Morphology Development and Mechanical Properties … · Morphology Development and Mechanical Properties of Interfaces between Epoxy ... PEI in RTM6 at 40 ... TP film F Initial crack

Institute for Carbon Composites donated by

Morphology Development and MechanicalProperties of Interfaces between EpoxyResin and Thermoplastic Films

Philipp Bruckbauer

„A Comprehensive Approach to Carbon Composites Technology“Symposium on the Occasion of the 5 th Anniversary of the Institute for Carbon Composites

Research Campus Garching, September 11th - 12th 2014

2

Conclusion5

Mechanical Performance4

Morphology Development and Process Window3

Approach for Interface Analysis2

Introduction1

Agenda

12/09/2014 | P. Bruckbauer | Interfaces between Epoxy Resin and Thermoplastic Films

3

Conclusion5




Introduction1

Agenda


4

Thermoplastic Functional Layers


Film

CF/epoxy part

Thermoplasticclip

Joining surfaceHigh class surfaceMoisture and corrosion barrier

Integrated circuits

Interface

Reinforcement fibers

Thermoset matrix

Thermoplastic film

5

Production Process


Preforming PartInjection

Functional film

Preform

Functional film

Tool

CFRP part

Part with functional surface layer

6

Material Systems and Interface Structure


� Graded material interface� Original Material

Epoxy resin

Amorphousthermoplast

[1] G.W. Ehrenstein, Polymerwerkstoffe: Struktur – Eigenschaften – Anwendung, Carl Hanser Verlag, München, 2011

[1]

[1]

7

Conclusion5




Introduction1

Agenda


8

Approach for Interface Analysis


Hot stage experiments Resin kinetic model Mechanical tests

• Degree of cure• Degree of cure at phase separation• Time for interphase formation

• Solubility in resin system• Solubility temperature• Time of phase separation

Process cycle and interdependence of material structure and performance

• GIc• GIIc• Fracture surface

9

Conclusion5




Introduction1

Agenda


10

Solution Process


PEI in RTM6


PEI in RTM6 at 40°C Solution onset at 120°C Solution process at 130°C

Solution ProcessSolution and Phase Separation of PEI in RTM6

Solution process at 140°C

Solution process at 150°C Phase separation Interface formation Final interface

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Interface Morphology


of RTM6 - PPSU Interface

Epoxy resin 90% epoxy resin with 10% thermoplast

80% epoxy resin with 20% thermoplast

50% epoxy resin with 50% thermoplast

Transition of interface to neat thermoplast

a b c d e

a b c d e

Continuous thermoplastphase with epoxy domains

ThermoplastContinuous epoxy phase with thermoplast domainsEpoxy resin

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0

50

100

150

200

250

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 2000 4000 6000 8000 10000 12000 14000

Tem

pe

ratu

re [°C

]

De

gre

e o

f cu

re,

solu

tio

n r

ate

Time[s]

Process Window


RTM6 - PEI

TS Solution temperature α� Degree of cure at phase separation α�� Degree of cure at gelpoint

Solution rateDegree of cure Temperature

α� α��T�

2 Phases Solution 2 Phases

14

Conclusion5




Introduction1

Agenda


15

Approach for Perfomance Analysis


Analysis of fracture surfaceInterlaminar energy release rate in mode I and mode II

� Adhesion of film� Identify weak points

� Mode of failure� Interface shape

DCB sprecimen

Loading blocks

Initial crack

F

F

TP film

F

Initial crack Specimen

Compression fin

Bearing

TP film

16

Interlaminar Energy Release Rate in Mode I (GIc)


According to DIN EN 6033

0,00 200,00 400,00 600,00 800,00 1000,00 1200,00 1400,00

CF/EP/PEI

CF/EP/PES

CF/EP/PPSU

CF/EP/PSU

Ref CF/EP

GIc [J/m²]

+96%

+195%

+121%

+147%

DCB sprecimen

Loading blocks

Initial crack

F

F

TP film

CF: Carbon fiber EP: Epoxy resin

17

Interlaminar Energy Release Rate in Mode II (GIIc)


According to DIN EN 6034

0 200 400 600 800 1000 1200 1400 1600 1800 2000

CF/EP/PEI

CF/EP/PES

CF/EP/PPSU

CF/EP/PSU

Ref CF/EP

GIIc [J/m²]

+111%

+7%

+48%

+47%

F

Initial crack Specimen

Compression fin

Bearing

CF: Carbon fiber EP: Epoxy resin

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� CF/EP/PEI

Analysis of Fracture Surfaces (GIc test)


� CF/EP/PPSU

� CF/EP/PES

� Ref CF/EP � CF/EP/PSU

Matrix failure Fiber pull out, clean fiber surfaces Fiber pull out, clean fiber surfaces

Matrix failure, clean fiber surfaces Ripped out fiber bundles and matrix failure

19

Conclusion5




Introduction1

Agenda


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� Possibility for expanded material usage� Addition of functionality to state of the art

resin systems� Combination of epoxy resin and

amorphous thermoplastics with high Tgresult in a gradient interface

� Excellent mechanical performance

� Acknowledgment:The presented work was carried out in the framework of BMBF funded projects.


Conclusion

CFRP part with PEI surface

21

Technische Universität MünchenInstitute for Carbon CompositesBoltzmannstraße 1585748 Garchingwww.lcc.mw.tum.de

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Morphology Development and Mechanical Properties … · Morphology Development and Mechanical Properties of Interfaces between Epoxy ... PEI in RTM6 at 40 ... TP film F Initial crack

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