1. Thermoelectric modules based on melt-mixed polypropylene/CNT composites
Petra Pötschke, Jinji Luo, Beate Krause
Abteilung Funktionale Nanokomposite und Blends, Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany

The thermoelectric characterization of polypropylene/CNT composites is presented. It is shown how the addition of various additives can produce p- and n-type materials, which are essential for a thermoelectric module.


2. Polypropylene composites filled with boron- or nitrogen doped CNTs for thermoelectric application
B. Krause¹, V. Bezugly², S. Hampel³, P. Pötschke¹
1 Leibniz-Institut für Polymerforschung Dresden e.V.,  01069 Dresden, Germany;
2 Institute for Materials Science and Max Bergmann Center for Biomaterials, TU Dresden, 01062 Dresden, Germany; Life Science Inkubator Sachsen GmbH & Co. KG, Tatzberg 47, 01307 Dresden, Germany;
3 Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW), Helmholtzstraße 20, 01069 Dresden, Germany

The present study investigated whether the doping of CNTs with nitrogen or boron can significantly influence the TE properties of their PP composites. Doping CNTs with p-type boron led to higher positive Seebeck coefficients, whereas the introduction of n-type nitrogen containing CNTs led to PP composites with negative Seebeck coefficients.


3. Overview of thermoelectric materials based on polymers and CNTs
P. Pötschke, J. Pionteck, B. Krause
Abteilung Funktionale Nanokomposite und Blends, Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany

A systematic overview of thermoelectric properties of polymer/CNT composites is given. The influence of the CNT type, the polymers and other additives on the TE behaviour is shown. Additionally, results of a thermoelectric module in zig-zag-structure are presented.


4. Liquid-chromatographic product purification of highly blue-emitting carbon dots (CDs)

F. Schilfarth 1,2*, V. Michaud 1,2, C. Damm 1,2 and W. Peukert 1,2
1 Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany,
2 Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany

Carbon dots (CDs) are fascinating fluorescent particles < 10 nm, which combine high fluorescence quantum yields (QY) and good biocompatibility and can be synthesized by cheap, green and simple techniques. In literature it was already proposed that CDs consist of a carbon core and highly fluorescent fluorophores which are supposed to be attached to the surface of the CDs.


5. CNT-containing silicones in calendaring applications for highly conductive functional layers
Sergei Wittchen, Minoj Gnanaseelan, Kristin Trommer
Forschungsinstitut für Leder und Kunststoffbahnen gGmbH (FILK)

The processing of low-viscosity silicone masses with the aid of calendering offers low-shear incorporation of CNTs into the polymer mass for the production of electroconductive functional silicone sheets. Due to the lower shear stress and extension flows during calendering, the carbon nanofibers are not mechanically damaged and a peroclation network can be formed. In this project, the formulations and process conditions were developed and foils of approx. 400 ?m thickness were continuously produced. The process can easily be implemented on an industrial scale, without further optimization steps. A continuous process enables the production of defect-free electroconductive foils with good mechanical properties. The mechanical and electrical tests carried out confirm the predicted properties of these functional films.


6. Synergistic behaviour between CNTs and CF in polymer matrices
Kristin Trommer, Maren Lehmann
Forschungsinstitut für Leder und Kunststoffbahnen gGmbH (FILK)

The synergistic effect between carbon nanotubes (CNTs) and carbon fibres (CF) in a polyurethane matrix was investigated. Two variations are possible. On the one hand, the CNTs form the network and carbon fibres act as synergist and vice versa the carbon fibres build up a network and the CNTs play the role of the synergist. An appropriate procedure for the mass preparation is an unidirectional low shearing process, like calendering in a three roll mill. In both cases, the tests regarding electrical conductance (conductivity, percolation) and heating behaviour (heat output, temperature rise) were carried out using thin layers of the polymer matrix. Layers prepared with CNT network and CF synergist can be preferably used at a voltage in the range between 12-24 V. Materials with CF network and CNT synergist are most suitable in low voltage applications between 1-6 V.


