0. Process Characterization of Bio-filler SMC
Casey Blabolil and Paula Watt

1. Green Cost effective Lightweighting
Why Bio-Filler?
Weight reduction
Targeted for volume cost parity to CaCO3
Local renewable feedstock with no food value
Industrial market for farmers’ crop by-product
USDA and State BioPreferred purchasing programs
Green Cost effective Lightweighting

2. Why not Bio-Filler? Overcoming Barriers Water absorption
Reduced with thermal treatment
Rheological differences
Wetout, resin demand, thickening, flow
Thermoset cure effects
Avoided with choice of precursor and treatment controls
Mechanical performance
Overcoming Barriers

3. Understanding differences
SMC Characterization
Compression molding
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4. Understanding differences
SMC Characterization
SMC Formula
Formula
CaCO3
BioFiller
Ingredients
%BOW
UPE Resin solution
10.8
14.7
LPA
Styrene
2.7
3.7
Peroxide
0.3
0.4
Inhibitor
0.2
Pigment
3.0
4.1
Mold release
1.3
1.8
Thixotrope
Filler
43.1
22.6
Thickener
0.5
0.7
Glass Fiber
27.0
36.8
Formula
CaCO3
BioFiller
Ingredients
%BOV
UPE Resin solution
19.3
LPA
Styrene
4.9
Peroxide
0.5
Inhibitor
0.4
Pigment
3.8
Mold release
2.3
Thixotrope
0.2
Filler
29.6
Thickener
0.9
Glass Fiber
19.0
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5. Understanding differences
SMC Characterization
Rheological Behavior
Thickening profiles
Squeeze flow rheometry (PPT)
Cure Characteristics
Dielectric analysis (DEA)
Reaktometer Monitoring
Mechanical Properties
Flexural and tensile strength and modulus
Izod impact, notched
Water absorption
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6. Understanding differences
Brookfield Paste Thickening
Brookfield DV-III Ultra Programmable Rheometer
Calibrated with Bookfield Calibration Fluids 12500, 30000, and
SMC paste samples weighing between g were poured into 500 ml cans after addition of the thickener.
Viscosity index was measured periodically at 5 rpm using spindle TF for 36 s.
A heliopath was used to avoid cavitations during measurement.
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Brookfield Paste Thickening
Thickening profiles
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Squeeze flow rheometry
Premix Processability Tester (PPT)
Test principles developed with Dr. Meinecke –University of Akron
Instrument commissioned by Premix, Built by Interlaken Technology
The instrument is a hydraulic press with 7.62 cm diameter parallel plates equipped with a load cell to measure stress as a function of sample compression.
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9. Understanding differences
Squeeze flow rheometry
Test geometry
3 plies of SMC are stacked and placed between the plates, which are initially separated by a 10 mm gap.
A 10% precompaction to 9 mm is applied prior to start of test data collection.
The platens then close at 2 mm/s to 66% compaction.
The position is held for up to 5 s to monitor stress relaxation.
The platens then open and the sample is removed.
Stress is measured during compression and during the relaxation hold time. r h v F
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Squeeze flow rheometry
Typical raw data
precompaction stress
steady state flow
platen stopped
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11. PPt Squeeze flow Testing
Squeeze flow rheometry r h v F
Viscosity calculations based on the Stefan equation for shear flow. An infinite plate assumption is employed as a modification for plug flow.
apparent stress
apparent viscosity
shear rate
power law model
F = load
r = plate radius
h = plate separation
v= closure rate
n = power law index
PPt Squeeze flow Testing

