Development of Biopolymers from Soybean

OilAndrew Cascione & Nacú Hernández

Dr. Christopher Williams and Dr. Eric Cochran

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October 10, 2012

Introduction• Asphalt cement commonly modified with

an SBS tri-block copolymer • Kraton’s® formula for asphalt modifiers

20.2 m

Butadiene

• Byproduct of steam cracking process (ethylene production from crude)– (ethylene is also produced from natural

gas which yields no butadiene)

• Gas Phase (explosion hazard)• Polymerization of SBS– Anionic Polymerization• Costly/Oxygen sensitive• Organo metalic initiators

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Butadiene Commodity Trends

$/ m

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ton

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http://www.icis.com

Soybean Oil• Substitute of the rubbery block

• Triglycerides

• 4.6 double bonds

• Chemical modification

– Different polymerization techniques

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$/ m

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Butadiene and Soybean Oil Commodity Trends

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http://www.indexmundi.com

Radical Polymerization-Mechanism• RP consists of 4 main events:

1. Decomposition • This step requires an Initiator capable of forming free radicals.

2. Initiation • The decomposed free radical fragment of the initiator attacks a

monomer, yielding a monomer-free radical.

3. Propagation • Monomer-free radical or polymer-free radicals can attack other

monomers to increase the chain length by 1.

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Radical Polymerization-Mechanism4. Termination

(a) Combination – Two polymer free radicals of different lengths combine to form a

single dormant polymer.

(a)Disproportionation – Two polymer free radicals of different lengths combine to form

two distinct dormant polymers.

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Polymers via Free Radical Polymerization

• Multifunctional nature – Potential to crosslink with at least

one other polytriglyceride– When a fraction of 1/N have

crosslinked (N=# of repeat units)

• Polymers reach their “gel point”• Thermosets

(Courtesy of Richard LaRock)

Linear polymer chains

Ability to flow Will not flowSoybean Oil

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Atom Transfer Radical Polymerization (ATRP)

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Atom Transfer Radical Polymerization (ATRP)

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Atom Transfer Radical Polymerization (ATRP)

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SB Biopolymer

SBS Biopolymer

Soybean Oil

Results

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Rheological Measurements

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SBO- Homopolymer SBS Triblock copolymer

log 10 aTlog 10 aT

T

G’

200

120

160

Asphalt Polymer Blends

• Virgin PG XX-34 blended with…

• 3% Kraton SBS D1101 • 3% Kraton SBS D1118• 3% SB Diblock Biopolymer• 3% SBS Triblock Biopolymer

• Blended polymer and asphalt in shear mixer at 180°C for 2 hours

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Unaged Binder G* (KPa)

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Unaged Binder Phase Angle

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High Temperature Performance Grade

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Asphalt-PolymerBlend

Mass Loss

XX-34 0.43 %

Kraton D1101 0.77 %

Kraton D1118 0.89 %

SB Biopolymer 2.79 %

SBS Biopolymer 2.48 %

SBS* Biopolymer 0.93 %

Not So Good

Big Improvement!19

Low Critical Temperatures

XX-34 Kraton D1101

Kraton D1118

SB Biopolymer

-35.3 -34.7 -34.7 -34.5

PG -34 PG -28

SBS Biopolymer

SBS* Biopolymer

-33.8 -33.1

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Continuous Grade Range

86.7

94.2

89.589.2

95.2

93.4

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Multiple Stress Creep and Recovery(MSCR) Test – Simulated Data

γp = peak strain

γr = recovered strain

γp = unrecovered Strain

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Asphalt-PolymerBlend Temp °C

Jnr

3.2kPa-1Traffic Level Traffic Level

Criteria

XX-34 46 1.55 HHeavy (1.01 – 2.00)

SBS Biopolymer 46 0.90 VVery Heavy (0.51 – 1.00)

Asphalt-PolymerBlend Temp °C

Jnr

3.2kPa-1Traffic Level Traffic Level

Criteria

XX-34 46 1.55 HHeavy (1.01 – 2.00)

Asphalt-PolymerBlend Temp °C

Jnr

3.2kPa-1Traffic Level Traffic Level

Criteria

Multiple Stress Creep and Recovery(MSCR) Test

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Asphalt-PolymerBlend Temp °C

Jnr

3.2kPa-1Traffic Level Traffic Level

Criteria

XX-34 46 1.55 HHeavy (1.01 – 2.00)

SBS Biopolymer 46 0.90 VVery Heavy (0.51 – 1.00)

Kraton D1101 46 0.50 EExtremely Heavy (0.00 – 0.50)

SBS* Biopolymer 46 0.33 EExtremely Heavy (0.00 – 0.50)

SBS* Biopolymer20.2%

Kraton 1101 25.0%

XX-34 4.1%

SBS Biopolymer 6.6%

Passing % Recovery

Failing % Recovery

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Master Curves• Frequency Sweep in DSR from 16 °C - 70 °C• Fit G* data to CAM Model

• Estimated Shift Factors using WLF

• Used Shift Factors to shift δ data

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Next Steps

• Optimization of block copolymer• Comprehensive experimental plan on the

blending method• Micrographs with supporting FTIR Analysis• HMA performance testing• Build Pilot Plant

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Thank You! Any Comments or Questions?

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