA 8000

PerkinElmer DSC 8500


Beta and glass transition in DMA results

-150.0 -50.0 50.0 150.0 250.00.00

0.20

0.40

0.60

0.80

1.00

Temperature

Tan

delta

glass

β

Results and DiscussionAppearance: DGEBA system appear

yellow

TGAP system appear orange or red

4,4’-DDS system appear darker than NMA system

With increasing percentage of epoxy resin, colour become lighter

DGEBA TGAP m-TGAP

4,4’- DDS

NMA BDMA

(50:90:1)

NMA BDMA

(75:90:1)

NMA BDMA

(100:90:1)

Appearance of samples

Results and DiscussionDSC: For main five samples, all curing degree are above 90% which means the samples

are cured

For the discussion of beta transition, the effects of glycidyl ether segments could be ignored

DGEBA/ 4’4DDS

DGEBA/ NMA/BDMA

TGAP/ 4’4DDS

p-TGAP/ NMA/BDMA

m-TGAP/ 4’4DDS

Degree of cure/%

97.81 92.02 97.10 95.10 99.57

Results and DiscussionDMA for samples which show full glass transition: With increasing frequency, the temperature of glass transition increases With increasing frequency, the temperature of beta transition ascends Higher temperature could provide more energy to support high-frequency

motivation

-150.0 -50.0 50.0 150.0 250.00.00.20.40.60.81.0

Tan Delta1. Tan Delta5. Tan Delta10.Tan Delta50.

Temperature

Tan

delta

-150.0 -100.0 -50.0 0.0 50.00.01

0.03

0.05

0.07

0.09

Tan Delta1. Tan Delta5. Tan Delta10.Tan Delta50.

Temperature

Tan

delta

DMA results of DGEBA/4,4’-DDS Beta transition of DGEBA/4,4’-DDS

Results and DiscussionDMA for samples which show full glass transition: With increasing frequency, the temperature of glass transition increases With increasing frequency, the temperature of beta transition ascends Higher temperature could provide more energy to support high-frequency

motivation

Glass temperature of main samples Beta temperature of main samples

0 0.5 1 1.5 2 2.5 3 3.5 4150170190210230250270290

DGEBA/4,4'-DDS DGEBA/NMA p-TGAP/4,4'-DDSp-TGAP/NMA m-TGAP/4,4'-DDS

Ln frequency (Hz)

Tem

pera

ture

0 0.5 1 1.5 2 2.5 3 3.5 4

-75

-55

-35

-15

DGEBA/4,4'-DDS DGEBA/NMA p-TGAP/4,4'-DDSp-TGAP/NMA m-TGAP/4,4'-DDS

Ln frequency (Hz)

Tem

pera

ture

Results and DiscussionDMA results comparison for main samples: 4,4’-DDS systems and TGAP systems have higher glass temperature than NMA

systems and DGEBA systems p-TGAP systems has higher glass temperature than m-TGAP

-160.0 -60.0 40.0 140.0 240.00.00.20.40.60.81.01.21.4

DGEBA 44DDS p-TGAP NMA (50:90:1) DGEBA NMAp-TGAP 44DDS m-TGAP 44DDS m-TGAP NMA (50:90:1)

Temperature

Tan

delta

Glass transition of main samples

4,4’-DDS has two phenyl rings which lead to stiffer chemical structure and results in higher glass transitionTGAP has three functional groups which lead to more crosslinks and results in higher glass transitionThe chemical structure of m-TGAP leads to less crosslinks in post-cured process which result in lower glass transition

Results and DiscussionDMA results comparison for main samples: 4,4’-DDS system has larger beta transition than NMA system p-TGAP system has larger beta transition than m-TGAP

-160.0 -110.0 -60.0 -10.0 40.00.00

0.02

0.04

0.06

0.08

0.10


Temperature

Tan de

lta

Beta transition of main samples

Two phenyl rings in 4,4’-DDS leads to larger beta transitionThe chemical structure of m-TGAP hinder the effect of phenyl ringThe influence of anhydride is still unknown

Results and DiscussionDMA results comparison for different ratio: With increasing proportion of epoxy resin, temperature of glass transition decreases There is no rule about different ratio and beta transitionThe samples of 75:90:1 and 100:90:1 may be not curedThe excess of epoxy resin may hinder crosslinking

-200.0 -100.0 0.0 100.0 200.00.0

0.2

0.4

0.6

0.8

1.0

50:90:1 75:90:1 100:90:1

Temperature

Tan

delta

-200.0 -150.0 -100.0 -50.0 0.00.01

0.02

0.03

0.04

0.05

0.06

50:90:1 75:90:1 100:90:1Temperature

Tan

delta

Glass transition of different ratio sample Beta transition of different ratio sample

Results and DiscussionDMA results comparison for different further post cure: With increasing time of further post cure, glass temperature ascend No regularity about beta transition and further post-cured timeFurther post curing result in more crosslinks which could increase glass temperatureThe samples are not homogeneous

-200 -100 0 100 200 3000.0

0.5

1.0

1.5

2.0

no further post cure further post cure 2 hrsfurther post cure 4 hrs

Temperature

Tan

delta

-200.0 -150.0 -100.0 -50.0 0.0 50.00.02

0.03

0.04

0.05

no further post cure further post cure 2 hrsfurther post cure 4 hrs

Temperature

Tan

delta

Glass transition of different time of post cure Beta transition of different time of post cure

Results and DiscussionDMA results comparison for rescanning: After rescanning, temperature of glass transition increase After rescanning, area of beta transition decreaseRescanning provide high temperature for sample to post cureThe samples were oxidized when they were scanned

