At the Fakuma-trade show, the additive manufacturer Quarzwerke is presenting fillers for plastics in electromobility, wind power and for films. They are intended to help processors manage the high requirements on the materials in these industries.

The fillers are based on different minerals

Batterien

Energiespeicherung

Elektromobilität

Mobilität

Füllstoffe, mineralisch

Kunststoff Werkstoffe

Füllstoffe für Kunststoffe

Messe Fakuma

kunststoffe-international.com

Füllstoffe, allgemein

Windkraft

Energieerzeugung

Erneuerbare Energie

Kunststoff

Bauwesen

Baustoffe

Folien

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Additive

Fillers Improve Batteries and Wind Power Plants

Transparent polyethylene films can now be produced with antimicrobial and electrically conductive properties as well. This can be achieved by combining several films with the relevant property profiles. The surface conductivity of the films can also be increased by using a suitable new coating technique. The article describes the newly developed special compounds required for this and demonstrates their industrial feasibility. 

Compound

Special Compounds: Transparent, Conductive, and Antimicrobial 

The RadiciGroup High Performance Polymers Business Area is adding significantly to its global production capacity with new construction and installations in North America, Europe and China.

The new plant in Mexico with an area of 20,000 m<sup>2</sup> is part of the investment strategy in North America

16:9

Thermoplaste

Compoundeure

Dienstleistungen

Handel

Radici Increases Production Worldwide

With a newly developed process from Entex it was possible to compound an injection grade compound of PLA with a 50 % wood flour content.

The PLA compound with 50 % wood flour content was successfully produced on Entex’s planetary roller extruder

Compounding PLA Formulations with a 50 % Wood Flour Content, without Premixing

Extrusion

Kunststoffverarbeitung: Verfahren

Extruder

Kunststoffverarbeitung: Maschinen und Komponenten

Extrusionsanlagen

Biokunststoffe

Compoundieren

Kunststoff-Aufbereitung

Direct to Highly Filled Bioplastics

There is still a need to catch up in terms of ion leaching and hydrolysis resistance of the materials used to date for fuel cells. Specially developed PPS represent one possibility for this.

Fuel cells are becoming increasingly important as a drive technology in the vehicle sector

Material Improvements Make Fuel Cells More Reliable

Automotive

Elektronik

Brennstoffzelle

Stromversorgung

Brennstoffzellen

Technische Kunststoffe

Fahrzeugbau

Hochleistungskunststoffe

Getting Fuel Cell Vehicles Fit for Use

Two new inorganic yellow pigments based on iron oxide and zinc oxide respectively are designed for coloration in a temperature range of between 220 and 260 °C.

The yellow pigments are used for all common polymer materials as well as for engineering thermoplastics even at the highest production temperatures

Pigmente, bunt

Farbstoffe und Pigmente

Farbstoffe

Yellow for High Temperatures

Polymaker will offer the Polymaker PC-r 3D printing filament made from recycled polycarbonate (PC). The PC for the filaments comes from materials supplier Covestro and consists of a combination of recycled plastic waste and virgin material.

The combination of recyclates and virgin material reduces the<sub> </sub>carbon footprint of the polycarbonate and still allows it to be extruded into filaments

Filamente für additive Verfahren

Andere Werkstoffe

Werkstoffe für additive Verfahren

Additive Fertigung

Polycarbonat

Kunststoff-Rezyklat

Water Bottles Become Filaments

Atomic force microscopy can be used to determine various properties of polymer surfaces. However, until now it was still necessary to change the hardware on the probe for different measurement methods.

With the Tosca series, all AFM measurements can be carried out with only one actuator body and thus without hardware exchange

Characterize Plastic Surfaces More Easily with Atomic Force Microscopy

Messtechnik

Prüfen von Kunststoffen

Polymethylmethacrylat

Measurements without  Hardware Exchange

The new mobile communications standard 5G is advancing steadily. This development is also increasing the demand for materials that facilitate and ensure the high transmission rates for 5G signals. Plastics manufacturer Covestro has presented a corresponding thermoplastic polyurethane (TPU).

Covers for cell phones must not only protect the devices from shocks, but also allow mobile signals to pass through without interference

Polyurethan

Cell Phone Covers Made from TPU

Continuous fiber-reinforced thermoplastic composites have also become established with thin-walled housings for consumer electronics and information technology. Not only do they offer high stiffness and help to reduce weight, but also enable the integration of classy appearance and functions. What is more, if the housings are produced using the hybrid molding process, costs, processing steps, and cycle times can be reduced.

