Nanomaterials and nanoproducts are widely used in automotive transportation.
First of all, for the manufacture of tyres (carbon black, silica, materials, etc.). nanostructured), for the reinforcement of mechanical parts and joints through the use of nanocomposites, but also to lighten chassis and interiors, or to reduce the weight of the increase battery life, in particular. Another potential benefit of nanos is to reduce the quantities of raw materials used and thus reduce production costs. and recycling. The forum on 30 May 2016 took stock of the applications and potential of nanoproducts in the automotive sector. It also addressed the risks associated with their use in the automotive industry. production, their use and their end of life.
Emeric FréjafonInstitut national de l'environnement industriel et des risques, Institut national de l'environnement industriel et des risques (National Institute for Industrial Environment and Risks) (INERIS)
What are the applications of nanomaterials in the automotive industry?
Batteries, aluminium structures, joints: new applications for nanopowders of silicon
Laurent KOSBACH, CEO, Nanocyl S.A.
Commercial and future applications of carbon nanotubes in the automotive industry
Francis PETERSconsultant, former World Head of Materials Projects, and Raw Materials, Michelin
Pneumatics and nanomaterials
Christophe BRESSOT, INERIS
Road pavements (nano) in the automobile: what advantages, what promises, what uncertainties?
Jean-Jacques Perrier introduced the session and introduced the speakers. He discussed the following topics that were discussed: release of nanomaterials during their use or by release (abrasion, wear), the tensions between lower consumption and lightness versus resistance and emissions (through tyre friction or wear of photocatalytic coatings).
He pointed out that the participants included representatives of Renault (Ms. Meyer, member of the NanoRESP Alliance), PSA, Total... and encourages them to take part in the discussions.
1 - Overview of nanomaterials applications in the automotive industry
Emeric FRÉJAFON, National Institute for Industrial Environment and Risks (INERIS)
The use of nanotechnology is increasing, with a turnover of world sector in net growth: $1,000 billion in 2013 compared to $300 billion in 2008. billion in 2010. In 2013, 400,000 tons of nanomaterials were declared in France.
But the data are approximate and lack consistency.
Current and potential applications of nanomaterials in vehicles.
Source: Hessian Ministry of Economy, Transport, Urban and Regional Development
Nanomaterials in transport
They intervene in the motorization elements (motor, energy storage, circuit, etc.). fluidic), in structures (chassis, body, trim, interior, security, lighting, (e.g. windows, bumpers, appearance), surface coatings) or consumables (fuels, oils, filters, catalysts, tyres...). They provide mechanical properties, thermal, electrical, chemical, optical allowing weight savings and durability, recyclability, safety, performance, aesthetics or compatibility.
For example, carbon nanotubes are used to strengthen and impart very special properties (electrical and thermal conductors), which are sources in particular of economic gains. Other nanomaterials allow weight gains and therefore reduce the vehicle's fuel consumption. A challenge raised in 2006 was also that of the
Replacement of non-recyclable materials with nanocomposites to achieve high rates of recyclability close to 100%.
Fibre materials can be used to reinforce inner panels with the following properties self-supporting. Surface treatments are a source of added value (anti-fouling and self-cleaning, scratch resistance, even energy capture).
INERIS is working to assess situations that may present risks and to determine the appropriate criteria and tools for hazard characterization and exposure assessment. Concerning uses for cars, this includes examining whether the materials used bring new or increased risks due to new dangerousness, new dangers, new behaviours never seen before in the field. This monitoring concerns industrial sites as well, storage places, user exhibitions or vehicle recycling. At of the integration of nanomaterials, there have been risk control issues since the
R&D stages before products, up to waste management stages after use.
At the end of life, we are thus confronted with complex questions. If we take the example of glass surfaces with a nanostructured surface treatment, it will be determined whether these surface nanostructured flat glasses can be considered in the same way as the same untreated flat glasses, and therefore to assess whether the classification of the products changes. when adding surface nanostructuring. Another example could be assessment of the suitability of current energy recovery methods for materials of tomorrow, therefore, to know whether a product that is nanostructured on the surface or in the mass has an identical behaviour of the same non-nanostructured product, when incorporated into an incineration process.