-150.0 -50.0 50.0 150.0 250.00.00.10.20.30.40.50.60.70.8

scan rescan

Tan

delta

Glass transition of p-TGAP/NMA (50:90:1)

-150.0 -50.0 50.0 150.00.0

0.2

0.4

0.6

0.8

1.0

scan rescan

Temperature


-150.0 -50.0 50.0 150.0 250.00.0

0.2

0.4

0.6

0.8

1.0

scan rescan

Glass transition of m-TGAP/NMA (50:90:1)

Results and DiscussionDMA results comparison for rescanning: After rescanning, temperature of glass transition increase After rescanning, area of beta transition decreaseRescanning provide high temperature for sample to post cureMore crosslinks may hinder the motivation of small molecules which result in

smaller be transition

-200.0 -100.0 0.00.00

0.01

0.02

0.03

0.04

0.05

scan rescan

Tan

delta

-200.0 -100.0 0.00.00

0.01

0.02

0.03

0.04

0.05

scan rescan

Temperature-200.0 -100.0 0.0

0.00

0.01

0.02

0.03

0.04

0.05

scan rescan

Beta transition of p-TGAP/NMA (50:90:1) Beta transition of p-TGAP/NMA (75:90:1) Beta transition of m-TGAP/NMA (50:90:1)

Conclusion

• Stiffer chemical structure and more crosslinks lead to higher temperature of glass transition

• Phenyl rings in chemical structure contribute to beta transition

Future work

• Determine the correct ratio and curing process of TGAP/NMA/BDMA systems

• Change one factor when determine the effect of anhydride (for example: choose an anhydride hardener which has two phenyl ring or an amine-hardener which has no phenyl ring)

Acknowledgement

I would like to thank my supervisor, Dr Joel Foreman, for his guidance, encouragements, and patience throughout the project and presentation.

I would also like to thank Roderick Ramsdale-Capper and Ben Holmes, for their help throughout the project and the training for casting epoxy resins, DMA scanning and DSC. And the useful advice on presentation from Olga Amariutei.

In addition, I would like to appreciate the help of all staffs in the lab.

Thank you for listeningAny questions?

-150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.00.000

0.200

0.400

0.600

0.800

1.000

Temperature

Tan

delta

glass

β

Beta and glass transition in DMA results

Phase transition

Molecule motion

DGEBA TGAP m-TGAP

4,4’-DDS

NMA BDMA

(50:90:1)

NMA BDMA

(75:90:1)

NMA BDMA

(100:90:1)

Appearance of samples

-150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.00.0

0.2

0.4

0.6

0.8

1.0

Tan Delta1. Tan Delta5. Tan Delta10. Tan Delta50.Temperature

Tan

delta

DMA results of DGEBA/4,4’-DDS

-150.0 -130.0 -110.0 -90.0 -70.0 -50.0 -30.0 -10.0 10.0 30.0 50.00.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

Tan Delta1. Tan Delta5. Tan Delta10. Tan Delta50.Temperature

Tan

delta

Beta transition of DGEBA/4,4’-DDS

Glass temperature of main samples

0 0.5 1 1.5 2 2.5 3 3.5 4150

170

190

210

230

250

270

290

DGEBA/4,4'-DDS DGEBA/NMA p-TGAP/4,4'-DDS p-TGAP/NMAm-TGAP/4,4'-DDS

Ln frequency (Hz)

Tem

pera

ture

Beta temperature of main samples

0 0.5 1 1.5 2 2.5 3 3.5 4-85

-75

-65

-55

-45

-35

-25

-15

-5

DGEBA/4,4'-DDS DGEBA/NMA p-TGAP/4,4'-DDS p-TGAP/NMAm-TGAP/4,4'-DDS

Ln frequency (Hz)

Tem

pera

ture

-200.0 -150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.00.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

50:90:1 75:90:1 100:90:1Temperature

Tan

delta

Glass transition of different ratio sample

-200.0 -150.0 -100.0 -50.0 0.00.01

0.02

0.03

0.04

0.05

0.06

50:90:1 75:90:1 100:90:1Temperature

Tan

delta

Beta transition of different ratio sample

-200.0 -150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.0 300.00.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

no further post cure further post cure 2 hrs further post cure 4 hrs

Temperature

Tan

delta

Glass transition of different time of post cure

-200.0 -150.0 -100.0 -50.0 0.0 50.00.02

0.03

0.04

0.05

no further post cure further post cure 2 hrs further post cure 4 hrsTemperature

Tan

delta

Beta transition of different time of post cure

-200.0 -150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.00.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

scan rescanTemperature

Tan

delta


-200.0 -150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.00.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0


Tan

delta


-200.0 -150.0 -100.0 -50.0 0.0 50.0 100.0 150.0 200.0 250.00.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0


Tan

delta

Glass transition of m-TGAP/NMA (50:90:1)

-200.0 -150.0 -100.0 -50.0 0.0

-0.01

0.00

0.01

0.02

0.03

0.04

0.05


Tan

delta

Beta transition of p-TGAP/NMA (50:90:1)

-200.0 -150.0 -100.0 -50.0 0.00.00

0.01

0.02

0.03

0.04

0.05


Tan

delta

Beta transition of p-TGAP/NMA (75:90:1)

-200.0 -150.0 -100.0 -50.0 0.00.00

0.01

0.02

0.03

0.04

0.05


Tan

delta

Beta transition of m-TGAP/NMA (50:90:1)

Glass transition of main samples

-160.0 -110.0 -60.0 -10.0 40.0 90.0 140.0 190.0 240.0 290.00.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


Temperature

Tan

delta

Beta transition of main samples

-160.0 -110.0 -60.0 -10.0 40.00.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10


Temperature

Tan

delta

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