This document summarizes the performance of lubricants based on silicone copolymer chemistry. It begins with an introduction to silicones and their molecular structure. It then discusses the properties of lubricants made from phenyl/fluoro silicone copolymers, including their wear resistance, high temperature stability, and low coefficients of friction. Greases made with phenyl/fluoro silicone copolymers are shown to demonstrate better high temperature performance compared to other common lubricant technologies. The document concludes by summarizing the test results, showing the copolymer-based greases offer improved properties such as thermal stability and corrosion resistance.

1. Silicone Copolymer
Based Lubricants
Chad Chichester, Dow Corning
Molykote® Lubricants

2. Introduction
• Brief Siloxane Primer
• Fluoro/Phenyl Siloxane Copolymer
• Neat Fluid & Additized Fluid Performance
• Fluoro/Phenyl Copolymer-based Grease
• Molecular Structure Design Based Development
2

3. What is Silicone?
3
Terminology Definition
Silicon The silicon atom or silicon metal
Siloxane
Typically a polymer with Si-O-Si
repeating backbone (PDMS)
Silicone Generic term for Si-based materials
A Si O Si O Si A
CH3
CH3
CH3
B CH3
CH3
nm
28.0855
14Si
Silicon
A = end block
B = functional branch group
m = Methyl Siloxane repeating unit
n = functional group repeating unit
A
B
A

4. Silicones – Functionalized organo chemistry
with Si-O-Si backbone
• Strong bonds: Si-O (460 kJ/mol) vs. C-C (348 kJ/mol)
• Long bonds: Si-O (0.164 nm) vs. C-C (0.153 nm)
• High bond angle: Si-O-Si (143º) vs. C-C-C (110º) = Flexibility
• Low steric hindrance: Unencumbered Oxygen
• Low glass transition temperature (148 K)
• Low Temperature Flowability
• High oxidative stability PDMS (573 K) to PPMS (649 K)
• Thermal-viscous stability: PDMS (15 kJ/mol) vs. PAO (30 kJ/mol)
• Viscosity indices over 300
• Permanent shear stability: Very low monomeric friction
• Low volatility (even low viscosities)
• Plastic and rubber compatibility
• Chemical resistance
• Water Insolubility
4
= Si = O = C = H

5. Three Primary Types of Silicones
• “Standard” silicones
• Dimethyl fluids are usually silica-thickened
• Poor metal-to-metal lubrication
• Excellent rubber and plastic lubrication
– L: Low loads
– E: Resists moisture, some chemicals
– T: -50 to 200oC temperature range
– S: Low speeds
• Usually Lithium thickened
• Widest temperature range siloxanes
• Improved metal-to-metal vs. PDMS
– L: Low to moderate loads (poor E.P.)
– E: Resists moisture, oxidation and
corrosion
– T: -70 to 250oC temperature range
– S: Moderate speeds
• Usually fluorocarbon-thickened
• Excellent chemical resistance
• Better load capacity & wear resistance
– L: Moderate to high loads
– E: Harsh chemical and solvent
environments
– T: -40 to 230 oC temperature range
– S: Slow to moderate speeds
Dimethyl
Silicone
Phenyl-
Methyl
Silicone
H3C –Si – O – Si – O — Si – O – CH3
CH3 CH3
n
CH3
CH3CH3CH3
H3C –Si – O – Si – O — Si – O – CH3
CH3 CH3
n
CH3
CH3C6H5CH3
Fluoro
Silicone
H3C –Si – O – Si – O — Si – O – CH3
CH3 CH3
n
CH3
CH3
CH2
CH3
CH2
CF3

6. What if…?
6
Lubricity
High
temperature
stability
Output is a Silicone Phenyl/Fluoro Copolymer Base Fluid
• So far, Viscosity ranges from ≈ 400cSt – 5000cSt (@ 50/50 Ratio)
• Additive acceptance near traditional lubricant base fluids
Module “L“ Module “T“
Phenyl
Functionality
Fluoro
Functionality
Variable
Ratio
Variable
Viscosity

7. GREASES | PASTES | OILS | COMPOUNDS | DISPERSIONS | ANTI-FRICTION COATINGS
7
Module “L“ Lubricity of Fluid
Additives now enable respectable
lubrication performance as
compared to other technologies