INERIS has developed three specific platforms to characterize hazards and assess the risks:
- the Secure Nano-Platform (S-Nano) aims to assess the physical hazards of products such as explosion, flammability or powders nanostructured. It also makes it possible to study the release of nanomaterials in use, during their ageing or during their incineration.
- The life science platform has testing facilities dedicated to the study of pulmonary toxicity, both in in vivo and in vitro approaches. Under GLP (Good Laboratory Practice), it allows the production of reference data.
- The waste study platform (ARDEVIE) is a joint INERISCNRS-CEREGE centre. it carries out waste ageing tests to evaluate possible transfers to soil and groundwater.
The objectives of these approaches are to identify the phases at risk and to propose mitigation actions.
At workstations, it is essential to check the containment capabilities and the performance of the barriers used. Voluntary normative standards and/or regulations such as NanoCERT are being put in place.
Work is also being done to estimate the environmental impregnation of a unit of production or integration of nano-objects. In particular, a methodology has been developed for the point for monitoring nanomaterials in the industrial environment (flux estimation, deposition prediction, assessment of concentrations in
With regard to the life cycle of products, efforts are made to estimate the emissive potential of nanostructured products under mechanical, chemical and environmental constraints, taking into account the aging process.
At the end of the day, studies on a pilot incineration plant make it possible to test the efficiency of the best available techniques in the incineration process, therefore including the kiln torque incineration and effluent abatement techniques.
In conclusion, nanomaterials are sources of high added value in the sector of automotive (e.g. for coatings, batteries, chassis, etc.). All the The difficulty is to be able to provide elements for decisions on cost evaluation and benefits of innovation in a context of uncertain risk data
or even missing. INERIS works both on the production of data and their use ofn the decision-making process prior to bringing an innovation to market.
Questions and exchanges
Caroline Petigny (BASF) :
In the panorama presented, can you tell us if these are nanostructured materials or nano-objects?
In the case of coatings, these are mostly nano-objects (spray and aerosol). There are nanostructured nanomaterials, including polymers with added fillers, or supports on which silica is added (tires). In summary, the materials products are generally nano-structured products in the mass, while lighter products are generally
anti-water repellent and self-cleaning are nano objects in solution.
Philippe Girard (Total, Scientific Directorate) :
The notion of "nano-object linked to something" appears in European legislation. How do you deal with this notion? What releases are possible? Functionality can she be affected?
At Ineris, we treat this subject empirically. We carry out abrasion tests on anostructured surfaces to assess whether the bond is strong and whether it is evolving with the time. We observe that the emissivity sometimes increases with time, so that this link is weakening. Tests on paints and stains, for example, make it possible to
to show that aged surfaces (in a climate chamber) emit nano-objects because the cohesion of nano-objects in the matrix evolves over time. The challenge is to achieve Standardize the way these tests are done (how we do artificial aging, how long the materials are placed in the climatic chamber) to be able to compare the
Louis Sangouard (Collectif Nano de Saclay):
What do you mean by the "compatibility" property provided by nanomaterials?
If you want to give a plastic an electrical property, it is so that you can paint it. And so to make the paint compatible with the material.
What is the proportion of nanomaterials in tyres versus other applications?
Carbon black and silica are the most widely used today, in particular because of their mass use in tyres.
Vincent Rouinvy (Centre for Environmental Information and Action for Health): I'd like to come back to the dangerousness. There are composite plastic materials that carry harmful compounds. How do we address the actual effects?
The challenge is to assess not the danger of nano-objects but the matrix in which they find each other. It is the risk that is in focus, depending on the uses and the exposure they are exposed to. ...are causing. In short, we look for danger with a material. If there is, we is interested in salting-out to estimate emissivity. Life cycle assessment (LCA) is being promoted, which includes aging. It is crucial to achieve standardization of measurements (metrics, sizes, loads) and to frame protocols to evaluate emissivity.
Are suppliers in control of their products in the supply chain?
It is not easy to gather information along this chain. These are the limits BtoB relationships. Requests can be made to suppliers on their specifications, but sometimes the information has difficulty in passing through. According to the Group National Working Group on Labelling of Consumer Products Containing
nanomaterials, once the definition of "nano" has been agreed upon, a prerequisite to be resolved is traceability along the industrial chain itself, so that the downstream sector has full knowledge of the products it uses.
