Digital Commons, Nicolas Jullien

Digital commons: individual interests to serve a community

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In a world where the economy is increasingly service-based, digital commons is key to developing the collaborative economy. At Télécom Bretagne, Nicolas Jullien, an economics researcher, is studying online epistemic communities, creation communities which provide platforms for storing knowledge. He has demonstrated that selfish behaviors may explain the success of collective projects such as Wikipedia.

From material commons to digital commons

Cities of commons, common areas, commons assemblies: commons are shifting from theory to practice, countering the overexploitation of a common resource for the benefit of only a few, and offering optimistic solutions across a wide range of sociological, economic, and ecological fields.

“Work carried out since the 1960s by Elinor Ostrom, winner of the 2009 Bank of Sweden’s “Nobel” prize for Economics, has led us to abandon the idea of a single choice between privatization of common goods and management by a public power,” says Nicolas Jullien. “She studied a third institutional alternative where communities collectively manage their commons.” This work first focused on natural or material commons, such as collective management of fisheries, then, with the advent of the Internet, on knowledge commons. The threat of enclosures (expropriating commons participants from their user rights) emerged once again, around the subject of handling copyrights and new digital rights.

Nicolas studies online collective groups whose goal is to produce formalized knowledge, not to be confused with forums, which are communities of practices. “A digital commons is a set of knowledge managed or co-produced by individuals,” explains the researcher, citing Wikipedia, Free, Open Source Software (FLOSS), open hardware, etc. In order for a material commons to function, the number of individuals involved must be limited so that members may organize the commons and choose their rules: entry barriers are thus required. “It’s different with digital commons since apparently there aren’t any entry barriers and everyone can contribute freely,” remarks the researcher, who raises the following questions: Why do individuals agree to take collective action for a digital commons when they are not obliged to do so? How can this collective action be organized?

The digital world does not fundamentally change how people function, nor does it change voluntary commitment, but it does produce a mass effect and a ripple effect, which act as facilitators. It allows more specialized people to meet each other using coordinated information systems managed through Internet bots and artificial intelligence… Finally, because it is not very expensive to produce and make available, the fact that people take advantage of commons without paying is of less importance.

 

Selfishness as a driving force for collective action

Are new theories required to understand digital commons? Not according to the researcher, who states, “Technology is certainly evolving, but human beings still work the same way. Existing theories explain people’s involvement in digital commons rather well, along with the way participants are structured around these commons.”

Among these is Marvell & Olliver’s 1993 theory, which established that people weigh cost and opportunity when making a commitment. Collective action is then a gathering of rather selfish individual interests, with varying levels of involvement. And a common denominator is required to remind people about the rules on a higher level. These comprise entrance filters, coordination systems, people who devote themselves to enforcing these rules, and robots who patrol. “If only selfish people were involved, it wouldn’t work,” says Nicolas. Even though interest is purely selfish at the outset, “I’m doing this because I like it, I need to do this, it’s an intellectual challenge, it’s for the good of the world,” individuals soon become interested in adding content to the platforms and following their rules, “and this is the key to how this system works, since the goal is indeed the production of knowledge.”

How selfish are participants in these communities? The researcher and his team, in collaboration with the Université de la Rochelle and the Wikimédia France foundation, studied the social attitudes of Wikipedians, including non-contributing users whose role is often under-estimated. 13,000 Wikipedians were subjected to the “dictator game where you receive a sum of €10 and have to share it with another person. How much of it do you keep?” Following a precise protocol, the game was used to find out if the community produced prosocial behavior, or if individuals already exhibited pro-social preferences that explained their behavior. Two thirds of the participants replied 50/50, well above the usual 40% of people who reply this way when participating in the game. Wikipedians thus have this social sharing norm in common. Better still, whereas earlier studies indicated that Wikipedia contributors had higher-than-average prosocial attitudes for their age, the study did not reveal differences between contributors and non-contributors. “We observed that visiting Wikipedia makes people more likely to demonstrate prosocial (not necessarily altruistic) behaviors.” In other words, compliance with a social norm increases as the sense of a collective develops

 

Economy and digital commons

These studies, at the crossroads between the disciplines of industrial economics and organizational management, will provide engineering programs with food for thought about how organizations manage digital change. The researcher asks a third question: how do digital commons projects impact the economy? First of all, there is an emergence of what, in 1993, the economist Paul Romer referred to “industrial public goods” around which participants seek to position themselves. “I would ideally like to create something like ‘open street map’ without a competitor doing the same thing before I do. So that’s what leads me to work in an open standard,” explains Nicolas. And since there cannot be a multitude of platforms fulfilling the same need, there are increasing yields with adoption: the more time goes by, the more people want to contribute to a certain platform rather than another, and accept its rules even if they do not exactly correspond to what contributors would like.