8. Wear Resistance of Neat Copolymer Fluids
8
DIN 51350
• As Fluoro content wear resistance as expected
• Phenyl/Fluoro synergy against wear at lighter load condition
Fluid Ph:F 400 N load 800 N load
Average Wear Scar Diameter
Phenylmethyl Silicone 100:0 Not measurable Not measurable
Phenyl Fluoro
Copolymer Fluid
75:25 1.53 mm Not measurable
50:50 1.48 mm 2.82 mm
25:75 1.81 mm
Fluorosilicone 0:100 1.18 mm 1.17 mm
0.55 mm

9. Wear Resistance through Additization of 50:50 Si-Copolymer
9
69%
71%
55%
58%
56%
45%
49%
55%
0%
18%
59%
57%
54%
59%
30%
27%
57%
59%
33%
30%
0
0.5
1
1.5
2
2.5
3
Additized (400N) Additized (800N)
Baseline Neat Fluid (400N) Baseline Neat Fluid (800N)

10. SRV Measurement Results
10
0.08
0.09
0.1
0.11
0.12
0.13
0.14
µ (f15) µ (f30) µ (f90) µ (f120)
CoF
75:25
50:50
25:75
0:100 (FS)
DIN 51834-4
T = 50ºC, Freq. = 50 Hz, Load = 300 N, Stroke = 2 mm
In case of 100:0 (Phenylsilicone) not measurable
Ph/F Ratio:

11. 4-Ball Wear Comparison with Existing Technologies
11
Chemistry
Viscosity
-35°C
Viscosity
40°C
Viscosity
100°C
Viscosity
Index
4-ball Wear
Scar
(DIN 51350)
(400 N)
4-ball Wear
Scar
(DIN 51350)
(800 N)
75/25 Phenyl/Fluoro 304 k 408 63 229 1.53 Too high
50/50 Phenyl/Fluoro Solid 328 56 239 1.62 3.05
25/75 Phenyl/Fluoro Solid 314 55 242 0.55 1.81
Poly-α-olefine Solid 345 37 155 0.77 Too high
Polyol-ester Solid 171 21 145 1.03 2.30
Poly-glycol Solid 471 86 268 0.53 0.65
Phenyl-methyl-
polysiloxane
17,400 100 29 322 Too high Too high
Solid 244 40 220 Too high Too high
Fluoro-silicone 44,410 188 36 241 1.18 1.71
PFPE (branched) ? 80 10 108 1.01 1.58
PFPE (linear) ? 159 45 338 1.57 2.07

12. • Higher Fluoro content => higher wear resistance
– One interesting anomaly with 25% phenyl
• Higher Fluoro content => lower CoF
• Additives soluble in copolymer improve wear scar
an average ~50%
• Comparable wear resistance to other synthetic
formulations
Summary of Copolymer Lubricity
12

13. High Temperature Stability of Fluid
13
Module “T“

14. Thermal & Oxidative Comparison with Existing Technologies
14
Viscosity
Viscosity
Index
TGA DSC
Evaporation
200°C, no cover
%
Chemistry
-35°C 40°C 100°C VI 150°C 200°C 250°C
Ox.
Onset
Temp
6 h 24 h 7 d
75/25
Phenyl/Fluoro
304 k 408 63 229 99.1 98.8 98.6 282°C 0.02 0.04 0.13
50/50
Phenyl/Fluoro
Solid 328 56 239 99.4 99.2 99.0 283°C 0.04 0.13 0.47
25/75
Phenyl/Fluoro
Solid 314 55 242 99.6 99.4 99.0 277°C 0.13 0.27 0.65
Poly-α-olefine Solid 345 37 155 99.3 99.0 97.4 205°C 0.54 1.94 7.85
Polyol-ester Solid 171 21 145 99.6 99.5 96.5 203°C 0.62 3.77 13.38
Poly-glycol Solid 471 86 268 98.1 88.1 - 154°C 26.69 66.41 87.18
Phenyl-methyl-
polysiloxane
17.4 k 100 29 322 99.7 99.5 99.1 307°C 0.08 0.19 0.48
Solid 244 40 220 99.7 99.4 99.1 366°C 0.11 0.28 1.46
Fluoro-silicone 44.4 k 188 36 241 99.7 99.3 97.2 246°C 1.74 4.99 18.50
PFPE (branched) ? 80 10 108 99.5 98.9 93.4 348°C ? 5.0 ?
PFPE (linear) ? 159 45 338 99.7 99.6 99.3 330°C ? 8.0 ?