2 - Batteries, aluminium structures, joints: the new applications for silicon nanopowders
Nanomakers is a spin-off from CEA in 2009, with an exclusive right of use. on laser pyrolysis. This technology makes it possible to produce in particular carbide of silicon. Two innovations and processes have been developed in-house and patented:
- carbon-coated silicon for battery applications;
- aluminium-coated silicon carbide (SiCALU).
Other patents relate to the reinforcement of elastomers to make seals and the containment of nanomaterials to avoid contact (either at Nanomakers or at clients).
The company, based in Rambouillet, has a production capacity of 10 to 20 tons. of nanopowders per year. It has a subsidiary in Japan and many first-class partners. plan in the world.
Due to the bottom-up nature of the process (starting with carbon and silicon atoms), we obtain a very pure product with a homogeneous distribution. The processes are reproducible. The flagship product is high-purity silicon carbide (from the licence CEA). A "mass market" derivative product is due to be released at the end of 2016: it uses a precursor liquid to get a lower cost. Its applications are elastomer seals and metals (including additive manufacture/3D printing).
Precautions concern the packaging: the nature of the product is a loose powder. (40 g/litre) very powdery - it can be compacted by increasing the density by a factor of 10. This results in lower volumes to be transported and lower exposures. We can also put it on hold.
Nanomakers has its own control laboratory (which performs 80 % of tests) at Rambouillet, as well as a reactor with a storage and distribution bank, designed and maintained by Air Liquide. This storage equipment will make it possible to produce 250 tons/year. On each batch, there is a quality control (material certificate).
From the outset, the company adopted a "zero contact" strategy. It carries out the production automatically (with shutters on the reactor) and packaging in watertight containers. Shipments are made in sealed aluminium packaging. The premises are monitored and controls show levels of cleanliness above good number of private or industrial sites.
Nanomakers will invest to automate transfers and packaging and remove any manual intervention, to further limit the risks.
Applications of nanopowders in aeronautics, space, automotive and defence (fuselage, chassis, additive manufacturing) are numerous.
Five major uses in the automotive industry
For vehicles, Nanomaker powders are used mainly for five objectives.
1/ Mechanical or chemical reinforcement
Silicon carbide powders are used as additives for curing elastomers. perfluorinated compounds which serve as seals for semiconductor production machines. They are appreciated for their high purity (Carbon, Silicon), the stoichiometric equilibrium almost perfect, and the absence of metallic traces. Silicon carbide also has a good chemical resistance, which is essential because inside the machines, the oxygenated plasma is very aggressive.
2/ As joints for hot rooms and corrosive atmospheres (engines and exhaust)
3 / Lightening by aluminium. The proof of concept obtained in the foundry shows a Doubled elasticity.
4/ Additive manufacturing by the use of aluminium powders
5/ Batteries (Li-Ion battery upgrade)
There is a great need for innovation to double the specific energy density of batteries, in order to increase the autonomy of the vehicles. The effort is focused on the anode, to replace graphite with a graphite-silicon composite. With silicon the capacity is ten times more important than graphite.
Silicon has to be nanometric, otherwise we are faced with a phenomenon of cracking: during charging, the silicon swells, then deflates during discharge, which causes cracks in the anode. A second problem is the oxidation of the silicon by the other agents.
Today, we know how to produce nanoscale silicon and coat it with carbon (which the protects). The tests are carried out by battery manufacturers (Panasonic, LG Chem, GS Yuasa, Samsung).
Questions and exchanges
What is the extra cost for the final material, with the addition of the nanopowders?
We always look at the added value of our products and the additional price that the customer can pay. If we are talking about lightening, we have to comply with the added value of the materials, variable according to the sector. For cars, the price is 5 to 6 € /kg of weight reduction. In aeronautics, 2 to 3,000 €/kg; for a launcher, 10 to 20,000 €/kg. Aerospace application therefore provides the best return on investment.
How do you test the dosage and proportions?
On metals the 1 % is the reference (less than 2 % by mass). Optimization tests are made by an aluminum metallurgist in conjunction with the University of Wisconsin. We have comparable values for sintered steel (less than 1 %)
How do we explain the efficiency?
