Manufacturing with Biocomposites

Manufacturing with
Biocomposites
Jovana Džalto
Institut für Verbundwerkstoffe, Germany
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Content
• Who is IVW?
• Standard Applications for Natural Fiber
Composites
• Main Challenge – Mechanical Performance
• BioBuild Materials
• Manufacturing Methods
• Results
• Summary
2
Who is IVW?
Cooperationcontract with TU
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
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 superhydrophobic 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
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Standard Applications for
Natural Fiber Composites
• Since decades common use in the automotive industry for semistructural components
• Door panels
• Backrests
• Roof stiffenings
Source: Global Hemp
• New application fields
Mercedes E-Class
• Usage of „Green Composites“
Mercedes C-Class
Source: warwick.ac.uk
• Sports
• Furniture
• Ship building
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Standard Manufacturing Process
•
Fibers are almost randomly distributed in the non-woven
Fiber web
NF-mats
Fibers
Needling
Mat compaction
Carding line
•
Cross lapping
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
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Main Challenge –
Mechanical Performance
Influence of fiber orientation in reinforcing textiles
Stiffness
Strength
Multi-directional
natural fiber textile
Bi-directional
natural fiber textile
Uni-directional
natural fiber textile
Fiber weight fraction [%]
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Main Challenge –
Mechanical Performance
Influence of density on E-Modulus
E-Modulus [MPa]
6000
5000
Standard
NF/PP material
for automotive
applications
4000
3000
2000
1000
0
0,75
0,8
0,85
0,9
0,95
1
1,05
Density [g/cm³]
Low compression
 low density
 high porosity
High compression
 high density
 low porosity
Same natural fiber material
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BioBuild Materials
Increasing the mechanical performance by using aligned fibers
Jute
Flax
•
Bast fiber bundles
•
Natural fiber textile
Use of furan resin as an agricultural waste product from the sugar
industry
Use of leftovers from the cork stoppers manufacturing
Cork
composite
 cork composites
Cork oak
•
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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
Dryer
Trockner Produktionsrichtung
NF textile
Naturfaservlies
Foulard
FoulardImprägniertes
Prepreg
Vlies
Furan resin
Matrix
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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
Matrix
Matrix porosity
Lumen
 steam occurs
Interface
porosity
Fiber
Impregnation
porosity
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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
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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
Cork roll
Flax/furan
prepreg
Material feed unit
Endless Profile
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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
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Results - Natural Fiber Composites
Tensile Properties
Tensile modulus of flax/jutefuran composites much higher
than of standard NF materials
•
Lower natural fiber weight
content
•
10000
Young's Modulus [MPa]
•
8000
6000
Flax/jute furan composite
4000
2000
Mechanical performance of NF
composites depends on density
0
Standard NF/PP
Standard NF/DP
Flax / furan
Jute / furan
approx.
50 % NF
approx.
65 % NF
47 % NF
36 % NF
ρ = 0.8 – 0.85 g/cm³
ρ = 1.3 g/cm³
Improving the mechanical performance of natural fiber
composites by using aligned fibers and optimizing the
manufacturing process (increasing the density)
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Results - Cork Sandwiches
•
Combination of high performance NF composites with cork core
 Improving the effective bending stiffness
Flax furan cork composite
 Increase of Charpy impact resistance
Correlation of performance to cork thickness
Charpy Impact Resistance [kJ/m²]
Effective bending stiffness [kNmm²]
•
4000
3000
2000
1000
0
ork
m c d)
5 m (drie
m
5m
k
cor
m
6m
k
cor
mm
10
k
cor
No
k
cor
5 mm cork
16
6 mm cork
10 mm cork
no
cork
14
12
10
8
6
4
2
0
1-
dried
m
5m
2-
m
5m
dried
3-
m
5m
4-
m
5m
5-
m
6m
6-
m
6m
mm
mm
mm
10
10
-0
R
7
8
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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
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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]
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