1. The Influence of Conductive Carbon Blacks on Rubber Properties
Distributor of Ensaco Products
The Influence of Conductive Carbon Blacks
on Rubber Properties
- New Developments & Applications -

2. Conductive Carbon Blacks
Structure
Main carbon black properties
Surface Area
Surface Quality
Rheological
Mechanical
Electrical
properties
Main rubber properties

3. Conductive Carbon Blacks
High Structure
CB aggregate
High ‘void volume’
High ‘DBP absorption’
DBP > 170 ml/100g

4. Conductive Carbon Blacks
High Structure
other parameters being similar
Longer incorporation times
Easier ultimate dispersion
Better surface finish
Higher extrusion speed
Higher Mooney viscosity
Lower cure time
Higher hardness
Higher modulus
Lower tensile and tear strengths
More compounding flexibility
Higher conductivity at lower loading

5. Conductive Carbon Blacks
High Structure Blacks bring
Higher Conductivity at Lower Loading
+CB
Conductive Network
++CB e-
CONDUCTOR
Polymer _ +
! e-
rv ~ Ohm ·cm
? e-
Polymer
INSULATOR + _
rv ~ Ohm ·cm
All CB … but ...

6. Conductive Carbon Blacks
High Structure Blacks bring
Higher Conductivity at Lower Loading
‘Structure-Volume SV ’ equivalency *
SV= j * (CDBP+24)
r [W*cm]
CB %
105
1015 10 20 30
Percolation Curve
SV r jc
* G. Kraus, J. Polymer Sci., 13, 8, 601 (1970)

7. Conductive Carbon Blacks
As high structure blacks take up more space/volume, one can achieve the same filling level and consequently the same conductivity at a lower concentration

8. Conductive Carbon Blacks
Structure
Main carbon black properties
Surface Area
Surface Quality
Rheological
Mechanical
Electrical
properties
Main rubber properties

9. Conductive Carbon Blacks
High Structure & High Surface Area
‘Furnace Process’
porosity
High Structure & Low Surface Area
‘MMM Process’ - ENSACO™
no porosity

10. Conductive Carbon Blacks
High Structure & Low Surface Area
Good dispersibility and excellent ultimate dispersion
better mechanical performance and smoother surface finish
tend to minimize curing time
reduced inhibition of cure agents
temper the viscosity increase imparted by the high structure

11. Conductive Carbon Blacks

12. Conductive Carbon Blacks

13. Conductive Carbon Blacks
Structure
Main carbon black properties
Surface Area
Surface Quality
Rheological
Mechanical
Electrical
properties
Main rubber properties

14. Conductive Carbon Blacks
Surface Quality
A high oxygen content inhibits cure agent and increase cure time
A high graphitization favors
electrical conductivity
thermal conductivity
ENSACO™ - ‘MMM Process’
TOF-SIMS surface analysis: VERY LOW O― CONTENT
RX Crystallographic analysis: HIGH GRAPHITIZATION

15. Conductive Carbon Blacks
Some Rubber Applications
BELTS: conveyor belts, transmission belts...
HOSES: fuel hoses, discharge hoses…
PROTECTIVE COATINGS, LININGS...
FLOORING
POWER CABLES: easy strippable, insulator and conductor shielding...
FOOTWEAR: shoe sole...
AUTOMOTIVE INDUSTRY: fuel injection systems...
HEALTH: surgical tubing...
SAFETY: safety systems for windows & doors
ROLLERS: printing rolls...
SEALS: o-rings, pipe gaskets...
CEMENTS & PUTTY
HEATING ELEMENTS
PTC SWITCHES
ANTICORROSION SYSTEMS
Engine mount ANTI-VIBRATION SYSTEMS
...

16. Conductive Carbon Blacks
Incorporation in an unlimitted number of elastomers and elastomer blends

17. Practical Applications
Conductive NEOPRENE conveyor belt cover compounds
NBR conductive hose compounds
FKM conductive compounds
NR engine mount / anti-vibration system

18. Conductive Carbon Blacks
HS & High SA
HS & Low SA

19. Practical Applications
Conductive CR Conveyor Belt Cover Compound
30 phr

20. Practical Applications
NBR Conductive Hose Compounds
25 phr

21. Practical Applications
FKM (Fluoroelastomer) Conductive Compounds
Experimental data provided by DuPont Dow Elastomers, Japan

22. FKM Conductive Compounds
rejected
Lower Mooney Viscosity

23. FKM Conductive Compounds
Cured properties:
177°C / 10 min
Shorter Vulcanization Time

24. FKM Conductive Compounds
Same
Volume Resistivity

25. FKM Conductive Compounds
Lower Compression Set

26. FKM Conductive Compounds
Higher Moduli

27. FKM Conductive Compounds
Higher Tensile Strength

28. FKM Conductive Compounds
Lower Elongation at Break

29. FKM Conductive Compounds
Same Hardness

30. FKM Conductive Compounds
High Structure & Low Surface Area
Carbon Blacks enable to compound and make Viton® A conductive (20 phr)
Special thanks to DuPont Dow Elastomers, Japan

31. Practical Applications
NR engine mount / anti-vibration system
Ensaco 150 G
Medium-high structure black with a VERY LOW surface area
DBP = 165 ml/100g
BET = 44 m²/g
required hardness and modulus at low loading
higher rebound / lower hysteresis
excellent resistance to fatigue / dynamical properties:
lower storage modulus
much lower tangent delta

32. Carbon Black Conduction Mechanisms
N. Probst, E. Grivei, Third International Conference on Carbon Black, Mulhouse (F), Proceedings (10/2000).
Conductive CB ’s
build a ‘ network ’ at low concentration
the ultimate conductivity depends on
the DBP at a given pressure
the contact resistance
low [O-] content
==> pure CB ’s
==> [CB + polymer]

33. Carbon Black Conduction Mechanisms
N. Probst, E. Grivei, Third International Conference on Carbon Black, Mulhouse (F), Proceedings (10/2000).

34. Carbon Black Conduction Mechanisms
CB as such, in air
0.4
0.35
0.3
0.25
Resistivity (W·cm)
0.2
0.15
0.1
0.05
100
200
300
400
500
Pressure (kg/cm 2 )
No Significant Difference

35. Carbon Black Conduction Mechanisms
CB as such, in air
0.4
0.35
0.3
0.25
Resistivity (W·cm)
0.2
0.15
0.1
0.05
0.2
0.4
0.6
0.8 1
1.2
1.4 3
Density (g/cm )
Clear Differentiation of Conductive Carbon Blacks

36. Carbon Black Conduction Mechanisms
CB in polymer versus CB as such, at the same VOLUME fraction
>> jc
‘ tunneling ’ / polymer film between the CB particles
100
SBR, NR...
crystalline elastomers 10
Resistivity in Polymer (W cm)
polyolefins 1
‘ direct contact ’ between the CB particles
0.1
0.1 1 10
Resistivity in Air (W·cm)

37. Conductive Carbon Blacks
Another vision of conductive CB networking
New generation of compounds
More compounding flexibility
Higher conductivity at lower CB loading
Another combination of properties
Rheological
Cure
Compounding
Mechanical
Dynamical
Electrical