By the nano effect, i.e. the very large specific surface area of the product. For example, the "35 nano SiC (silicon carbide)" has a specific surface area of 50 m2./g which allows interaction throughout the network (reinforcement of the material). This reinforcement is obtained with very little material but it should be homogeneously dispersed to benefit from
improvement of the mechanical (or electrochemical for silicon in the batteries).
For traceability, how do you do it?
Each subject certificate has a reference. This gives us the recipe used. All over the phe delivery process, the path of the product is known. On the other hand, for the end of life, we We are starting because we started production for elastomer seals in January. 2015. We are working on these topics within the framework of the European NanoREG project. Isolated nanoparticles are unlikely to be found since, by its nature, the nanomaterial is trapped in the matrix. Its added value is due precisely to its bonds. On the recycling side, we know how to recycle composite powder as well as metallic powder.
3 - Commercial and future applications of carbon nanotubes in the automotive industry
Laurent KOSBACH, CEO, Nanocyl S.A.
It's been years since we became aware of the concerns that may exist around nanoproducts and in particular carbon nanotubes (CNTs). We are are positioned both as a leader in a particular type of product but also as a leader in a particular type of on health, environment and safety issues.
To this end, we participate in European studies (NanoRelease, Deroca, Marina, Sun, NanoSolutions...) that allow us to develop and publish data and to implement before we knew each other. This work allows us to say that our nanotubes are under control.
We focus on four types of industry: transport, energy storage Batteries, fuel cells, electronics (initial market - electrostatic dissipation) and industry (rubber).
The company NanoCyl
Born in 2002, NanoCyl has gone through the scale-up stages from prototypes to the large-scale production. Another challenge is dispersion.
The greatest innovation is in thermoplastics.
(Source: Nanocyl SA)
Applications of carbon nanotubes, multiwall version
Nanocyl's products are intended for a wide range of applications: supply in car energy, hoses, etc. There are also paint solutions for boats (to avoid biocides) and to reduce energy consumption.
Our flagship material is a multi-wall nanotube (MWCNT) which gives a high electrical conductivity to the matrices it occupies
. Named NC7000™, it is industrially produced and covers many applications. Nanocyl holds authorizations in Europe (Reach registration), the United States (PMN) and Canada (NSNSchedule 5).
Multiwall CNT is part of the conductive additive market, as are conductive black carbon (from petroleum products). For the same performance, 2 % of our MWCNT against 20 % of furnace carbon black. This is a major advantage.
Our product is a black powder made of nanotubes with a diameter of 10 nanometers and with a length of 1.5 microns. The black is very deep, and there would be an interest in talking to the future with paint manufacturers.
For tires, the consumption of carbon black in the world amounts to several million tons. In our driver market, the demand for CNT only exceeds not 40 to 50 000 tonnes at present, all types (SW, DW, MWCNT).
The main performances of the multiwall NTC are the electrical conductivity (in the polymers or other matrices), easy incorporation (dispersion by processes that we have mastered), superior retention of mechanical properties (even at very low temperatures), and superior load), recyclability, fire resistance (European results), heat dissipation.
The range of derivative products is extensive: Plasticyl TM for thermoplastics, ElastocylTM for elastomers, epoxy resin (EpoCylTM), organic solvents (OrganCylTM), and especially nanotubes which can be dispersed in water. (AquaCylTM).
Nanotubes for the automotive industry
In the automotive industry, CNTs have three main applications:
- Fuel supply systems (pump, tubing), which require material antistatic (polyamides) for car safety (instead of metal).
- Bumpers and fenders that are painted: the incorporation of CNTs is done in the mass to facilitate colour applications (cost reduction) via a plastic conductivity
Projects are long and require a minimum of 5 years.
For lithium batteries, cathode CNTs are increasingly being used in combination with carbon black: this increases the power and life span.
At the level of structural materials (composites), to lighten the structure by means of composite materials, Nanocyl is not yet well positioned in transport, but the flagship products are in sports products.
For tires, the incorporation of very low doses of multiwall carbon nanotubes allows to establish a balance between silica and carbon black, with an optimum of the resistance to abrasion, consumption and adhesion.
