Recent Developments in HighPerformance Thermoplastic
Composites
Allan Murray, Ecoplexus Inc.
Klaus Gleich, Southern Research Institute
ACCE 2003
Overview
• Introduction
• Materials
• Process Technology
• Applications
Why Use Composite Materials ?
Specfic Tensile Properties of Polymer Matrix Composites
4.5
4
Continuous Unidirectional Carbon
Composites
3
Glass & Carbon
LFT & Continuous
Other Fibers
Varying Fiber Orientations
8
Specific Modulus (x10 in.)
3.5
2.5
2
1.5
LFT Carbon
Composites
Metals
1
0.5
Plastics
Continuous Uni-directional
Glass Composites
LFT Glass
Composites
0
0
1
2
3
Specific Strength (x106 in.)
4
5
6
Thermoplastic Composites
Benefits
Unique properties
Vibration dampening
Light weight
Potential for low cost
Shelf life
Recyclable
Durability
Fatigue
Corrosion
Toughness
Limitations
Cost
Materials
Manufacturing
Tooling
Design know-how
Manufacturing knowhow
Use temperature
Thermoplastic Composites
Many Polymer Options
Polyethylenes
Polypropylenes
Nylons
Polycarbonates
Acrylics
Polyesters
Polyimides
Polysulfones
Polyketones
Polyurethanes
the list continues
Many Property Options
ultimate strain > 100%
no microcracking
no delamination
dampening
no water uptake
low dielectric properties
melt formable
weldable
elastomeric - plastic - elastic
behavior
the list continues
Cost Challenge
Materials:
Carbon Fiber / Epoxy, Carbon
Fiber / BMI, Carbon Fiber /
PEEK
Processes:
Hand Lay Up
Costs in $/lb
Typical Aerospace Structure
$50 - $100/lb
and more
Apply Materials and
Processing Techniques
being Developed for
Automotive Applications to
Aerospace Applications
Innovative Materials and
Processes
$5 - $20/lb
Automotive Structures
$1 - $3/lb
Materials:
Thermoplastic Woven Sheets, Glass,
Carbon and Kevlar Fiber, Engineering
Polymers
Processes:
Co-Compression Molding, CoInjection Molding, Thermoforming
Materials:
Glass Fiber / Polypropylene, SMC/BMC
Processes:
Compression Molding, Injection Molding
High-Performance Thermoplastic
Composites
• Properties are fiber dominated
• Oriented long or continuous fiber reinforcement
• High volume fiber fraction (up to 65% by volume)
Key benefits:
• Reducing thermal limitations (e.g. creep) caused by the TP
matrix system
• Reducing costs and weight and retaining toughness,
formability, weldability, short cycle times, recyclability
benefits of the thermoplastic matrix
Thermoplastic Materials
Commercial Materials
• GMT (Glass Mat Reinforced Thermoplastics)
• Pultruded Products
– LFT (Long Fiber Reinforced Thermoplastics)
– CFT (Continuous Fiber Reinforced Thermopastics)
•
•
•
•
•
Wire coated products
Commingled fibers
Powder coated materials
Film sticking
Slurry processes
Long-Fiber
Thermoplastic Composites
•New Hot-melt Process
Produces Fully Wet-out
Composite Products
•Wide Range of Polymers
and Fibers
•Continuous Tape and
Rod Products
•Discontinuous Products
with Any Fiber Length
•Glass Products <$1.00/lb
•Carbon Products
<$8.00/lb
Pilot Production for
Thermoplastic Composites
Short Fiber, Long Fiber and
Continuous Fiber Composites
Typical short fiber
thermoplastic
material,
granules with fiber
length of approx. 2
to 4 mm,
resulting fiber length
in a part of approx.