15. 15
8000
7000
6000
5000
4000
3000
2000
1000
0
0 10 20 30 40 50 60
Thermal Stability Open Cup (250ºC)
Viscosityat40ºC(mPas)
450
400
350
300
250
200
150
100
50
0
0 20 40 60 80 100 120
Days
Thermal Stability Closed Cup (250ºC)
Viscosityat40ºC(mPas)
75:25 50:50 25:75Ph/F Ratio:

16. Summary of Copolymer High Temperature
Properties
16
• Higher Phenyl Content => Higher Thermal Stability
– Higher Viscosity Index
– Less Weight Loss
– Higher Onset Oxidation Temperature
• Very good thermal performance among other
synthetics

17. Grease Made with Phenyl/Fluoro Copolymer
• PTFE thickened, no additives
• Two viscosities: 460 mPa-s (390 cSt) and 750 mPa-s (640 cSt)
• FAG FE9 high speed, high temperature testing
• SKF EMCOR corrosion testing
• Other typical grease properties testing
– Penetration
– Dropping Point
– Bleed & Evaporation
– etc…
• Lithium Complex Thickened Copolymer
17

18. 18
Test Method
Norm,
Specification
Silicone
grease
PFPE
grease
1
PFPE
grease
2
PFPE
grease
3
Ester
grease 4
50/50
Copolymer
(460 mPas)
50/50
Copolymer
(750 mPas)
Base Oil Technology Ph-Si PFPE PFPE PFPE
Polyol-
ester
Si-
Copolymer
Si-
Copolymer
High temperature
performance: FAG
FE9, (6000 rpm &
1.5kN); F50
DIN 51821 @
220°C
not
tested
max
service
temp is
200°C
15 h 44 h 42 h 87 h
(@ 180°C)
62 h 66 h
High Temperature (220ºC) FAG FE9 Test
DIN 51821(mod)

19. 19
Test Method
Silicone
grease
PFPE
grease 1
PFPE
grease 2
PFPE
grease 3
Ester
grease 4
50:50
Copolymer
(460 mPas)
50:50
Copolymer
(750 mPas)
Base Oil Technology Ph-Si PFPE PFPE PFPE
Polyol-
ester
Si-Copolymer Si-Copolymer
Corrosion
resistance: SKF
EMCOR 1 week, dest.
water
1 0-1 0 1-2 0 0 0
SKF EMCOR Testing (DIN 51802)

20. 20
Si-Co
polymer
1.4g/cc
PFPE
2g/cc
Test Method
Norm,
Specification
Silicone
grease
PFPE
grease
1
PFPE
grease
2
PFPE
grease
3
Ester
grease 4
50:50
Copolymer
(460 mPas)
50:50
copolymer
(750 mPas)
Base Oil Technology Ph-Si PFPE PFPE PFPE
Polyol-
ester
Si-
Copolymer
Si-
Copolymer
Density @ at 20°C ISO 2811
1,05
g/cm³
1,95
g/cm3
1,95
g/cm3
1,95
g/cm3
1,01
g/cm3 1,42 g/cm3
1,42 g/cm3
Density comparison to other High Temperature
Lubricants

