SuCoHS project, Grant Agreement N° 769118

9th EASN International Conference on Innovation in Aviation and Space

L. Amirova, F. Schadt, C. Brauner, M. Grob

University of Applied Sciences and Arts Northwestern Switzerland

03-06.09.2019, Athens, Greece

Properties and structure of Cyanate Ester/Polyethersulfone composites

01/10/2019 2

Requirements for the material development

Glass transition temperature > 335°C

Fracture toughness > 0.85 MPa·m1/2

Curing temperature < 185°C

01/10/2019 3

Comparative properties of advanced resins

[Iredale, R. J., Ward, C., & Hamerton, I. (2017). Modern advances in bismaleimide resin technology:

a 21st century perspective on the chemistry of addition polyimides. Progress in Polymer

Science, 69, 1-21.]

01/10/2019 4

Toughening mechanisms

[Wang, J., Liu, R., & Jian, X. (2017). Introduction to

epoxy/thermoplastic blends. Handbook of Epoxy Blends, 429-458.]

01/10/2019 5

Matrix toughening

- Phenoxy resin- Polyphenylsulfone- Acrylic polymers- Epoxy resin toughened with silica nanoparticles- Polyethersulfone (different grades, functionalization,

molecular weight)- Polyetherimide (different grades)

Interlayer toughening

- Phenoxy films- Polyetherimide films

Toughening approaches. Overview

Tg~220°C

Tg~90°C

01/10/2019 6

Investigation of molecular weight, functionalization and content of polyethersulfone

(PES) on thermal and mechanical properties of cyanate ester formulations

Development of accelerated cyanate ester formulation allowing curing at 180°C

Prepreg manufacturing based on the developed formulation

Demonstrator part manufacturing

Objectives of the work

01/10/2019 7

Cyanate ester PT-30 (CE)

T(°C)

time (hour)

260

200

150

Conventional heating cycle

01/10/2019 8

Cure kinetic parameters of PT-30 CE

𝑑𝛼

𝑑𝑡= 𝐴1 exp −

𝐸1𝑅𝑇

1 − 𝛼 𝑛1 + 𝐴2 exp −𝐸2𝑅𝑇

𝛼𝑚 1 − 𝛼 𝑛22

1 + 𝑒𝑥𝑝𝛼 − 𝛼𝑚𝑎𝑥

𝑏

− 1

01/10/2019 9

Parameters PES 1 PES 2 PES 3

Mw, g/mol 16000 33000 42000

Particle size, µm 45 45 45

Glass transition temperature, °C 220 223 227

-OH end groups, per 100 polymer

relating units4.5 - 1.1

Polyethersulfone (PES)

01/10/2019 10

Methods

Glass transition temperature

Storage modulus

Curing temperatureand enthalpy

Cure kinetics

Fracturetoughness

Morphology

DMA Q800

(TA Instruments)

DSC 25

(TA Instruments)

Hot stage microscope

(Linkam)

Universal testing machine

(Zwick / Roell Z100 )

Laser scanning microscope

(Keyence VK-X200)

Fracture surfacemorphology

01/10/2019 11

Morphology of PT30-PES matrix

15phr PES 2 15phr PES 315phr PES 1

Droplet morphology Sea-island morphology

and phase inversion

Sea-island morphology

and phase inversion

Only certain ratios of molecular weight form a droplet morphology

10 µm 10 µm

Morphology investigation at 180°C

01/10/2019 12

Effect of PES molecular weight and functionalizationon glass transition temperature of CE formulations

20phr PES 1

drop ~35%

PT30

PT30 - 20phr PES 1

PT30 - 20phr PES 2

PT30 - 20phr PES 3

PT30 system Tg PES on,°C ΔE, MPa

Neat resin - -

20phr PES 1 241 818

20phr PES 2 231 1482

20phr PES 3 245 1505

01/10/2019 13

Fracture surface of cured PT30 - 15phr PES 1 sample

Crack propagation20 μm

Fracture toughness of PT30 - PES 1 system

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

K1

C, M

Pa

·m1

/2

PT30

PT30 PES 5%

PT30 PES 10%

PT30 PES 15%

PT30 PES 20%

K1c, M

Pa m

1/2

Increase of 132%

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

K1

C, M

Pa

·m1

/2

PT30

PT30 PES 5%

PT30 PES 10%

PT30 PES 15%

PT30 PES 20%

PT30

PT30-5phr PES

PT30-10phr PES

PT30-15phr PES

PT30-20phr PES

01/10/2019 14

Storage modulus drop at PES

Tg depending on content of PES

For 10 and 15phr PES similar

15phr PES optimum

BUT: Real Tg onset at higher

temperature

Effect of the PES content on glass transition temperatureand storage modulus behaviour of CE formulations

15-20phr PES 1

PT30

PT30 - 5phr PES 1

PT30 - 10phr PES 1

PT30 - 15phr PES 1

PT30 - 20phr PES 1

PES content,

phr

Tg PES on,°C ΔE, MPa

5 241 326

10 240 509

15 237 563

20 241 705

01/10/2019 15

PT30 - 15phr PES 1 dry

PT30 - 15phr PES 1 wet 24 h

PT30 - 15phr PES 1 wet 48 h

Influence of wet conditions on thermomechanicalproperties of PT30 – 15phr PES formulations

Conditions Tg on, °C ΔE, MPa

dry conditions 405 503

24h* 400 520

48h 400 710

* Boiling in water at 80°C

01/10/2019 16

- Estimated optimal content of PES 1 (15phr = 13wt%)

- Developed temperature conditions for impregnation

- Selected carbon fiber type T800

North Thin Ply Technology (NTPT) successfully

manufactured the prepreg based on the

toughened CE

Development of the prepreg based on the toughenedCE system

01/10/2019 17

DMA of unidirectional PT30 – 13wt% PES 1 composite

Relative Young`s modulus vs Temperature for toughened unidirectional PT30 composite

Curing cycle: autoclave 1h@150°C + 3h@200°C + freestanding postcuring 1h@260°C

100%

01/10/2019 18

𝑑𝛼

𝑑𝑡= 𝐴1 exp −

𝐸1𝑅𝑇

1 − 𝛼 𝑛1 + 𝐴2 exp −𝐸2𝑅𝑇

𝛼𝑚 1 − 𝛼 𝑛22

1 + 𝑒𝑥𝑝𝛼 − 𝛼𝑚𝑎𝑥

𝑏

− 1

CE380 – catalyzed CE system based on PT-30 resindeveloped by NTPT together with FHNWCure kinetics

01/10/2019 19

Time, h CE380 Catalyzed

PT30-15phr PES 1

3 70 73

5 75 77

Degree of cure for catalyzed CE systems at 180 °C

+ postcuring at 260 °C

Thermal properties of catalyzed toughened system

01/10/2019 20

Thermomechanical properties of catalyzed CE systems

CE380

Catalyzed PT30-15phr PES 1

01/10/2019 21

Demonstrator part manufacturing

Fully cured part in 1 hour at 260°C

01/10/2019 22

A broad variety of different potential tougheners investigated

Influence of molecular weight and functionalization of PES analyzed

Optimal content ca. of 13wt% PES for 100% of toughness increase

Temperature conditions for prepreg manufacturing established

First toughened thin-ply prepreg manufactured

Prepregs used for demonstrator part manufacturing

Conclusions

01/10/2019 23

This project has received funding from the European Union’s Horizon 2020 research and innovation

programme under grant agreement N° 769178.

Thank you for your attention