0.4 mm
Long fiber
thermoplastic material,
pellets of ½” and 1 “
fiber length, resulting
fiber length in a part of
approx. 4-6 mm in
injection molding and
approx. 20 mm in
compression molding
Continuous
reinforced
thermoplastic
material, tape used
for woven sheets
(thermoforming),
filament winding
or pultrusion
Typical Pultruded Prepregs
• Fiber:
– E-glass, S-glass, Carbon, Aramid, polymer fibers
• Matrix:
– PE, PP, PA (6, 6/66, 12, …), PET, PBT, PC, PEI, PPS,
SMA, blends, …
• Fiber content:
– 20% - 60% standard, some up to 84%
• Product forms:
– Tape, pellets (0.5”, 1”), woven tapes
– more complex textile structures in development
Twintex - The Commingling Concept
Consolidated
Composite
Twintex®
Prepreg
Temperature
+ Pressure
Source: Vetrotex
Twintex – The Commingling
Concept
E Glass
adapted sizing
Plastic filament
Additives :
- coupling agent
- UV stabilizer
- natural or black
Source: Vetrotex
Twintex – The Manufacturing
Process
Extruder
Bushing
Glass
TP
Commingling
Roving
Source: Vetrotex
Twintex - Commingled Fiber Products
Specfic Tensile Properties of Polymer Matrix Composites
• Fiber/matrix
combinations:
– E-glass/PP, E-glass/PET
4.5
4
Continuous Uni-directional
Carbon Composites
3.5
3
Glass & Carbon
LFT & Continuous
Other Fibers
Varying Fiber Orientations
2.5
• Fiber content:
– 60 % and 75 % by weight
• Product forms:
– Roving, fabric, pellets
Twintex
2
1.5
LFT Carbon
Composites
Metals
1
0.5
Plastics
Continuous Uni-directional Glass
Composites
Twintex
LFT Glass
Composites
0
0
1
2
3
4
• Limitations:
– Matrix material must be usable for a fiber spinning process
 limitations in MFI/viscosity, additive type and additive
content
5
6
Physical Property Data
Vetrotex Twintex
Matrix
Reinforcement
wt.% reinforcement
Orientation
Density g/cm3
Tensile Strength MPa
Tensile Modulus GPa
Flexural Strength MPa
Flexural Modulus GPa
Flexural Elongation %
Compression Strength MPa
Shear Strength MPa
Impact CHARPY un-notched kJ/m2
J/cm3
Heat deflection temp. (1.82 MPa) oC
Specific Tensile Modulus (x10^8in)
Specific Tensile Strength (x10^6in)
PP
glass
60
1/1
1.5
350
15
280
13
2.5
140
22.5
220
8
159
0.4
0.9
PP
glass
60
4/1
1.5
500/180
24/8
380/160
18/6.1
2.5/3.6
230/100
24/15
330/90
11/3
159
0.6
1.3
Source: Saint-Gobain Vetrotex, “Twintex PP and PET Mechanical Properties (non standard)”
PP
glass
75
1/1
1.75
420
21
340
17.5
2.5
160
22.5
300
10
159
0.5
1.0
PP
glass
75
UD
1.75
700
38
400
32
2
170
22.5
445
15
159
0.9
1.6
PET
glass
65
1/1
1.95
440
25
600
22.5
3.25
410
43
300
10
257
0.5
0.9
Powder Impregnated Prepregs –
The Hexcel TowFlex-Technology
Fiber Creel
Racks
Fluidized Bed
Powder Coating
Chamber
IR Oven
Puller
Take-up
System
To Weaving
To Tapes
To Pellets
Charged Resin
Powder
Source: Hexcel
Hexcel TowFlex
Specfic Tensile Properties of Polymer Matrix Composites
4.5
• Typical fibers:
• Typical resins:
– PP, PA6, PPS, PEI,
PEEK
• Typical product forms:
–
–
–
–
Flexible Towpreg
Woven fabric
Braided Sleeving
Unidirectional Tape
Continuous Unidirectional Carbon
Composites
Glass Carbon
3.5
Specific Modulus (x108 in.)
– Carbon, E-glass, Sglass
TowFlex
4
3
Glass & Carbon
LFT & Continuous
Other Fibers
`
Varying Fiber Orientations
Carbon Towflex
2.5
2
1.5
LFT Carbon
Composites
Metals
1
0.5
Plastics
Glass Towflex
Continuous Uni-directional
Glass Composites
LFT Glass
Composites
0
0
1
2
3
4
6
Specific Strength (x10 in.)