The Carbon 1 Mark II smartphone from Carbon Mobile was developed in Germany. The matt-black carbon fibers lend the smartphone a classy high-tech look

Composites Reduce Weight and Simplify Production of Electronics Housings

Composite-Halbzeuge

Glasfasern / -matten

Verstärkungsstoffe

Kohlenstofffasern / -matten

Faserverbundwerkstoffe

Kunststofffasern

Organobleche (gewebeverstärkte Thermoplast-Halbzeuge)

Lightweight to Fit in a Pocket

Electrical architecture in an E-car is significantly more challenging than for conventionally powered vehicles. Particularly for insulation of high-voltage (HV) components, the demands on the materials used are increasing. With specially-tailored materials for electric vehicles, challenges in automotive high-voltage technology can be overcome.

Insulation of high-voltage components in electric vehicles makes high demands on the materials used

Polyamide Specialties for Electromobility

Polyamide

High Voltage in Cars

For many components, the use of metal-replacing plastics is an attractive possibility e. g. to save weight and benefit from enhanced design freedom. In various applications, however, the thermal conductivity of the polymers is of equal importance. There are different additives that can be used to enhance this property. In the development of two polyamide families, Domo Engineered Materials investigated which of those additives are especially useful to this end, and applied Light Flash Analysis to examine the materials.

By way of adapting the specimen, the LFA 467 HyperFlash device from Netzsch enables both through-plane and in-plane TC measuring

Which Fillers Are Best Suited for Thermally Conductive Plastics, and How They Can Help Replace Metals

Heat Transfer with Plastics versus Metals

The interfacial tightness of hybrid polymer-metal parts such as injection-molded connectors represents a decisive quality characteristic. Until now, however, there has been a lack of suitable measurement technology with which to quantify the media tightness of such molded parts. A new method delivers significantly more accurate results than previous test methods.

The DDP method enables more accurate determination of the tightness of polymer-metal hybrids

Measurement Method for the Exact Leakage Determination of Polymer-Metal Hybrid Parts

Verbundwerkstoffe / Werkstoffverbunde

Stecker

Elektromechanik

Steckverbinder

How Tightly Sealed are Connectors Really?

CFRP components are often in continuous use under harsh environmental conditions, for example in aircraft and motor vehicles. If any damage occurs, the CFRP structures are simply replaced by new components in most cases. This is mainly due to the high cost of established repair methods. With a newly developed process, defective CFRP structures can now be repaired locally much more easily.

Fig. 1. Overview of the simulation-based repair method for CFRP components: the method enables targeted repair of the damaged area

Process for Repairing CFRP Components without Machining

Repairing instead of Replacing

Colored plastics are not just a marketing gimmick, but fulfill important functions with technical components. In particular, they warn of hazards and permit the fast and direct identification of components. However, when coloring such plastic components, the processors are faced with several difficulties. For example, the colorants used must exhibit long-term resistance to high temperatures and must not impair the polymer’s mechanical properties. Therefore, when selecting the colorant, compounders and processors must observe several important points.

How Plastics Processors Find the Most Suitable Colorants for High-Performance Polymers

Masterbatches

Farbkonzentrate (Batches)

Farben, flüssig

Colors for the High-Performance Sector

Modified Conductive Compounds Make It Possible to Manufacture Bipolar Plates from a Bipolar Film Coil

Bipolar plates are one of the key components of fuel cells and redox flow batteries. They consist of plastics compounds highly filled with electrically conductive materials. To save space, cut costs, and reduce weight, there is increasing demand for the production of thinner plates without compromising robustness and service life. This can be achieved using modified polymers. With a new technology, bipolar plate films based on these modified polymers can be processed as coils.

Sustainable energy sources are of vital importance for society’s future power supply. Since wind and solar power are subject to fluctuation due to changing weather conditions, the generated energy must be held in medium or long-term buffer storage. The ideal solution for this task is provided by so-called redox flow batteries. These generally take the form of 40-ft containers which, as electrochemical converters, can store and deliver large amounts of energy. Another possibility is fuel cells that convert fuels such as hydrogen into electrical energy. This technology is becoming increasingly popular for mobile and portable applications and is already being used for trucks, cars, trains, boats, domestic energy supply (cogeneration), and independent power supply units, e. g. for data centers.

For these technologies to become established in the market, further development of bipolar plates, as the central functional elements of fuel cells and redox flow batteries is necessary. Bipolar plates are a key component of fuel cells and redox flow batteries. Conventional carbon-containing bipolar plates usually consist of thermoplastic or thermoset matrix materials with a high content of conductive fillers such as graphite, carbon black or carbon nanotubes. Although made from plastics, bipolar plates must have very good electrical and thermal conductivity. To achieve suitably high conductivity, the plastic must be filled with up to 80 or 90 wt. % conductive material. Here, the binding polymer plays a crucial role in preventing the compound from becoming brittle and ensuring optimum processability, although it only makes up 10 to 20 wt. % of the compound. For long and economical use of bipolar plates, high electrical conductivity, resistance to degradation, and mechanical stability under load are required.

