characterization and properties of recycled materials · pdf fileastm 3379-75: method for...

Fraunhofer Research Institution for

Casting, Composite and Processing Technology IGCV

Correlation between micro- and macroscopic characterization of recycled carbon fibre materials

Frank Manis, Ananda Schindler, Michael Sauer and Jakob Wölling

Fraunhofer IGCVLocated in Augsburg

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Processing technology

Fraunhofer IGCVWe use synergies in these fields of research and development:

Composite technologyCasting technology

Resource efficiency in factories

Intelligent networked production

Flexible production

Networked modeling and simulation

Additive manufacturing

Hybrid composite constructions

Online process monitoring

Materials and test engineering

CFRP manufacturing engineering

Recycling

Efficiency and balancing

Molding materials

Sand and gravity die casting processes

Simulation and design of mold and cast components

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Possibilities for cooperationThe Fraunhofer-Model

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Carbon fibers are a high energy and cost intensive raw material:

Generally: recycling can be rewarding – ecological and economical

MotivationEnergy and resource intense manufacturing

Why do we need characterization technics?

Pyrolysed (550 °C, 30 minutes dwelltime) CFRP-Woven out of epoxy resin

Tensile Bending Shear

Price Optical Chemical

Sustainability Impact Electrical

Durability Mechanical Etc.

Virgin vs. Recycled carbon fibresWhat is the difference?

Fibreorientation

Fibrelength

Fibrevolumecontent

Filament Interphase

Why do we need characterization technics?

[CES Selector by Granta Design]

Why do we need characterization technics?Influences on properties by recycling

Microscopic characterizationSingle filament testing

ASTM 3379-75: Method for Tensile Strength and Young Modulus forHigh-Modulus Single-Filament Materials

Carbon fibre

Resin / Glue

Paper

Diameter

𝜎𝑥𝑥 =𝐹𝑥𝑥

𝐴=

𝐹𝑥𝑥

𝜋 𝑅²

Favimat-Single fibretensile test

Microscopic characterizationSingle filament testing

Statistic Diameter

Fibre-manufacturer Testing Parameters

Microscopic characterizationInterface – Surface Groups and Adhesion

https://en.wikipedia.org/wiki/Epoxy

Fibre Interphase Matrix

https://www.weizmann.ac.il/materials/Wagner/research

Microscopic characterizationInterface – Defects and roughness

Macroscopic characterizationStructural and textural homogeneity

Explanation of measurement:

Transmitted Light calcuation

Calculation Ø,

Calculation of average value over

e.g. 10x10 Pixel

Increasing of pixel size

fence


Homogeneity in MD is good. Steady production direction

Longer fibres result in worse homogeneities

4,61 6,15 7,0210,3411,59

7,12

16,14

34,2

Sigrafil12mm 0.1

vCF SGL12mm 1.1

vCF SGL18mm 1.2

vCF SGL36mm 1.3

Stabw MD Stabw CD

(g

rey-v

alu

e)

H

om

og

en

eit

yin

MD (Grey Value)

Homogeneityin CD

CDMD


Proof of Technology mit CT Untersuchungen und zerstörenden Zugfestigkeitsmessungen in >= 10 Studien

Fibre-orientation

Fibre-volume content

Homogeneity and defects

Microscopic and Macroscopic


Project „Izi-Direct“ starts in 2018

Development of in- and online measurement of fibre orientation in recycled fibre production via eddy current measurement

Application in textile processes (Wet- and Dry laid nonwovens)


Micro and Macroscopic viewClean doesn‘t mean clean

Pyrolysed (550 °C, 30 minutes dwell time) CFRP-Woven out of epoxy resin

Micro and Macroscopic viewClean doesn‘t mean clean

600 °C 30 minutes oxidised20,9 % O2

600 °C 30 minutes pyrolysed100 % N2

Virgin Fibers

rCFRP-CharacterizationCorrelations of fibres and couponds

rCFRP-CharacterizationCorrelations of fibres and couponds

Results and discuss ion

Enhanced material failure effects

Strength of composites as a function of single fibre degradation

Char, voids, matrix rich regions, intra tow voidslead to increase failure

Maximum rCFRP degradation -27,78 % onwoven and -41,37 % on unidirectional material

-15% e.g. additional missorientation due handling

-2%-12% e.g. Char, voids, matrix rich regions, intra tow voids

-18% e.g. Char, voids, matrix rich regions, intra tow voids

U (V) U/500/30 U/500/60 W (V) W/500/60 W/475/30

0

20

40

60

80

100

120

140

rCF

/vC

F s

trength

[%

]

Materials

rCF/vCF strength (SF)

rCF/vCF strength (rCFRP)

SUMMARY AND OUTLOOKWHY DO WE NEED CHARACTERIZATION TECHNICS?

Recycling of composites leads to new questions that are not answered at the moment

Macroscopic properties are depending on microscopic effects like fibreproperties, char content, voids, fibre defects

New testing methologies has to be implmeneted for prodcuts out of rCF

Online measurment of rCF properties necessary for future application

Recycling of CompositesContact us

Fraunhofer IGCVAm Technologiezentrum 286159 Augsburg, Germany

Dipl.-Ing. Frank Manis

Phone +49 821 / [email protected]

characterization and properties of recycled materials · pdf fileastm 3379-75: method for...

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