5
6
Physical Property Data
Hexcel Towflex
Material
Resin Content
(weight %)
Fiber volume
(volume %)
Composite density
(g/cc)
Flexural Strength
D790 (MPa)
Flexural Modulus
D790 (Gpa)
Tensile Strength
D3039 (MPa)
Tensile Modulus
D3039 (26 Gpa)
Compression
Strength D695
(MPa)
Compression
Modulus D695
(Gpa)
Specific Tensile
Modulus (x10^8in)
Specific Tensile
Strength (x10^6in)
TF-CN6100
TF-CPP100
TFF-CN6- TFT-CN6100
100
TFF-CPP- TFT-CPP100
101
TFFTF-EGN6- TFF-EGN6- TFT-EGN6- TF-CPPS- TFF-CPPS- TFT-CPPS- TF-EGPP- TFFTFT-EGPP- EGPPS100
100
100
103
103
103
101
EGPP-100 100
101
38
38
38
38
38
38
34
34
34
43
43
43
30
30
30
35
51
45
51
51
45
45
46
46
46
51
51
51
46
46
46
51
1.45
1.31
1.45
1.45
1.31
1.31
1.77
1.77
1.77
1.59
1.59
1.59
1.64
1.64
1.64
1.96
1517
627
827
1517
524
627
1034
517
1034
1724
869
1724
600
386
600
531
107
104
55
107
51
104
34
19
34
114
58
114
32
17
32
27
1655
821
1655
655
869
352
869
1655
869
1655
290
385
116
66
116
59
38
22
38
110
64
110
18
24
945
579
441
945
172
579
634
372
634
1055
448
1055
558
248
558
379
110
110
58
110
49
110
34
26
34
112
63
112
37
21
37
31
3.2
1.8
3.2
1.8
0.9
0.5
0.9
2.8
1.6
2.8
0.4
0.5
4.6
2.3
4.6
2.0
2.0
0.8
2.0
4.2
2.2
4.2
0.7
0.8
Source: Hexcel Composites (March 2003)
www.Hexcel.com
Process Technology
Current Composite Materials and
Processes
Process
Injection Molding
Type of Application
Low-Structural
Components
Compression
Molding
Semi-Structural
Components
Thermoforming
Hand Lay Up /
Vacuum Bag /
Autoclave
Structural Components
Composite Performance versus
Fiber Length
1.2
Fillers Short Fiber
Long Fiber Continuous
Relative Property Level
1.0
0.8
Modulus
Strength
Impact
Processibility
0.6
0.4
0.2
0.0
0.1
1
Length (mm)
10
100
Source: OCF
The Long Fiber Advantage
• Stress is transferred to the
fibers - the structural
members of the composite
• Long fibers create a
“skeletal structure” within
the molded article that
resist distortion and
provide unmatched
strength, toughness, and
overall performance
Source: Ticona
Continuous Fiber Advantage
• In continuous oriented fibers the load is
ultimately ‘fully’ transferred to the fiber
• As a result tensile creep is limited in fiber
direction
Manufacturing Processes for HighPerformance TP-Composites
• Low volume manufacturing processes
– Discontinuous processes
•
•
•
•
•
Thermoforming
Thermoplastic S-RIM, RTM and VARTM
Thermoplastic filament winding
Vacuum bag molding
Net shape preforming (modified P4)
Manufacturing Processes for HighPerformance TP-Composites
• High volume manufacturing processes
– Discontinuous processes
• Injection molding with
– LFT-pellets and concentrates (high performance resin/fiber combinations)
– Inline compounding (high performance resin/fiber combinations)
– Back molding / local reinforcement
• Compression molding
– LFT-pellets and concentrates (high performance resin/fiber combinations)
– Inline compounding (high performance resin/fiber combinations)
– Back molding / local reinforcement
• Stamp forming
–
–
–
–
Preheated preforms
Matched metal tools
Potential to manufacture very thin sections (0.5 to 1 mm)
Drapable material required
– Continuous processes
• Pultrusion
• LFT-extrusion
Materials Used For Liquid Molding
Processes
Materials used for liquid molding processes
– Cyclics
– Reactive nylon
– Fulcrum
• Requirement for these materials
– Viscosity less than 3000 mPa.s (cP) (better less
than 1000 mPa.s (cP))
Cyclics
•
•
•
•
•
Cyclic form of PBT, PET, PC and others
Only PBT commercial available
Based on a ring shaped cyclical form
One or two part systems
Solid at room temperature – low viscosity resin at
elevated temperature (approx. 150 cP)
• Polymerize into the Polymer using a catalyst
• Isothermal process
• Typical process temperature: 180 – 200 oC
Reactive Nylon
For more information see presentation on
“Reactive Thermoplastic
VARTM/RTM/S-RIM”
Fulcrum
• ISOPLAST matrix (Dow proprietary engineering
thermoplastic polyurethane)
– Thermoplastic viscosity issues addressed by ability to
reverse polymerization in the melt stage, reducing
viscosity to ensure good impregnation
– Repolymerizes upon cooling, retaining traditional