Safety, uses and end of life
In real-world situations, aggregates that behave like industrial inert powders. Two studies by BASF SE (Germany) on animals, carried out for 90 days by inhalation at very high doses, show lung inflammation. transient and localized at the CNT2 deposition site. At the same time, there is a recovery after stopping the exposure.
Nanocyl recommends protective equipment to its customers, including butterfly valves. and a vacuum system with HEPA H14 filters and to follow up on employees from year to year.
The question of the future of these products remains to be addressed in relation to use and ageing.
In thermoplastics and rubbers, CNTs are encapsulated. Not being never isolated, they are not released as such.
At the end of life, products can be recycled for less demanding uses. Incineration is recommended because nanotubes are good fuels that leave only soot.
Questions and exchanges
Patrice-Henry Duchene (PSA's Sustainable Development Delegate):
For the end of life of thermoplastics or carbon materials, you recommend incineration. Can you tell us whether the presence of CNT can be an obstacle to recyclability, as is the case with bromine?
It's less of an obstacle than bromides. We're going in the right direction for recycling. We haven't done any tests for recyclability (and why not do some with PSA by the way?). The presence of CNTs on the market is quite minimal for the moment and the issue has not yet been raised.
Philippe Girard (Scientific Directorate, Total) :
One comment first regarding conductive polymers: you indicated that the recyclability is good but it must be made clear that this concerns plastics for which color doesn't matter.
Returning to the issues of toxicology and exposure in the event of accidental release of NTC, Inserm has published animal studies showing that they do not pass into the blood system. They stay in the lungs where they're either rejected or encysted.
Indeed the products are black! Our toxicologist is following these studies. The studies inhalation studies in animals confirm that lung inflammation is transient. I Stresses that what I am saying here concerns our multi-wall CNTs with the specifications of our product (format, length, tube tangle).
Did the choice you made for multi-walls stem from these established risks?
Our choices can be explained by the stakes of industrialization and toxicity. We withdrew from the single-wall" projects because their prices are very high. It takes several thousand dollars per kg for single-wall CNTs while multi-wall CNTs cost less than one dollar per kg. a hundred euros. However, the single walls have a conductivity far higher than that of multi-walls, which allows them to be mixed at very low rates, of the order of 0.01 %. This raises the question of whether these very low doses are actually dispersed throughout the material.
Vincent Vouinvy (Environment and Health Action Information Centre) :
Could the number of CNTs in the preparations be increased?
It is certain that with rates from 0.5 to 3% it is easier to disperse and guarantee efficiency. However, I am not advocating increasing this proportion, for reasons of unnecessary extra costs if you already have low load performance.
I'm surprised when they say that agglomerates are not dangerous or that the risks are diminishing. I don't quite understand how the properties that give toxicity can disappear with aggregation?
Having larger objects makes the barriers (filters) more effective.
Toxicity should not be disconnected from the biological environment, which varies the state of of nanoparticle agglomeration. We favour a major approach by not Whereas the most toxic form of the free form (nano-object), in order to take into account the difficulty in predicting the form - agglomerated or not - in which the nano-objects. Agglomeration is a means of reducing exposure, not a means of reducing the toxicity of nano-objects.
On the toxicity of the various forms of CNT (single-wall, multi-wall...), it is difficult to determine the toxicity of the various forms of CNT (single-wall, multi-wall...). pronounced generically because CNTs are more a family than a substance.
However, the United States Institute for Occupational Safety and Health (NIOSH) and the Center The WHO's International Agency for Research on Cancer (IARC) has recently formulated a number of recommendations that need to be considered. For example, when NIOSH proposes an occupational exposure limit of 1 µg.m3 for multi-wall CNTs, it emphasizes the
the toxic nature of these objects.
The greatest danger will be in the recovery of the finished product before packaging. We we plan to automate this step.
Philippe Girard (Scientific Directorate, Total) :
Carbon nanotubes are produced naturally by any combustion (in the incineration as soon as there is a catalytic effect). In comparison, industrial combustions and natural (fires) emit hundreds of millions of tonnes of CNT. Production industrial NTC remains limited to a few tens of tonnes per year. It is impossible in
this context to be able to make statistical studies.
Christine Mosset (economist):
Are the nanotubes found in the subway system the result of combustion, train braking, or of manufactured materials? A recent article reported the presence of CNTs in the lungs of Parisian children.
