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EFFECT OF AROMATIC OIL ON PHASE DYNAMICS OF S-SBR/BR BLENDS
February 17, 2016 Presented at the Tire Technology Expo & ConferenceHannover, Germany
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A. Rathi1, M. Hernández2, C. Bergmann3, J. Trimbach3, W. Dierkes1, A. Blume1
1University of Twente, Enschede (NL)2Technische Universiteit Delft, Delft (NL)3H&R Ölwerke Schindler GmbH, Hamburg (D)
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PASSENGER CAR TIRE TREAD
Main performance indicators:
Rolling Resistance (RR)
Abrasion Resistance (AR)
Wet Skid Resistance (WSR)
INTRODUCTION
[www.rma.org]
[http://cdn.dlron.us] [http://dothanhyundai.mitchellhyundai.com]
ROAD SAFETY![http://i.ytimg.com]
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MOTIVATION:
EC No 552/2009 - Shift to ‘safe’ process oils with lower PAHs content
Effects on compound properties:
• Improvement in the RR.
• Negative effect on the WSR and AR .
INTRODUCTION
RR
AR WSR
MAGIC TRIANGLE*
*Roughly drawn for UHP tread compound; Source: ETRMA
Black- DAEPurple- TDAEGreen- MES
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SBR/BR blends in different ratios (commonly, 50:50 and 70:30)
Mol.wt.Styrene/
Vinyl
AR
Tg
High-cis BR
S-SBR/BR(50:50/70:30) WSR
Tg
Styrene/ Vinyl
PROCESS OILS:
Improve processability: increase the scope of using high mol.wt. polymers
Improve physical properties: elasticity, flex life, aids filler dispersion.
Extend the rubber compound: increases the free volume of the compound, thereby increasing filler loading capacity
Reduce the cost of final compound
INTRODUCTION
[www.rma.org]
RR
5*Supplied by Trinseo GmbH **Supplied by Lanxess GmbH ***Supplied by H&R Ölwerke Schindler GmbH
POLYMERS:
Functionalized solution styrene-butadiene copolymer (FsS-SBR)*
[Figure provided by supplier]
High-cis polybutadiene (BR)**
[Figure taken from patent: EP1169364 A1]
PROCESS OIL:
TDAE***, a low PAH content aromatic oil
MATERIALS
Tg = -25 °C
Tg = -109 °C
Tg = -49 °C
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TDAE (Treated Distillate Aromatic Extract)
MOLECULAR STRUCTURE(Polarity or aromaticity)
MOLECULAR WEIGHT
Two main properties of a
process oil
Determines the degree of compatibility with the rubber
Mol.wt. = Viscosity = Shear in banbury mixer and improved mixing/dispersion
MATERIALS
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MIXING & VULCANIZATION
1st Stage: Internal Mixer50 rpm, 50 °C; Oil addition stage
2nd Stage: Two roll millR.T.; Curative addition stage
T90 measurement (RPA) & vulcanization at 160 °C
Steps in preparation of S-SBR/BR (50/50) blends with 0/10/20 phr TDAE:
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Inoue et al., Rubber Chemistry and Technology, 1985.Scale bar: 10 μ
STRUCTURE OF S-SBR/BR (50/50) BLENDS
Callan et al., Rubber Chemistry and Technology, 1969.Scale bar: 2 μ
MECHANICAL BLENDING SOLUTION CASTING
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COMPARISON OF Tgeff FROM DSC, DMA, BDS & theoretical
model
Broadband Dielectric Spectroscopy (BDS)PhD Thesis, Kumar Kunal, University of Akron 2009
Dynamic Mechanical Analysis (DMA)www.paralab.ptDifferential Scanning Calorimetry (DSC)
www.netzsch-thermal-analysis.com
CHARACTERIZATION
Lodge and McLeish model
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DSC0 TDAE10 TDAE20 TDAE
CHARACTERIZATION
-100 -80 -60 -40 -20 0 20 40 60 80 100
0,0
0,2
0,4
0,6
0,8
1,0
0 TDAE 10 TDAE 20 TDAE
Tan δ
Temperature (°C)
S-SBR/BR (50/50)DMA
BDS
Single, broad peak associated with the Tg
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SEGMENTAL DYNAMICS OF OIL-EXTENDED FsS-SBR* AND BR
Local motions
<< 1 nm
Segmental mobility
1-2 nm
Chain dynamics
10 nm
Detectable only at very low frequencies