thermoplastic composite advantages
• High impact resistance
• Recyclability
• High elongation to failure (~2.5%, versus ~1-1.5% for
thermosets)
• Zero-emissions processing
• Fulcrum is the combination of ISOPLAST and
pultrusion, with specific hardware design
• Provides 10-fold line speed improvement over
typical thermoset pultrusion lines
• Allows thermoforming, welding, and overmolding of
finished pieces
Thermoformed Fulcrum Components
Figures from “Fulcrum Thermoplastic Technology; Making High-Performance Composite via Thermoplastic Pultrusion” Dow Plastics, January 2000
Physical Property Data
Dow Fulcrum
Matrix
Reinforcement
v.% reinforcement
Density g/cm3
Tensile Strength MPa
Tensile Modulus GPa
Elongation at Break %
Flexural Strength MPa
Flexural Modulus GPa
Longitudinal Flexural Strength MPa
Longitudinal Flexural Modulus GPa
Transverse Flexural Strength (MPa)
Compressive Strength
Compressive Modulus
Specific Tensile Modulus (x10^8in)
Specific Tensile Strength (x10^6in)
Polyurethane Polyurethane Polyurethane Polyurethane
glass
glass
glass
glass
76.6 (wt.)
45
55
66 (wt.)
1.91
1.74
1000
980
45
43
2.5
1.5
1150
1050
48
40
1080
1340
35
44
151
122
151
790
430
440
46
35
35
0.9
2.1
45v.% and 55v.% data from Matweb.com
76.6wt.% and 66wt.% data from “FULCRUM: Thermoplastic Composite Technology, Making High-performance Composite via Thermoplastic Pultrusion” Dow
Plastics, January 2000
Reactive Thermoplastic
VARTM/RTM/S-RIM
• Similar the thermoset process
• Reaction of at least two components creates a
thermoplastic resin that can be melted, preshaped, welded, …
• Low viscosity is required
• Possible materials: Nylon, TPU, C-PBT
(Cyclics)
Problems Connected With
Thermoplastic RTM
• Reaction can be stopped or made incomplete by
– Moisture
– Chemicals in fiber sizing
• Most of the thermoplastic compatible sizings are not developed for
such type of processes
• Availability of compatible sizings in form of fabric is very limited
– Oxygen
• Only limited support of material manufacturers
• Material costs (in case of c-PBT)
Thermoforming
Heat in Oven
Thermoforming
Operation
Finished
Product
Thermoforming
• Weight performance:
– Good weight/performance ratio for fabric reinforced sheets due to
continuous fibers
– Reduced weight/performance ratio for extruded sheets depending on
the resulting fiber length
• Design flexibility:
– Limited, especially for complex geometries
– Simulation tools available
• Processability:
– Stabilization against oxidation necessary
– Fiber disalignments with continuous fibers possible depending on
geometry, material, tooling and process conditions
• Recyclability:
– High rate of production scrap (fixation)
– No direct recyclability
– Use in other processes like plastication of regranulation
TP S-RIM, RTM, VARTM
• Weight/performance:
– Excellent
• Design flexibility:
– Limited to preforming capability, flow length and flow
behavior of the resin
• Processability:
– Reaction can be sensitive to moisture and fiber sizing
• Recyclability:
– Production scrap due to preforming step depending on
preforming method
– No direct recyclability; can be used in other processes
TP Filament Winding
• Weight/performance:
– Excellent
• Design flexibility:
– Limited to symmetric parts that can be wound on a mandrel
• Processability:
– Higher oxidative stabilization required
• Recyclability:
– Low rate of production scrap
– No direct recyclability
– Scrap can be used in other processes
Vaccum Bag/ Hand Lay-Up
• Weight/performance
– Excellent due to continuous fiber reinforcement
• Design flexibility
– Limited to drapability and to the posibility of manually lay up
• Processability
– Higher void content due to low pressure consolidation
– Using autoclave to reduce void content
– Often fiber disalignments
• Recyclability
– High rate of production scrap possible depending on the size of the
material sheets and the part geometry
– No direct recyclability
– Scrap can be reused in other processes
LFT-Injection Molding
• Weight/Performance
– Lower end of thermoplastic composites due to reduced fiber length in
the final part
