Carla L. Lake, PhD Applied Sciences Inc 141 W. Xenia Ave Cedarville, Ohio

Carbon Nanofiber Composites: From Innovative R&D to Commercial Reality

Applied Sciences, Inc. Outline

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• Carbon / Nano carbon

• Carbon Nanofibers

• Carbon Nanofibers vs. Carbon Nanotubes

• Applications

• Anode Material for Li-ion Batteries

• Multi-Functional CNF Reinforced Polymers Composites

• Dispersion of CNF / Dispersion Analysis

• Environmental, Health and Safety

Applied Sciences, Inc. Nano Carbon Carbon Nanotubes Carbon Nanofibers

Fullerenes

Nano graphene

Pyrograf-III Carbon Fiber

CNF Nested Conic Morphology

is Unique

Carbon Nanofibers (CNF)

Trade name: Pyrograf-III.

Diameter: ~ 50-200 nanometers

Provides electrical, structural, and thermal/ ablative properties.

Current status: Pilot scale production, intermediate cost.

Uses: Conductive polymers, EMI shielding, lightning protection, structural enhancement, ablatives.

Potential market: >1500 TpY

Applied Sciences, Inc.

Carbon nanofibers (CNF) are a unique form of vapor-grown carbon fiber that bridges the gap in physical properties between larger, conventional PAN or pitch-based carbon fibers (5 –10 µm) and smaller single-wall and multi-wall carbon nanotubes (1 – 10 nm)

Carbon Nanofibers

Applied Sciences, Inc.

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CNF vs CNT

Exposed edges along the fiber

Benefits of using CNF over CNT

MWCNT CNF

Easier to disperse Easier to process Easier to functionalize Simultaneous provides electrical and mechanical property enhancements Lower overall cost of use

Applied Sciences, Inc. Carbon Nanofibers

Diameter: 70 – 150 nm

Length: > 50 μm

Electrical conductivity1,2 : 1x10-3 - 1x10-4 Ohm.cm

PS LHT

Heat treatment Temperature/ Surface energy/Conductivity 1 M. Endo et al. Carbon 39, p1287, 2001

2www.pyrografproducts.com 3Ozkan et al. Carbon 48, p239, 2010

Structural and transport properties:

HHT

Tensile strength1,3 :2.90 – 2.35 GPa

Surface energy2: 133 – 275 mJ/m2

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Applied Sciences, Inc. CNF Product forms

Powder • Diameter • Length • Surface properties Sheet • CNF mat • 100 % CNF paper Dispersions • Thermoset • Thermoplastic masterbatches • Tapes • Thin films • Nanofluids

Applied Sciences, Inc. Applications

Defense Sporting and electronic goods

Automotive

TRL 9

TRL 7

TRL 6

TRL 5

TRL 4

TRL 3

TRL 2

TRL 1

TRL 8

Sporting Goods Audio Equipment

Li-ion batteries ESD Carpets/Fabrics Electronic Device Shielding Fire Retardant Foam Automotive Panels

Thermally Conductive Grease ESD Components Conductive thin films

Aerospace Structural Components

Biosensors/Smart Composites

Solar Cells Biomedical Applications

Continuous Filaments For Non-metallic Cable & Wiring Space Elevator

Conductive Thin Films Multi-functional/Structural Composites

Carbon Nanofiber Applications Technical Readiness Level

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Anti-Corrosion/Erosion Coatings Conductive Inks

High Capacity, High Power Anode Materials for Energy Storage

Applied Sciences, Inc.

Wang C.M. et al. Nano Letters 2012

Anode Materials for Li-ion Batteries

Automotive

Applied Sciences, Inc. Anode Materials for Li-ion Batteries

Defense

Applied Sciences, Inc.

Four Times Greater Charge Capacity for Silicon Coated Carbon Nanofiber Anode (C-Si) compared to graphite (LiC6)

MN8277, Charge-Discharge efficiency of C-Si

0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Cycle number

Cap

acit

y (m

Ah/

g)/1

00

LiC6

C-Si

Anode Materials for Li-ion Batteries

Applied Sciences, Inc.

These images clearly show that the silicon has expanded but is still chemically bonded, and electrically connected, to the CNF after 100 charging/discharging events.

TEM image of CNF coated with a thin layer of silicon prior to electrochemical cycling.

TEM image of silicon coating after 100 electrochemical cycles.

Anode Materials for Li-ion Batteries

Multi-Functional CNF Reinforced Polymer Composites

Applied Sciences, Inc.

Functional and morphological merits of CNFs for polymeric applications:

Advantages of Carbon Nanofibers

High aspect ratio (l/d) – 100 – 1000

Thermal conductivity up to 5 x copper

Electrical conductivity overlaps metals

Multi-functionality

Easier to disperse than CNTs1

Higher chemical reactivity

Recyclability

Reduced linear thermal expansion – dimension stability

Available in high volumes at a competitive price

High quality

1 M.Nyden,Polymer, 49: p. 635, (2008).

Applied Sciences, Inc.

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CNF LOADING

Electrostatic painting

automobiles

104 -106 Ω-cm

EMI/RF Shielding

< 10 Ω.cm

Lightning strike

protection

Antistatic

clean rooms, fuel lines

> 106 Ω-cm

Tailorable Electrical Conductivity

Applied Sciences, Inc.

