Properties of elastomer composites based on graphene nanoplatelets and carbon nanotubes C. W. Karl1, M. Klüppel2, U. Giese2, A. Lang2 1Institute
of Structural Analysis (ISD), ForWind/Leibniz Universität Hannover, Hannover, Germany 2German Institute of Rubber Technology (DIK) e. V., Hannover, Germany
[email protected]
Motivation & Objective
Experimental: fabrication of elastomer composites
The demand for high-performance elastomers with superior reinforcement and high permeation resistance has driven the research for plate-like nanoscale fillers, in particular Graphene Nanoplatelets. Synergetic effects of graphene in combination with conventional fillers in hybrid systems are investigated.
Elastomer composites Polymer
Plasticiser
SBR
Filler
Absent
Cross-Linking
Carbon Black (CB)
Sulfur
CNT Graphite Graphene
XGnP-M-5
Nanoplatelets
Graphene Banbury mixer
Ingredients without curing system, compounded in internal mixer for 20 minutes Curing system added on mill
Curing, dispersion and mechanical properties The high surface C-type graphene and the CB reinforce in a similar way Slopes for the M-types are higher at small strain 12
Stress [MPa]
The measurement of the vulcanization process (formation of the filler network and chemical cross-linking of polymer chains) has been carried out on the basis of oscillatory rheology using a cure meter
9
6 N121 xg M5 xg M25 xg C750
3
Light microscopy micrograph of a SBR sample (cross-section, DIAS method) containing the graphene type XGnP-M-25
0 0
100
200
300
400
500
Strain [%]
Figure 2: Stress-strain curves of SBR composites with 10 Vol.% of different fillers, as indicated
→ Figure 1: Curing: Graphene nanoplatelets in SBR → Modulus increases and reversion disappears
→
C-type GNPs exhibits a similar reinforcement character as the CB although the specific surface area is about ten times larger. Different behavior of the M-type GNPs: in the first part of the stress-strain curves the stress increases rapidly and then a more moderate increase of the stress is observed.
→
Incubation time is reduced
Publication: M. Klüppel, M. M. Möwes, A. Lang, J. Plagge, M. Wunde, F. Fleck, C. W. Karl, Characterization and Application of Graphene Nano-Platelets in Elastomers, Advances in Polymer Science, 2016
Friction and wear Samples are moved along the substrate with a stationary velocity (5 µms-1 to 15 mms-1; with const FN, p and T); stationary friction, calculation of µ motor
force sensor
Dry friction: significant decrease compared to reference (SBR-CB N121) Best abrasion performance is found for the GNP-type XGnP 750 Friction: SBR on dry glass at 25°C/4kPa
temperature chamber
4
sample substrate
Wear according to DIN 53516 1400
strong stick-slip!
1200
bath
3
dry [-]
move of direction
friction force [N]
3
Wear [mm ]
1000
unfilled N121 UF 198C C750 M25 M5
Range of stationary friction
2
10 10 10 10
1
0 -3 10
Vol.% Vol.% Vol.% Vol.%
N121 UF 198C C750 M25
800 600 400 200
-2
10
-1
10
0
10
v [mm/s]
1
10
2
10
0
Conclusion…so far A plethora of different graphene types were investigated without using expensive monolayer graphene Incubation time is reduced using Graphene Nanoplatelets reducing production time of elastomer composites
Correlation of gas adsorption with mechanical properties: contribution to understanding of interaction Reinforcing mechanisms of graphene in elastomers different from other fillers Graphene type XGnP 750 exhibits lowest friction/abrasion, good dispersion
Financial support of the project “elastomer composites based on graphenes” by the BMBF (grant 03X0110A) is highly appreciated. Special thanks are extended to Prof. Gert Heinrich and Prof. Amit Das from IPF Dresden for the very fruitful cooperation within this project. Prof. G. Lacayo-Pineda from Continental Reifen GmbH is appreciated for performing the gas permeation measurements.