SECONDARY RELAXATIONS(For e.g. β)
GLASS TRANSITION (Tg)
BDS
[PhD Thesis, Marianella Hernández Santana Universidad Complutense de Madrid, 2012]
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Net dipole moment = 0[PhD Thesis, Kumar Kunal, University of Akron 2009]
Net dipole moment ≠ 𝟎𝟎
Reorientation of dipoles on
application of an electric field
Gold electrodes
Polymer film
0)(*1´´´)(*
CZii
ωωεεωε =−= Capacity of the
empty sample holder
MEASURED QUANTITY
Current
)(*)(*)(*
ωωω
IVZ =
ImpedanceVoltage
BDS
[PhD Thesis, Marianella Hernández Santana Universidad Complutense de Madrid, 2012]
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Measured quantity: Complex dielectric permittivity (𝛆𝛆 ∗ = 𝛆𝛆𝛆 − 𝐢𝐢𝛆𝛆𝐢)Real part (Dielectric storage modulus)
Imaginary part(Dielectric loss modulus)
Dielectric dispersion curves corresponding to a Havriliak-Negami Process[PhD Thesis, Kumar Kunal, University of Akron 2009]
𝝉𝝉 = 𝟏𝟏/𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝝉𝝉 is the relaxation time at frequency of maximum loss
BDS
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10-1 100 101 102 103 104 105 106
0,000
0,005
0,010
0,015
0,020
0,025
0,030
ε″
f [Hz]
A) S-SBR/BR (50/50)_0 phr N2X at T = −30 °C
α′
α
Compound Δεα 𝜏𝜏HN (α)(s)
b c Δεα′ 𝜏𝜏HN (α′)(s)
b′ c′
No oil 0.226 1.384 × 10-4 0.609 0.131 0.089 5.317 × 10-4 0.429 1
HAVRILIAK-NEGAMI EQUATION(S) BASED FITTING
153,6 3,8 4,0 4,2 4,4 4,6 4,8 5,0
-2
-1
0
1
2
3
4
5
6
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-log(τ ma
x)
S-SBR/BLEND BR/BLEND VFT Fitting line
1000/T, K-1
S-SBR/BR (50/50) Blend
MOBILITY (segmental motion)
RESTRICTION (segmental motion)
ACTIVATION PLOT: VOGEL-FÜLCHER-TAMMAN (VFT) EQUATION
Tg: Temperature at which 𝜏𝜏max = 100 s
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VOGEL-FÜLCHER-TAMMAN (VFT) EQUATION BASED FITTING
3,0 3,5 4,0 4,5 5,0 5,5 6,0-2
-1
0
1
2
3
4
5
6
7
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- log (
τ max)
1000/T, K-1
BR_0 BR_10 BR_20 TDAE S-SBR_20 S-SBR_10 S-SBR_0
A) Pure polymers (S-SBR & BR)_0/10/20 phr TDAE
-28 °C
-50 °C
-76 °C
-30 °C-31 °C
-90 °C
-99 °C
-50 °C
-43 °C-38 °C-36 °C
-69 °C-58 °C
-54 °C
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Calculate the relevant ‘self-concentration’, ɸs factor.
Calculate the effective local composition, ɸeff.
Calculate the Tgeff for each
phase using a modified Fox equation.
3,6 3,8 4,0 4,2 4,4 4,6 4,8 5,0-2
-1
0
1
2
3
4
5
6
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-log(τ
max)
S-SBR/BLEND BR/BLEND VFT Fitting line
1000/T, K-1
S-SBR/BR (50/50) Blend
Tgeff BDS Model
based
Tgeff(S-SBR) -43 °C -42 °C
Tgeff(BR) -69 °C -60 °C
LODGE & McLEISH MODELT.P. Lodge, T.C.B. McLeish, Macromolecules, 33, 5278 (2000).
CONCLUSIONS
Decoupling of individual S-SBR and BR phases via BDS.
Effect of TDAE on the individual phases by observing the change inTg
eff.
Greater effect of the TDAE is observable on the BR phase.
Tgeff values corroborated with the Lodge and McLeish model for
dynamics of miscible blends*.
*applicable only to the non-oil-extended blends.
1st step towards the final goal i.e., quantification of the partitioning of TDAE.
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FUTURE OUTLOOK
2nd step: To achieve a quantification of the partitioning of TDAE oil ineach phase of the S-SBR/BR (50/50) blend.
To extend the protocol devised for the 50/50 blend to other blend ratios,such as 70/30 and 30/70.
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ACKNOWLEDGEMENT
The authors are thankful to H&R Ölwerke Schindler GmbH (Hamburg,Germany) for the scientific, financial and materials support as well as thepermission to present this work.
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THANK YOU FOR YOUR KIND ATTENTION!