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Electrostatic painting

Van Hattum et al. in Plast., Rubber Compos.: Macromol. Eng., vol. 35, 6/7 (200 6)

Achieve electrostatic conductivity at low loading levels

Smooth surface finishes

No primer required

Online painting

Higher transfer efficiency

Environmental friendly

Benefits of using CNFs

Applied Sciences, Inc. ESD/Wear pulleys

Multifunctionality

Achieve ESD conductivity at low loading levels

3 wt% CNF translates into a 4 fold improvement on wear

Lower coefficient of friction

Reported 20% energy savings in conveyor systems

Benefits of using CNFs

Material: PP/CNF;Pa6/CNF;PEEK/CNF

From: Tribology of Polymeric Nanocomposites | Klaus Friedrich | Elsevier

Applied Sciences, Inc. Direct part manufacturing

Multifunctionality

Isotropy

Reduced filler loading

Achieve ESD conductivity at low loading levels

Mechanical reinforcement

Decreased energy density

Benefits of using CNFs

CNF have been identified as a strategic material to be used as reinforcements and electrical conductive additives in thermoplastic polymers for direct part manufacturing

Applied Sciences, Inc. Direct part manufacturing

L. Folgar. Laser sintering of nanocomposites DPM Workshop, Fairborn, OH, March 2011. R.D. Goodridge et al., Polymer Testing 30 (2011) 94–100 B.P. Rice, DPM Workshop, Fairborn, OH, March 2011

Voids = Loss of mechanicals in the Z direction

Fillers help with consolidation.

Applied Sciences, Inc. Challenges

CNF cohesion: geometry; surface chemistry and energy

Resin chemistry and viscosity

Highly dependent on processing conditions

Dispersion

At a nanoscale: Surface effects dominate and Van der Waals forces become important !

Applied Sciences, Inc. Challenges

Mixing conditions have the highest impact on the properties that rely on a network formation: electrical resistivity, thermal stability and on the melt flow properties of the nanocomposites.

0 1 2 3 4 510010110210310410510610710810910101011

Volu

me

resis

tivity

[Ohm

.cm

]

CNF loading [wt%]

Mixing energy/Deformation

Processing/Mixing

Applied Sciences, Inc.

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Solutions Understanding and monitoring DISPERSION of CNF is KEY to overcome these challenges and improve the fidelity of its nanocomposites!

Determine the effect of processing conditions (i.e. shear history, residence time, deformation) on the dispersion of CNF in polymeric resins.

Modeling the effect of CNF dispersion on properties like electrical conductivity and mechanical reinforcement .

Product solutions that supersede agglomeration tendency of nano carbons.

Applied Sciences, Inc.

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Product Solutions MASTERBATCHES 5 – 20 wt%

PP, HDPE, PS; PA6, PA12, PC; TPU PEEK, PEI, PEKK

NANOMAT

PRE-DISPERSIONS

EPOXY VINYL ESTHERS BMI

Carbon Nanomaterials Dispersion Analysis Method

Applied Sciences, Inc.

How can we monitor dispersion in nanocomposites?

Most methods used for assessing fiber dispersion are subjective, non-reproducible and

with a limited sampling area

50 µm

HDPE/ 5wt%CNF Masterbatches

Same filler, same loading

3 different dispersion levels 3 different processing conditions

3 different composites

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Klaus Friedrich

Applied Sciences, Inc.

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Dispersion vs Mixing Energy

Increase in dispersion with mixing energy

Applied Sciences, Inc.

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100 µm

2.5 lb/ft3 3.5 lb/ft3

4.5 lb/ft3 6.0 lb/ft3

Dispersion vs CNF Fiber Length

Applied Sciences, Inc.

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50

500

5000

0.1 1 10 100 1000

Var

ianc

e [-]

Length scale [µm]

2.5 lb/cu.ft

3.5 lb/cu.ft

4.5 lb/cu.ft

6.0 lb/cu.ft

Dispersion vs CNF Fiber Length Improved dispersion with shorter fibers

(up to 4.5lb/ft3)

Applied Sciences, Inc. Multi-scale image analysis (MSIA)

Quality control tool

Define processing conditions

Compare fiber types/grades

Compare fiber lengths

Compare between polymer matrices

Use:

Environmental Health and Safety

Applied Sciences, Inc.

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PPI’s Proactive Approach to EH&S

NIOSH is continually performing air quality assessments at PPI

NIOSH results assisted PPI in selecting appropriate PPE (see

MSDS) and safe manufacturing methods

When mutually agreed upon, PPI will ship CNF product in

containers that connect directly with customer’s on-site storage

container or processing equipment

Shipping containers will be returned to PPI and re-used

Applied Sciences, Inc.

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Consent Order Requirements

Imported or domestically manufactured nanomaterials used in commercial products must be listed under The Toxic Substances Control Act (TSCA) Section 8(e)

CO specifies personal protective equipment (PPE) for PPI workers and customers, recordkeeping, and specialized testing required for compliance

CO enables the use of all PPI’s CNF products to be included in domestic, commercial applications

CO covers all milled and non-milled PR-19 and PR-24 CNF types in all three grades (PS, LHT, HHT)

Applied Sciences, Inc.

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PPE Requirements

Respiratory Protection NIOSH certified air-purifying, tight-fitting full-face

respirator equipped with N-100, P-100, or R-100 filter with an APF of 50 or greater

Dermal Protection

gloves impervious to PMN substances full body clothing impervious to PMN

substances (demonstrated by ASTM F739) PPE should be used with appropriate engineering controls

Applied Sciences, Inc. Contact information

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Contact info:

Also visit: www.apsci.com www.pyrografproducts.com

Questions?

Dr. Carla Leer-Lake Applied Sciences Inc Ph: 937-766-2020 ext 134 cleer@apsci.com