12. Understanding differences
Squeeze flow rheometry
Results
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Squeeze flow rheometry
Stress strain curves
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Squeeze flow rheometry
Viscosity vs. shear rate (average of 5 curves each)
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Squeeze flow rheometry
Stress Relaxation
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Rheology Data Summary
Data
Filler
Brookfield 2-day paste viscosity
Brookfield 30-day paste viscosity
PPT SMC precompaction stress
PPT SMC compression modulus
PPT SMC yield stress
PPT SMC yield strain
PPT SMC viscosity at 10 sec-1
Power Law Index
Relaxation time
(M cps)
(MPa)
(%)
(s)
Bio-Filler
9.8 15
0.56
0.22
1.04
5.6
1.3
0.18
2.3
CaCO3 11
19.5
0.23
0.98
6.1
1.0
0.28
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17. Understanding differences
Dielectric Cure Analysis
Signature Control System SmartTrac® with a 2.54 cm diameter sensor embedded in a cm x cm mold.
Samples were molded at 150 °C for 2 min at roughly 7 MPa pressure on 0.32 cm stops.
Impedance was measured at 1 kHz.
Gel time was defined at the down turn of the resulting impedance curve, and cure time was the point at which the curve plateaus to a predefined slope limit.
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18. Understanding differences
Dielectric Cure Analysis
Theory
Impedance is defined as the total opposition a device or circuit offers to the flow of an alternating current (AC) at a given frequency.
SMC charge completes the circuit and carries current via dipole flipping which is affected inversely by the viscosity of the material.
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Dielectric Cure Analysis
data
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Reaktometer Monitoring
SMC Technologie (Dr. Derek GmBH)
Test prEN ISO 12114
4.72 in x 9.84 in mold, thickness range 0.03 in to 0.67 in
Equipped with thermocouple, pressure transducer, displacement transducer and a dielectric sensor
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Reaktometer Monitoring
Temperature and pressure –1/8”
Temperature ( °C)
CaCO3
Soy filler
time (s)
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Reaktometer Monitoring
Temperature and pressure – 1/4”
CaCO3
Temperature ( °C)
Soy filler
time (s)
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Reaktometer Monitoring
Impedance and displacement – 1/8”
CaCO3
Displacement (mm)
Soy filler
time (s)
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Reaktometer Monitoring
Impedance and displacement – 1/4”
CaCO3
Displacement (mm)
Soy filler
time (s)
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Cure Data Summary
1/8” data
1/4” data
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Mechanical Performance
Instron 3366
Specimen cut from compression molded 12 in x 12 in X 1/8 in panels
Flexural strength and modulus ASTM D790
Tensile strength and modulus ASTM D638
Izod impact (notched) ASTM D256
Water absorption ISO 62 (1)
Density ISO 1183
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Mechanical Performance
Properties
SMC from Molded specimen
BBC
density
Flexural Strength
Flexural Modulus
Tensile Strength
Tensile Modulus
Notched Izod
H2O Abs
(%)
(g/cc)
(MPa)
(J/m)
Bio-Filler SMC 53
1.4
133
7870 75
6460
1020
0.9
std dev 13
1230
953
220
0.05
Std density CaCO3 SMC 11
1.8
190
10000 70
12000
1000
0.08
Glass bubble low density
1.2
160
7000 65
8000
700
0.2
Low filler low density
1.5
100
8500
1100
0.6
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Conclusions
Rheological test comparisons
Paste thickening response was not affected
In SMC squeeze flow tests the compaction stress was higher for the bio-filler samples, suggesting less loft
The CaCO3 SMC exhibited a stress overshoot at yield, not seen with the bio-filler
Viscosity, at low shear rates, was somewhat higher for the bio-filler material but, with its lower power law index, at high shear rates the curves converge
Relaxation time for the bio-filler SMC is greater than the CaCO3 SMC, which may account for the yield overshoot
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Conclusions
Cure analysis comparisons
The shape of the impedance curves skews the calculated times, inflating the gel time for the CaCO3 SMC and the cure time for the bio- filler SMC
Cure timing based on the impedance curves was very similar
At 1/8” the z-direction shrinkage with the bio-filler was greater but at 1/4” no significant difference was seen, more work is needed to confirm or disprove this
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Conclusions
Mechanical performance
The bio-filler SMC provided 22% weight savings vs. the standard density SMC
The bio-filler has a 53% BBC, much higher than other offerings
Flexural strength was lower for the bio-filler SMC but the tensile strength was at par to the CaCO3 and low density SMCs
Flexural modulus was at the same level as other low density materials, although the tensile modulus was somewhat lower.
Impact was similar to the standard density SMC
Water absorption is higher than for a CaCO3 SMC but at similar levels to the lower filler, low density SMC
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Acknowledgements
Funding
Ohio Soy Council
Dr. Coleen Pugh, University of Akron Polymer Science
Members of the Pugh Research Group
Collaborating business partners
Agri-Tech, Union Process and Bunge
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32. Thank you
Questions?