The work of the scientists involved does not correlate between nanotubes and the condition of the lungs examined in these asthmatic children. The article clearly mentioning that the carbon structures found in Paris cannot be correlated with the asthma of the children studied (see penultimate paragraph in Part 4). It is which I expressed in my reply.
Carbon nanotubes like these are found in ice caps! Combustion well regulated naturally produce fullerenes.
Caroline Pétigny (BASF):
The question of origin is not essential, what matters is the health of people. If it there's an exposure you have to treat it from wherever it comes from!
You're right, but there is a question of responsibility. If we incriminate a product that was produced of industrial manufacturing, it is important to intervene to stop these fumes.
The problem is that anthropogenic CNTs cannot be distinguished from those that are produced by the industry. I don't think you can, for example, mark with isotopes. Such a signature to differentiate us is not accessible.
Jean-Marie Pillet (retired):
My question concerns the choice of uses for these materials. I understand the uses apart from the wear parts. On the other hand, it is problematic to use these materials in wearing parts. Shouldn't the precautionary principle be applied here?
Rebounds by Dorothée Browaeys:
In order to put the issue together, I will ask the question of the traceability of your products and the means to ensure it. On the side of the car manufacturers, we hear the leitmotiv: "we don't know if we have nano's or not." This is problematic for the consumer confidence.
Are there solutions for marking the products you manufacture? Can you imagine a logical approach that would start from the fact that you want your product to be recognized for its value, and therefore you want to be able to follow its uses? With this logic, do you think you have solutions so that at the end of a nanomaterial's life, we'll be able to trace its origin. Would there be any proposals in terms of voluntary marking, as in counterfeiting? Would that be relevant? Could this highlight the responsibility of industrialists?
If I get a bumper I won't be able to trace the origin of the NTC. Our responsibility is to follow the products. But, technically, you can't recognize a material only through a chain of custody.
Laurent Sarabando (PSA):
The definitions are not very precise. This is what makes the traceability of nanomaterials difficult. We have reporting systems that support tracking. But, at the of the French mandatory reporting, we have many problems.
4 - Tyres and nanomaterials
Francis PETERS, consultant, former Michelin World Manager for materials and raw materials projects
Carbon black has been used in tires since 1910. It was used to replaces zinc oxide (the grey colour of old tyres) and increase the durability of an factor 40.
In the 1990s, Michelin introduced amorphous precipitated silicas to reduce fuel consumption (about a quarter of the fuel consumed by vehicles is lost in the heating of the tires).
Carbon black and amorphous silica are nanostructured materials. They come in the form of as aggregates, not nanoparticles (aggregate sizes exceed the 100 nanometers). They are introduced into mixers that incorporate them into the rubber. under very high energy. The reinforcement of the tyre requires the formation of high energy between nanostructured additives and rubber. In the tyre, the particles of carbon black or silica do not exist in isolation: they are linked to the rubber macromolecules. It takes a considerable amount of energy to dissociate the
It is necessary to reduce the fuel consumption of vehicles in order to decrease their emissions and reduce the quantities of raw materials used. The pneu is seeking to use new nanomaterials for sustainable solutions.
Transport is responsible for 18 % of CO2 emissions. The rolling resistance of tyres contributes to 20 % of a car's fuel consumption and 30% of a car's fuel consumption. for a heavyweight. The search for new nanomaterials should make it possible to reduce rolling resistance and thus reduce vehicle fuel consumption.
In 2030, the forecasts give 1.6 billion vehicles on the planet! Consumption is worryingly increasing: in 2008, tyre production was already at its highest level in the world. 1.11 billion. To double this production would require twice as many raw materials unless we come up with some new solutions. Efforts are focused on finding ways
to reduce the consumption of raw materials. To protect operators by production we refer to the ISO Standard of "control banding" (developed by the industry). pharmaceutical in 2005); it is a classification by "danger bands" to which are associated with technical levels corresponding to exposure maxima.
The TIP project
In 2005, the world's 11 largest tire companies began work on the sustainable development issues. It is the Tire industry project (TIP) that is being carried by the World Business Council for Sustainable Development (WBCSD), which focuses between other to nanomaterials.
In July 2014, the OECD produced a report entitled "Nanotechnology and tires Greening". Industry and Transport". Experts consider that "nanomaterials promise a sustainable future for the tire industry".
