Material Characterization of Natural Fiber – Acrylic ... · Material Characterization of Natural Fiber – Acrylic Thermoset Composites ... ASTM D638 -10 Flexural ... Material Characterization

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Material Characterization of Natural Fiber – Acrylic Thermoset Composites

Andre BendoJeremy Funk, John Norton, Dr. Gero Nordmann & Dr. Michael KalbeBASF Corporation

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Presentation Overview

Key Trends / Drivers

Chemistry Advantage

Target Composite Applications

Mechanical Performance Comparison

Summary

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Chemistry Advantage



Summary

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CAFE Standards requiring improved fuel efficiency

35.5 mpg by end of 2016

Proposed increase to 54.5 mpg by 2025

Strategies to meet rising standards

– Vehicle energy efficiency

– Power train / propulsion

– Weight reduction

Reducing vehicle weight allows for extended driving distances for alternative engines (electric or hybrid)

Interconnected

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Growing demand for environmentally – friendly materials

Interior air quality

– Emissions from resin & additives

– Reduction in VOCs

Green materials

– Bio-based resins (soy, corn)

– Natural fibers

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Chemistry Advantage



Summary

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Chemistry Advantage

Acrylic-based thermoset binder provides opportunity to

Produce very-durable composites & nonwovens

Lower weight at comparable performance or

Increase performance at same wall thickness

Reduce or eliminate VOCs, Odor & Fogging

Address rising demand for “green” materials

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OH

XOHHO

OHOOHO

OOH

OOH

Acrylic-based solutions consist of two components, dissolved in water

...and a polyalcohol:

...a polycarboxylic acid: ...to form a polyester

O

XO

O

O O

OO

O

O

X

X OX

Both components react at temperatures above > 130°C

Chemistry Advantage - Solutions

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OHOOHO

OOH

OOH

OH

XOHHO

Latex

...to form a latex-modified polyester

O

XO

O

O O

OO

O

O

X

X OX

Latex

Acrylic-based dispersions consist of two components, dissolved in water

...a polycarboxylic acid, modifiedwith a latex component:

...and a polyalcohol:

Both components react at temperatures above > 130°C

Chemistry Advantage - Dispersions

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Chemistry Advantage

Combines properties of thermoplastics & thermosets

Before cure: thermoplastic behavior

– Provides low-viscosity & excellent wetout of a wide variety of particles & fibers

– Allows production of prepregs / semi-finished goods

After drying & curing (at elevated temperatures): thermoset behavior

– Forms lightweight, durable thermoset

– Possesses excellent thermal, mechanical, & chemical stability

– Reduces VOCs, shelf-life storage issues

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Uncured resin (left) softens ≈50ºC;

Cure (right) occurs between 120-200ºC

DMA Analysis

Chemistry Advantage

acrylic resin dispersion withflexible-tough latex Tg ≈25ºC

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Chemistry Advantage

Production & curing of thermoplastic films

Can be applied to reinforcement / substrate via

– Impregnation (bath)

– Dipping

– Spraying

– Rolling

– Blow-Line

Bath

Foam

Spraying

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Chemistry Advantage



Summary

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Substrates Wood fibers Seed fibers: Cotton Bast fibers: jute, hemp, kenaf, flax...

Main application areas Automotive (ca 5 – 10 kg natural fibers are used in

each car)

Main products Door trims Rear window shelves Sound isolation parts Seat shells...

Characteristics of natural fiber composites

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15

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Chemistry Advantage



Summary

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Critical automotive interior specifications

Tensile properties – ASTM D638-10

Flexural properties – ASTM D790-10

Izod impact – ASTM D256-10

Water absorption (24 hrs)

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Constants

Mat type – 1000 gsm, kenaf (85%) / PET (15%)

Binder loading level ~28%

Chemistry Effect on Mechanical Properties

Dispersion grade vs. Solution grade vs. Dispersion/Solution Blend

Processing Parameters on Mechanical Properties

Cure Temperature

Cure Time

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Chemistry EffectMechanical Performance Comparison


0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

Dispersion (High Tg) Solution/DispersionBlend

Dispersion (Low Tg) Solution

Binder Type

Tens

ile S

treng

th (M

Pa)

MD Tensile Strength (Mpa) CD Tensile Strength (Mpa)

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

Dispersion (High Tg) Solution/DispersionBlend

Dispersion (Low Tg) Solution

Binder Type

Flex

ural

Stre

ngth

(MPa

)

MD Flexural Strength (Mpa) CD Flexural Strength (Mpa)

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0

5

10

15

20

25

Solution Solution/DispersionBlend

Dispersion (high Tg) Dispersion (low Tg)

Binder Type

Impa

ct S

treng

th (k

J/m

^2)

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Processing EffectMechanical Performance Comparison


0

5

10

15

20

25

30

170C/60sec 180C/60sec 190C/60sec 200C/60sec

Tens

ile S

treng

th (M

Pa)

MD Tens Strength (MPa) CD Tens Strength (MPa)

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0

5

10

15

20

25

30

200C/30sec 200C/60sec 200C/90sec

Tens

ile S

tren

gth

(MPa

)

MD Tens Strength (MPa) CD Tens Strength (MPa)

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0

10

20

30

40

50

60

170C/60sec 180C/60sec 190C/60sec 200C/60sec

Flex

ural

Stre

ngth

(MPa

)

MD Flex Strength (MPa) CD Flex Strength (MPa)

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0

10

20

30

40

50

60

200C/30sec 200C/60sec 200C/90sec

Flex

ural

Stre

ngth

(MPa

)

MD Flex Strength (MPa) CD Flex Strength (MPa)

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0

500

1000

1500

2000

2500

180C/60sec 190C/60sec 200C/60sec

Flex

ural

Mod

ulus

(MPa

)

MD Flex Modulus (MPa) CD Flex Modulus (MPa)

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0

500

1000

1500

2000

2500

3000

3500

200C/30sec 200C/60sec 200C/90sec

Flex

ural

Mod

ulus

(MPa

)

MD Flex Modulus (MPa) CD Flex Modulus (MPa)

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90%

95%

100%

105%

110%

115%

120%

180C/60sec 190C/60sec 200C/60sec

Rela

tive

Impa

ct S

treng

th

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80%

85%

90%

95%

100%

105%

200C/30sec 200C/60sec 200C/90sec

Rela

tive

Impa

ct S

treng

th

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Water absorption (24 hr)

0%

10%

20%

30%

40%

50%

60%

70%

170C @ 60sec 180C @ 60sec 190C @ 60sec 200C @ 60sec

Volu

me

Cha

nge

(%)

Soak Vol % of Initial Dry Vol % of Initial

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Water absorption (24 hr)

0%

5%

10%

15%

20%

25%

30%

35%

200C @ 30sec 200C @ 60sec 200C @ 90sec

Volu

me

Cha

nge

(%)

Soak Vol % of Initial Dry Vol % of Initial

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Chemistry Advantage



Summary

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Summary

Composite usage in automotive is growing – addressing need for light weighting

Interest in renewable materials is growing – addressing need for “green”

New materials need to meet or exceed performance requirements

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Summary

New acrylic-based thermosets satisfy all trends

Can meet automotive interior specifications

Enable lighter, thinner parts

Allow high fiber content composites (reduce use of non-renewable materials)

Eliminate VOCs

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Thank You for Your Attention

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Material Characterization of Natural Fiber – Acrylic ... · Material Characterization of Natural Fiber – Acrylic Thermoset Composites ... ASTM D638 -10 Flexural ... Material Characterization