7. Advanced fiber characteristics by carbon nanotubes – What we did not expect
 Andres Petr1, Steffen Oswald1, Robert Heider1, Johanne Neuhof2, Silke Hampel1
1
Leibniz Institute for Solid State and Materials Research Dresden;
2 Faserinstitute Bremen e.V.

Carbon fiber (CF) reinforced plastics were widely used as construction elements where weight saving is an important issue. We tried to further increase the stability of such elements by generation of a hierarchical structure of CF and carbon nanotubes (CNT). The direct growth of CNT on CF should increase the mechanical stability of the fiber polymer composite. This will also occur if not all CNT are very strongly bound to the CF due to a CNT dispersion in the matrix without CF will also increase the mechanical stability of the composite but much less effective. More important than the strong bonding of the CNT are the presence of suitable surface groups on the CF and the CNT for a strong interaction with the used polymer. We learned that the concentration of such groups is strongly reduced during the growth of CNT. Therefore an additional oxidation step after the growth of CNT to produce new surface groups is very important.

As a catalyst for the CNT growth we used electrochemically deposited Co-nanoparticles which were oxidized in air to avoid the reaction of metallic cobalt with the CF at the temperature of the CNT growth.

Even with CF grafted with CNTs without the final oxidation step we got an improved pull out value of the fiber. An appropriate surface modification of the CF equipped with CNT will further increase the interaction of the fiber with the polymer matrix and improve the mechanical properties.


8. In-line Monitoring and Optimization Potential of a Three Roll Mill Dispersion Process
Valea Kim Wisniewski1*, Ulf Köpke2, Hauke Voormann, Bodo Fiedler1
1 Institute of Polymers and Composites, Hamburg, Germany
* corresponding author: valea.wisniewski@tuhh.de
2 EXAKT Advanced Technologies GmbH, Hamburg, Germany

Incorporation of carbon nanoparticles is still the bottleneck of every industrial scale masterbatch production. In the current BMBF project “Scale Nano2Industry” the TUHH, BÜFA Composite Systems and EXAKT Advanced Technologies GmbH are working hand in hand on a large-scale production of a masterbatch based on OCSiAl SWCNT Tuball 75.
SWCNT exhibit outstanding electrical and mechanical properties and are thus the first choice for ESD applications, enabling high-performance coating solutions.


9. Measuring Surface Energy Heterogeneity of Nanomaterials by Inverse Gas Chromatography

Sabiyah Ahmed1, Meishan Guo1, Majid Naderi1, and Daniel Burnett2
1Surface Measurement Systems Ltd., Alperton, London, HA04PE
2Surface Measurement Systems Ltd., 2125 28th Street SW, Suite 1, Allentown, PA 18103, USA

The study and applications of nanomaterials such as carbon nanotubes (CNTs) have gained tremendous interest in recent years, due to their exceptional structural, electrical and mechanical properties. These nanomaterials however are often energetically inhomogeneous, exhibiting a wide range of lower and higher energy sites. Therefore, a surface energetic heterogeneity profile can provide more comprehensive information on the nature and population of these surface sites.

Finite concentration Inverse Gas Chromatography (IGC) experiments allow for the determination of the aforementioned surface energy distributions which more accurately describe the anisotropic surface energy for real materials. In this work, the surface energy heterogeneity of commercial multi-walled CNTs was measured, relating to the effects of different modifications (i.e. annealing and oxidation).


10. Industrial Way for production of High Quality Carbon Materials

Federico Micciulla, Claudia Cencetti, Pierpaolo Pustianaz , Mario Cossì, Riccardo Cossi
Qi Technologies, Italy

Demand for carbon-based materials is on the rise given the highly specialized, value-add role they play in diverse applications, including electronic devices, smart clothing, aerospace field, sensor, new high efficiency batteries for green energy storage and in safeguarding the environment, particularly our waters.