Within the OECD, the Business and Industry Review Committee (BIAC) cooperates with the TIP, which decided in October 2015 at its colloquium in Chantilly, France, to adopt the following recommendations OECD on good practices and to define risk management methods on the entire life cycle of tires.
Emissions of wear particles on roads
In 2006, a tire and road study was launched with funding of approximately one million euros. of dollars a year. The first step taken was the collection of particulate matter on a precise course (a circuit near Clermont-Ferrand). A second system used a machine in Germany at BASt. The wear particles collected are a mixture of bitumen and tyre sizes between 10 and 100 microns.
Another facility (CardnoChemrisk) located in Sweden did not detect any generation of nanoparticles. On the other hand, with studded winter tyres nanoparticles are found.
A study conducted by Ford and published by Marcel Mathissen and his colleagues at the University of Toronto. of Wuppertal concludes that "under normal driving conditions, there is no significant increase in particulate matter". Very fine particles from 30 to 80 nanometres are detected when tires are subjected to sudden braking, skidding, or acceleration.
According to environmental studies carried out in the Paris basin, in Japan in the the Kyoto region, in the Washington DC area, around Los Angeles, Tokyo and in In London, tyre emissions contribute little to fine particle pollution: for PM10, the share related to tyres is approximately 1 % overall. For PM2.5, the
contribution is less than 0.3 %.
Air sampling results for PM10 and PM2.5
5 - Road pavements (nano) in the automobile: what advantages, what advantages, what advantages? promises, what uncertainties?
Christophe BRESSSOT, INERIS
Road wear by the tyre causes emissions of inhalable particles (PM10).
The concentration of PM10 is regulated according to a European Union directive. These emissions have been identified as a major contributor to urban emissions.
In 2012, road transport in metropolitan France will be responsible for 14 to 17 % particulate emissions. The phenomena of mechanical friction, linked to wear and tear of the of roads, tires, clutches and brakes, are responsible for emissions of greenhouse gases. large and diffuse non-exhaust particulate emissions.
Depollution by TiO2 coatings
Self-cleaning and depolluting coatings are available on the market, incorporating titanium nanodioxide (TiO2) particles, which have photocatalytic properties.
The effectiveness of these nanomaterials has been tested in a canyon: the reduction of oxides of nitrogen is 36 to 82 %.
Emissions from road surfaces
The Nano-data Project (APR ANSES 2012) aims to study the emission of nanoparticles from commercial products, according to the uses, and to study their emissivity. A series of tests (polishing) on 30 specimens of asphalt mixes with and without TiO2 did not detect a significant release of titanium.
A machine called FOBAC was implemented in a confined situation. Microscopic observations do not detect titanium on the samples, but the presence of small spherical particles (Ø: 70 nm).
In conclusion, the benefits of this technology can be rationalized but are functions of local climatic conditions (humidity, temperature). The durability of the performance has been little or no study. The risks identified to date are the releases. However, there has been no free particle release observed. As a matrix composite
cement and TiO2, rare cases of releases have been observed. On the other hand, the aerosols shows some nanometric or submicronic emissions (sub-micron) probably of pneumatic origin.
Questions and exchanges
Did you test used tires?
There are no significant differences with new tires.
Can we explain the particularity of studded tires to emit nanoparticles?
This can be explained by the effect of the wood rasp on a material: soft, it will emit large particles; if it is hard, it will emit fine particles.
Is there any point in having TiO2 in pavements? What is the efficiency the destruction of nitrogen oxides in real life cases?
There are also questions about the accumulation of minute doses. When you have thousands of ...tires, we're multiplying by the infinitesimal and we're all liable to get sick...
Under normal traffic conditions, no emission of nanoparticles was found. It it should be remembered that in our air we find on average 5 to 10,000 nanoparticles per cm3.
Most airborne nanoparticles are not manufactured but are linked to natural processes. Smokers, for example, emit 300,000 nanoparticles per year. millilitre of air. Wood heating is also highly emissive. Toxicologist Francelyne Marano discovered CNTs on the device in 2000 when there was no manufacture of nanomaterials at that time. So we have to consider this context as well.
The final discussion focused on the traceability of nanomaterials.