Polypropylene (PP) and polyolefins in general are frequently used as the polymers for bipolar plates. But for special requirements, other materials such as polyphenylene sulphide (PPS), polyvinylidene fluoride (PVDF), and phenolic resins are also used. Although highly filled graphite bipolar plates based on PP, polyethylene (PE), PVDF, and PPS offer high durability and can be manufactured economically, users are also increasingly demanding thinner, weight-optimized components to save space, reduce weight, and cut material costs. Low thickness and high durability are very conflicting requirements for such high conductive-filler loadings and make the achievement of this goal even more challenging.

By modifying the plastics used in bipolar plates such as PP, PE, PVDF, and PPS, their mechanical properties can, at least within certain limits, be adapted to the required specification and, through impact strength improvement, for example, be made more flexible or ductile. This is essential for the manufacture of thin plates. By using special impact modifiers, Eisenhuth GmbH & Co. KG has been able to produce thin, highly filled, very conductive bipolar plate films as coils in a continuous process (Fig. 1). In this process, polyolefin block copolymers additionally containing ethylene-propylene-diene-monomer rubber (EPDM) were produced with varying graphite content.

The starting point was the production of highly filled compounds. Compounding was carried out on twin screw extruders from Collin, Leistritz, and Battenfeld. On these machines, various modified PP, PE, PVDF, and PPS compounds with a carbon content of about 80 wt. % were produced and pre-conditioned for the shaping process. The next important step comprised processing them into thin films on a suitable continuous production unit.

Modified Films Achieve the  Required Values

The average thickness of the films was well below 1mm and for the most part between 0.5 and 0.8 mm (Fig. 2).

During production, however, the film can be precisely adjusted to the specification so that the required thickness can be ensured to a tenth of a millimeter in serial production. The tensile strength of the plates produced was between 4 and 11 N/mm² (Fig. 3), which is lower than that of the reference material.

It should be remembered, however, that the measurements were not carried out on a standard test bar but on the film itself, which is only about 0.6 mm thick. Further trials to improve tensile strength are currently in progress. The electrical resistivity values of the different material types are higher than those of the reference material (Fig. 4). However, it should be borne in mind that thinner plates compensate for the somewhat poorer electrical conductivity.

The films also open up new processing options. Until now, suitable shaping methods for producing bipolar plates have been hot pressing and injection molding. In these processes, the preconditioned material is generally fed into a heated compression or injection mold. In the case of compounds with a thermoset matrix, a chemical curing reaction under heat must take place before the plate can be removed from the cavity.

With thermoplastic matrices, on the other hand, the compound must first be melted and then brought below the melting or glass transition temperature of the particular plastic before demolding. In hot pressing or injection molding, the technically challenging options consist in directly shaping the required structures or producing unstructured sheet blanks instead.

With the latest technology, graphite compound films can now be processed as coils (Title figure). In a similar way to stamping, the films are drawn down from a coil and processed by stamping/bending to produce the final structured plate (Fig. 5).

The new technology represents a further important step in automated manufacture of conductive compound films to achieve the economy of scale effect.

In this way, the overall costs of fuel cell or battery systems can be significantly reduced. The mechanical properties obtained are comparable with those of graphite-filled, pressed or injection molded bipolar plates. Electrical conductivity, too, lies within a range that is suitable for the application. In view of the current legal framework conditions specified in particular by the EU Commission, there is an ever more pressing need for action to make mobility emission-free. The films described can make an important contribution towards greater acceptance of fuel cell technology.

Eisenhuth GmbH & Co. KG  

https://www.eisenhuth.de

Ausgabenartikel

The modified polymers enable films to be processed  as coils

Fig. 1. By modifying the highly filled plastics, considerably thinner bipolar plate films can be produced than was previously the case 

Fig. 2. Film thickness of the processed compounds and comparison with reference materials (filling degrees in brackets): the thickness of the plates ranges between about 0.5 and 1 mm

Fig. 3. The tensile strength of the different films is lower than that of the reference materials. However, the reference materials are also considerably thicker (3 mm) 

Fig. 4. The electrical resistance of the compounds (filling degrees in brackets) is higher than that of the reference materials. However, this is compensated for by the lower thickness of the films

Fig. 5. Stamped graphite compound film: the bipolar plate is produced by the stamping/ bending process 

KU 6-21_Eisenhuth - Hauptartikel

 Dr. Thorsten Hickmann is CEO of Eisenhuth GmbH & Co. KG, Osterrode, Germany; <a href="mailto:t.hickmann@eisenhuth.de">t.hickmann@eisenhuth.de</a>

Dr. Thorsten Derieth works in marketing and application technology in the Fuel Cells and Batteries Department of Eisenhuth; <a href="mailto:t.derieth@eisenhuth.de">t.derieth@eisenhuth.de</a>

Read the German version of the  article in our magazine Kunststoffe or at  <a href="https://www.kunststoffe.de/a/fachartikel/duennere-bipolarplatten-fuer-brennstoffz-326015" target="_blank">www.kunststoffe.de</a>