– Improvements possible by using local reinforcements (using pultruded
sections, sheets or tapes of continuous composites  localized
strengthening and stiffening, reduction of warpage)
• Design Flexibility
– High
– Flow channels and positions of gates have to be carefully designed
• Processability
– Highly stable
• Recyclability
– Low production scrap rate
– Can be reused in the same process
Compression Molding
• Weight/Performance
– Medium
– Retaining fiber length gives excellent properties for a random oriented
material, but is lower than using a fabric
– Local reinforcement or fabric reinforced GMT improve it (using
pultruded sections, sheets or tapes of continuous composites 
localized strengthening and stiffening, reduction of warpage)
• Design flexibility
– High
– Special simulation tools available
• Processability
– Very stable process
• Recyclability
– Some production scrap due to trim operations
– Scrap can be added and reused in the same process (GMT only sheets
can be reused in the same process, but not recommended)
Curv
• Self-reinforced polypropylene
• Consists of “hot compacted” polypropylene fiber or tape
– Surface of tape or fiber melts during compaction to form the “matrix”
that binds the directional elements together
• Oriented morphology provides over six-fold increase in tensile
strength and nearly 5-fold increase in tensile modulus over
isotropic polypropylene, with ~2% weight penalty
• Nearly doubles tensile strength of 40% random mat short glass
polypropylene, with comparable modulus and 22% weight
savings
• Elimination of glass reinforcement has several advantages:
–
–
–
–
–
Increased recyclability
Reduced weight
Lower temperatures and pressures for thermoforming
Reduced irritation in the workplace
High strain to failure, with good impact strength
Data from “A New Self-Reinforced Polypropylene Composite” Jones, Renita S. and Derek E. Riley
Physical Property Data
Curv
Density g/cm3
Tensile Modulus GPa
Tensile Strength MPa
Heat deflection temperature oC
Notched Izod impact J/m
455 KPa
1820 KPa
+20oC
-40oC
Thermal expansion / oC x 10-6
Specific Tensile Modulus (x10^8in)
Specific Tensile Strength (x10^6in)
from BP document “A New Self-Reinforced Polypropylene Composite” Jones, Renita S. and Derek E. Riley, 2002
0.92
5
180
160
102
4750
7500
41
0.2
0.8
Pultrusion
• Weight/performance
– Good to excellent due to continuous reinforcement
• Design flexibility
– Low design flexibility
– Limited to constant cross sections, but can be shaped
(pull/press)
• Processability
– Only limited experience available
– Depends on stabilization of the material as well as used
material form
• Recyclability
– Low rate of production scrap expected
– No direct recyclability
– Can be used in other processes
LFT-Extrusion
• Weight/performance
– Medium weight performance
– Depends on retaining fiber length
• Design flexibility
– Low design flexibility
– Limited to constant cross sections
– Can be post shaped or pull formed
• Processability
– Not a lot of experience
– A stable process is expected using the right die design
• Recyclability
– Low rate of production scrap
– Can be reused in the same process
Economics
Process
Cycle Time
Tooling Costs
Scrap Rate
Overall Economics
Thermoforming
Medium
Low
High
Good for low volume production
with no or limited thickness variation
TP S-RIM, RTM,
VARTM
Medium to long, up to several
minutes
VARTM: low,
single sited tool
RTM: low to
medium
S-RIM: Medium
Depends on
preforming
technique;
often high for
complex
shaped parts
Good for low volume production
TP Filament Winding
Medium to long, depending on
number of tapes and heating system
Low to medium
Low
Good for symmetrical parts in low to
medium volume production
Vacuum Bag/
Hand Lay-up
Long; manual preparation can be
hours for a part
Low, single sided
tool
Medium to
high
Good for prototyping. Not
recommended for production scale.
Injection Molding
-LFT
-ILC
Short cycle times; typically 50 – 80
sec.
High; steel tools
with ejector pins
and slides
Very low
Excellent for high volume
production
Compression Molding
-GMT
-LFT
-ILC
Short cycle times; typically 35 – 60
sec.
