IIG – Manufacturing with Biocomposites

11

Jovana Džalto

Institut für Verbundwerkstoffe, Germany

Manufacturing with

Biocomposites

22

Content

• Who is IVW?

• Standard Applications for Natural Fiber

Composites

• Main Challenge – Mechanical Performance

• BioBuild Materials

• Manufacturing Methods

• Results

• Summary

33

Who is IVW?

Established: 1990

Budget: 35 % State, 65 % External

Internal Research Projects

New Ideas, Exploratory Work,

Fundamentals (DFG, RLP)

Governmental Research Projects

Funded Research Work

(BMBF, BMWI, EU,…)

Industrial Projects & Cooperation

New Developments in

Technology and Application,

Industry Funded Research,

Service Contracts

Cooperation-

contract with TU

Role in the BioBuild Project

Competence Field Materials Science:

Treatment of natural fibers yielding water- and

fire-resistant “green” coatings on the fibers’

surface by using bio-derived super-

hydrophobic phenalkamines and water glass

Competence Field Manufacturing Science:

Processing of biocomposite panels and

profiles in a continuous compression molding

process by using pre-impregnated textiles

developed in a previous WP

44

Standard Applications for

Natural Fiber Composites

• Since decades common use in the automotive industry for semi-

structural components

• Door panels

• Backrests

• Roof stiffenings

• New application fields

• Sports

• Furniture

• Ship building

• Usage of „Green Composites“

Mercedes E-Class Mercedes C-Class

Source: Global Hemp

Sourc

e: w

arw

ick.a

c.u

k

55

Fibers

Fiber web

Carding line Cross lapping

Mat compaction

Needling

NF-mats

• Fibers are almost randomly distributed in the non-woven

• 95 % of all natural fiber composites are manufactured by

compression molding, 5 % injection and others

• Fiber weight content in NFC not comparable to GFC

• 40 - 50 wt.-% for thermoplastic matrices

• 50 - 70 wt.-% for thermoset matrices

Standard Manufacturing Process

66

Main Challenge –

Mechanical Performance

Influence of fiber orientation in reinforcing textiles

Fiber weight fraction [%]

Stiffness

Strength

Uni-directional

natural fiber textile

Bi-directional


Multi-directional


77

Influence of density on E-Modulus

Main Challenge –

Mechanical Performance

0

1000

2000

3000

4000

5000

6000

0,75 0,8 0,85 0,9 0,95 1 1,05

Density [g/cm³]

E-M

odulu

s [

MP

a]

Low compression

low density

high porosity

High compression

high density

low porosity

Same natural fiber material

Standard

NF/PP material

for automotive

applications

88

BioBuild Materials

• Increasing the mechanical performance by using aligned fibers

• Use of furan resin as an agricultural waste product from the sugar

industry

• Use of leftovers from the cork stoppers manufacturing

cork composites

Fla

xJu

te

Bast fiber bundles Natural fiber textile

Co

rk

co

mp

osite

Co

rko

ak

99

Impregnation of Textiles

• Impregnation of textiles with furan resin

Production of prepregs

• Excess resin is squeezed out in the sqeeze rollers

• Subsequent press process in order to produce finished parts

Naturfaservlies

Matrix

FoulardImprägniertes

Vlies

Trockner Produktionsrichtung

Naturfaservlies

Matrix

FoulardImprägniertes

Vlies

Trockner Produktionsrichtung

NF textile

Furan resin

Foulard

Dryer

Prepreg

1010

Compression Molding

• Natural fibers are

pressure sensitive (max. 60 bar)

temperature sensitive (degradation at 200 °C)

• Natural fiber composites always contain porosity

decreasing density and mechan. performance

• Furan resin cures by a

polycondensation reaction

steam occurs

MatrixMatrix porosity

Lumen

Impregnation

porosity

Interface

porosityFiber

1111

Compression Molding

Optimization of compression molding process in order to increase

the density and reduce porosity content in the composite

repeated opening of the mold to

release the steam

Isochoric pressing with distance plates

for defining the end volume

higher density

of composites

1212

Continuous Compression Molding

• Production of almost endless panels, sandwiches, and profiles

using the CCMM

• Works on the basis of a semi-continuous process with alternating

press and transport stages

Unwinding stations

Press assembly

Material feed unit

Flax/furan

prepregCork roll Endless Profile

1313

Other Processing Methods

Vacuum infusion

• Resin mixing, cutting of

textiles, infusion, sectioning

and cutting

• Resin cures at RT (48 h)

Pultrusion

• Fiber reinforcement is

saturated with a resin and

pulled through a heated die

• Requirements for the resin are

high pot life, low viscosity, high

reactivity, and low amount of

volatiles

1414

Results - Natural Fiber Composites

• Tensile modulus of flax/jute-

furan composites much higher

than of standard NF materials

• Lower natural fiber weight

content

• Mechanical performance of NF

composites depends on density

Improving the mechanical performance of natural fiber

composites by using aligned fibers and optimizing the

manufacturing process (increasing the density)

Standard NF/PP Standard NF/DP Flax / furan Jute / furan0

2000

4000

6000

8000

10000

approx.

50 % NF36 % NF47 % NF

approx.

65 % NF

Tensile Properties

Yo

un

g's

Mo

du

lus [M

Pa

]

ρ = 0.8 – 0.85 g/cm³ ρ = 1.3 g/cm³

Flax/jute furan composite

1515

Results - Cork Sandwiches

• Combination of high performance NF composites with cork core

Improving the effective bending stiffness

Increase of Charpy impact resistance

• Correlation of performance to cork thickness

5 mm cork

(dried)5 mm cork

6 mm cork

10 mm cork

No cork0

1000

2000

3000

4000

Eff

ective

be

nd

ing

stiff

ne

ss [

kN

mm

²]

1 - 5 m

m

2 - 5m

m

3 - 5m

m

4 - 5 m

m

5 - 6 m

m

6 - 6 m

m

7 - 10 m

m

8 - 10 m

m

R - 0 m

m0

2

4

6

8

10

12

14

16

dried

no

cork

10 mm cork6 mm cork

Ch

arp

y I

mp

act

Re

sis

tan

ce

[kJ/m

²]

5 mm cork

dried

Flax furan cork composite

1616

Summary

• Standard applications of natural fibers in Europe in the automotive

industry for semi-structural components

• For the application as structural parts mechanical performance must

be increased

• Increase of mechanical properties due to aligned fibers (textiles) and

optimization of the manufacturing process (high density)

• Increase of bending behavior and Charpy impact resistance due to

the use of cork composite as sandwich core material

1717

Thank you for your attention

Acknowledgement

The research leading to these results has received funding from the

European Community’s Seventh Framework Programme

(FP7/2007 - 2013), under grant agreement Nº 285689.

Contact:

Dipl.-Ing. Jovana Džalto

Institut für Verbundwerkstoffe GmbH

67663 Kaiserslautern, Germany

Tel.: +49 (0)631 2017-437

E-Mail: [email protected]

Documents

IIG – Manufacturing with Biocomposites