ENSACO® Conductive Carbon Black for polymer ... - Timcal Graphite

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ENSACO ® Conductive Carbon Blacks in LDPE
Volume Resistivity (Ohm.cm)
Volume Resistivity (Ohm.cm)
10 8
10 6
10 4
10 2
10 0
10 4
10 3
10 2
10 1
10 0
Various carbon black in LDPE MFI 0.3 and 36 (g/10 min)
E250 G LD 0.3
E250 G LD 36
N472 LD 0.3
N472 LD 36
P-type LD 0.3
P-type LD 36
0 5 10 15 20 25 30 35
Carbon Black Concentration (%)
ENSACO ® Conductive Carbon Blacks in PP
PPH MI54 (230 °C/5 kg) with various conductive carbon blacks
E250 G: high structure - low surface area
N472: high structure - high surface area
1 10
MFI (230 °C/5 kg) (g/10 min)
100
Influence of the carbon black type on the resistivity.
Relation between resistivity and melt flow index:
Compounding and processing: twin screw extruder Haake PTW16 and realization
of tapes.
At same structure level, the carbon black with the lowest surface area has the
smallest impact on fluidity reduction.
Volume Resistivity (Ohm.cm)
10 5
10 4
10 3
10 2
10 1
10 0
Influence of the carbon black type and of the MFI of
the starting polymer on the resistivity:
Compounding: laboratory Brabender internal mixer.
Processing: compression moulding.
The higher the structure of the carbon black, the lower the percolation
threshold.
At equal structure, the carbon black of lower surface area gets an advantage
on resistivity that may be coming from the easier dispersion resulting
in smoother compounding.
The higher the meltflow index of the starting polymer, the lower the
percolation threshold.
171
24
13.50% E250 G
15% E250 G
10
strands pellets + pressed
plaques
6
4.6E+10
54
pellets +
injection moulding
Influence of carbon black loading and processing
on the resistivity:
Compounding: ZSK25 twin screw extruder.
Processing: injection moulding.
Injection moulding generates more shear than compression moulding.
The closest to the percolation, the more visible is that effect. A concentration
safety margin can overcome this phenomenon.