High; steel tools
with ejector pins
and slides
Low – medium
depends on cut
outs. Scrap can
be reused
Excellent for high volume
production of large components
Pultrusion
Continuous process; not enough
experience on throughput
Medium
Low
Limited experience available
Extrusion
Continuous process; throughput
mainly limited by cooling capacity
of calibration die
Medium to high
Low
Expected to be cost
effective for profiles
Applications
Applications For High-Performance
Thermoplastic Composites
• Aerospace and defense:
– Radomes, wing and fuselage sextions, anti-ballistics
• Infrastructure and Construction
– Window profiles, rebar, beams, structures, composite bolts
• Consumer / recreational
– Orthotics, safety shoes, sporting goods, helmets, personal injury
protextion, speaker cones, enclosures, bed suspension slats
• Auto and truck
– Bumper beams, skid plates, load floor, seat structures
• Transportation
– Railcar structure, body structure and closures
• Energy production and storage
– Oil and gas structura tube, wind turbines
BMW M3 Bumper Beam
- Beam and crush columns
manufactured using
Hexcel TowFlex PA6
- Parts welded by high
frequency vibrational
welding
- 2 versions:
Source: Jacob Kunststofftechnik GmbH & Co. KG
www.jacob-kunststofftechnik.de
Standard M3 based on glass
fiber reinforcement
(approx. 40 cars / day)
M3 CSL (limited to 1600
total) using Carbon fiber
reinforcement
Helmets
Military helmet for Norwegian Army
Made by Cato Composites
50,000/year
TEPEX antiballistic 302
Aramid/PA6
continuous reinforcement
Source: Bond-Laminates GmbH
www.bond-laminates.com
White water helmet
Made by Prijon
TEPEX dynalite 701
Glas, Carbon, Aramid/PA6.6
Continuous reinforcement
Source: Bond-Laminates GmbH
www.bond-laminates.com
Aircraft Applications
Fixed wing leading edge for Airbus
Fokker Special Products/Airbus
TEPEX semipreg 107
Non fully consolidated, flexible layers
of continuous fiber reinforced thermoplastics
Glass/PPS
Wing access panel for Airbus
Fokker Special Products/Airbus
TEPEX semipreg 207
Non fully consolidated, flexible layers
of continuous fiber reinforced thermoplastics
Carbon/PPS
Mine Sweeper Armouring
•Made from TEPEX
antiballistic 302
•Aramid/PA6
•Continuous reinforced
•Made by Kvaerner
Source: Bond-Laminates GmbH
www.bond-laminates.com
Safety Shoes
• Composite Toecap
– History:
• Composite Toecaps were manufactured in the past using GMT with
50% fiber glass content
• Changing the regulations, this was not sufficient to meet the 200 J
requirement
– Newer development:
•
•
•
•
65 g / piece (metal 105 g /piece)
200 J resistance
Made from Twintex and LFT, 60% fiber glass, PP
Manufactured by Security Composites Ltd. (UK)
Others
• GF/PP composite tank Produced by Covess (Belgium) using
Twintex and GMT, welded out of 3 pieces and designed to
withstand pressure to 100 bar
• Evaluation of thermoplastic composite rebars made with the
Fulcrum process
• Thermoplastic composite bolts made by Clickbond Inc. using a
thermoforming approach
• Loudspeaker cones, electronic housings and lightweight
carbon fiber reinforced structural applications for the
automotive industry made by Centrotec AG
• Prototype of a continuous fiber reinforced PP boat (JEC 2000
Innovation Award) made from Twintex using vaccum bag
molding. Developed by Halmatic, Ltd.
• Golf club shafts made from PPS/carbon prepreg tape with 66 –
68% fiber content. Multi-step operation including a table
rolling, a compression and an oven consolidating step.
Manufactured by Phoenixx TPC.
The Future of Thermoplastic
Composites
• Will go to more structural applications using
different technical thermoplastics in
combination with glass, carbon and synthetic
fibers.
• Will replace metal applications and reduce
weight.
• Improved processing methods will be
developed and applied.
Conclusions
• High-performance thermoplastic composites
with fiber-dominated properties are a way to
–
–
–
–
lower cost
higher performance
short cycle times
Recyclability
• Pre-impregnation can improve wet out and
performance over commingled prepregs
• Materials and manufacturing methods are
available
Acknowledgements
• Aaron Brice and Erik Nolte, Stewart
Automotive Research, LLC