21. 50:50 Copolymer Grease Performance Summary
21
Test Method
Norm,
Specification
Silicone
grease
PFPE
grease 1
PFPE
grease 2
PFPE
grease 3
Ester
grease 4
50:50
Copolymer
(460 mPas)
50:50
copolymer
(750 mPas)
Base Oil Technology Ph-Si PFPE PFPE PFPE Polyol-ester
Si-
Copolymer
Si-
Copolymer
Density @ at 20°C ISO 2811
1.05
g/cm³
1,95
g/cm3
1,95
g/cm3
1,95
g/cm3 1,01 g/cm3
1,42 g/cm3
1,42 g/cm3
Consistency DIN 5118 NLGI # NLGI 2-3 NLGI 2 NLGI 2 NLGI 2 NLGI 2-3 NLGI 2 NLGI 2
Dropping Point DIN 220°C 198°C 169°C 161°C > 295°C 285°C 302°C
Flow Pressure at -40°C Kesternich test
1150
mbar
1175
mbar
700 mbar 575 mbar 775 mbar 950 mbar
1525 mbar
(800 mbar
@ -35°C)
Bleed after 24H 200°C
Fed Stan 791-
321.2
9.59% 8.74% 12.28% 10.00% 4,50% 3,67% 3,19%
Evaporation after 24H
200°C
Fed Stan 791-
321.2
1.75% 0.08% 0.08% 0.14% 2,44% 0,33% 0,36%
High temperature
performance: FAG FE9,
(6000 rpm & 1.5kN); F50
DIN 51821 @
220°C
max temp
is 200°C
15 h 43 h 42 h
87 h @
180°C
62 h 66 h
Four Ball Wear Scar DIN 51350 2,61 mm 1,45 mm 1,18 mm 0,72 mm 1,03 mm 1,18 mm 1,18 mm
Four Ball Weld Load DIN 51350 1400 N 7500 N > 8500 N > 7500 N 2600 N 2300 N 2300 N
Corrosion resistance:
SKF EMCOR 1week, =<1
DIN 51802 1 0-1 0 1-2 0 0 0
Copper Corrosion ASTM, DC 1b 1a-1b 2b 1b 2c 2b 2b

22. Characteristic Test method Li-complex grease PTFE grease
Ph/F ratio 50/50 50/50
Base oil viscosity (40°C) 246 mPa*s 790 mPa*s
Additives No additives No additives
Penetration (unworked/60/
10 k/100 k strokes)
DIN ISO 2137 258 / 261 / 282 / 303 324 / not tested
Bleed/Evaporation (24 h/200°C) 0.46%/1.17% 4.58%/0.44%
Dropping point DIN ISO 2176 340°C 332°C
Flow pressure DIN 51805 925 mbar (-35°C) 1125 mbar (-40°C)
Emcor corrosion (7 d) DIN 51802 0 4
Water resistance (3 h, 90°C) DIN 51807 1 0
DIN 4 ball test (ok load) DIN 51350 1700 N 1900 N
DIN 4 ball test
(wear scar 400 N, 1 h)
DIN 51350 1.05 mm 1.02 mm
FE 9 (B10/B50)
(6000 rpm, 1.5 kN, 220°C)
DIN 51821 Not tested 52 h/69 h
Lithium Complex-Thickened Copolymer Grease Properties
22

23. 23
NLGI PAPER # 1505 - ”High Temperature Grease Utilizing New Silicone
Based Fluids” by Dr. Manfred Jungk, Dow Corning, Wiesbaden, Germany
Feedback to Molecular Structure Design
Molecular Structure to Rheology
Q: Percent functional branch content (m/DP)
L: Length of alkyl branch (Carbon atoms)
J: Type of branch (A, P, C, F)
Z: Atomic length (Silicon and Oxygen atoms)
Rheology to Tribology

24. Add Copolymer to Modeled Structures
• Generalized Polysiloxane Design Model
– Q: Percent functional branch content (m/DP)
– L: Length of alkyl branch (Carbon atoms)
– J: Type of branch (A, P, C, F)
– Z: Atomic length (Silicon and Oxygen atoms)
• Branch Types
– PDMS – D: Dimethyl branch
– PFMS and PDPS
• F: Fluorine branch
• DP: Diphenyl branch
– PPMS and PCMS
• P: Phenyl branch
• C: Cyclohexyl branch
– PAMS and PPAMS
• A: Alkyl branch
• PA: Phenylalkyl branch
• Phenyl : Fluoro Copolymer
24

25. • Silicones have exceptional oxidative & thermal stability, and
high viscosity indices.
• Flexible structure of new Ph/F copolymers allows design of
fluids with high thermal stability and improved wear resistance.
– Phenyl fucntional groups for good thermal properties
– Fluoro functional groups for wear and friction properties
– Variable Phenyl:Fluoro ratios
– Improved additive acceptance
• Greases formulated with Copolymer show promise
• Molecular Structure Modeling system to aid in product
developement.
– Variable viscosities
Summary
25

26. 26
Thank you!
Special Thanks to:
Dr. Manfred Jungk and Dr. Christian Kranenberg, Dow
Corning, Wiesbaden, GmbH