“What we noticed with FLOSS, we’re noticing with Wikipedia too,” remarks the researcher. Individuals are paid to make sure the references are up-to-date. A whole project involving editing, quantification of information, observation, integration of content produced in the ‘above services’ is developed. This verification momentum provided by the community creates the business. Without that, “if the commons stops evolving,” there is no longer any reason to participate.

“Many other questions still remain,” continues the researcher, “within national and European research on innovative societies and industrial renewal.” These questions have been explored in the past by the ANR CCCP-Prosodie project and are currently being studied by the ANR common project with the Fing, CAPACITY. How are professions (librarians, for example) changing in response to daily contact with the digital commons? What is learned in these commons, “which are like game guilds“? How are the practical skills developed there related to academic skills? How valuable is this on a résumé? Do companies that hire commons developers buy access to the community? For Nicolas Jullien, all these open-ended questions would deserve to be studied by a digital commons Chair.

Read the blog post The sharing economy: simplifying exchanges? Not necessarily…

 

Nicolas Jullien, Communs numériques, Digital commonsAn associate research professor in economics at Télécom Bretagne, Nicolas Jullien has been working on digital commons since his thesis on free software in 2001. He was coordinator of the Breton M@rsouin cluster for measuring and studying digital uses until 2008, and is head of the Étic (evaluation of ICT measures) research group and of the Master’s in ICT Economics co-accredited by the Université Rennes 1. He was a visiting professor at the Syracuse iSchool (in New York State) in 2011, where he led research on communities of online production and has held an Accreditation to Lead Research since 2013. Guided by a curious mind more than any particular taste for developing theories, this engineer, who is a fan of multiview approaches to understanding complex phenomena, will become a member of the Board of Directors of LEGO, a research laboratory for management economics for western France (UBO/UBS/Télécom Bretagne), in January 2017.

Formula 1, composite material

What is a composite material?

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Composite materials continue to entice researchers and are increasingly being used in transport structures and buildings. Their qualities are stunning, and they are considered to be indispensable in addressing the environmental challenges at hand: reducing greenhouse gas emissions, creating stronger and more durable building structures, etc. How are these materials designed? What makes them so promising? Sylvain Drapier, a researcher in this field at Mines Saint-Étienne, answers our questions in this new addition to the “What is…?” series, dedicated to composite materials.

 

Does the principle behind a composite mean that it consists of two different materials?

Sylvain Drapier: Let’s say at least two materials. For a better understanding, it’s easier to think in terms of volume fractions, in other words, the proportion of volume that each component takes up in the composite. In general, a composite contains between 40 to 60% of reinforcements, often in the form of fibers. The rest is made up of a binder, called the matrix, which allows for the incorporation of these fibers. Increasingly, the binder percentage is being reduced by a few percentage points in order to add what we call fillers, such as minerals, which will optimize the composite material’s final properties.

 

composite material, Sylvain Drapier, Mines Saint-Étienne

50 % of the structure of the Airbus A350 is made of composite materials. The transportation industry is particularly interested in these materials.

Are these fibers exactly like those in our clothing?

SD: Agro-sourced composites, using natural fibers like flax and hemp, are starting to be developed. In this regard, it’s a little like the fibers in our clothing. But these materials are still rare. For composites that are produced for widespread distribution, the fibers are short — at times extremely short — glass fibers. To give an idea of their size, they have a diameter of 10 micrometers and are 1 to 2 millimeters long. They can be larger in products that must absorb limited strain, such as sailboards and electrical boxes, in which they are a few centimeters long. However, high-performance materials require continuous fibers that measure up to several hundred meters, which are wound on reels. This is the case for aramid fibers, with the best known being Kevlar, and is the case for glass fibers used to make wind turbine blades, as well as for carbon fibers used in structures that must withstand heavy use, such as bicycles, high-end cars and airplanes …

 

Can these fibers be bound together by soaking them in glue to form a composite?

SD: It all starts with fiber networks, in 2D or 3D, produced by specialized companies. This involves textiles that are actually woven, or knitted, in the case of revolving parts. After this, there are several production methods. Some processes involve having the plastic resin, in liquid form, soak into this network as a binder. When heated, the resin hardens: we refer to this as a thermosetting polymer. Other polymer resins are used in a solid state, and melt when heated. They fill the spaces between the fibers, and become solid when they return to room temperature. These matrices are called thermoplastic, made from the same polymer family as the plastic recyclable products we use every day. Metal and ceramic matrices exist too, but they are rarer.

 

How is the choice of fiber determined?

SD: It all depends on its use. Ceramic matrices are used for composites inserted into hot structures; thermoplastic resins melt above 200-350°C, and the thermosetting matrices are weakened above 200°C. Some uses require very unusual matrix choices. This is the case for Formula 1 brakes, and the Ariane rocket nozzles, designed with 3D carbon: not only are the fibers carbon, but the binder is carbon too. Compared with a part made completely of carbon, this composite resists much better to crumbling, and can used at temperatures well in excess of 1,000°C.

 

Vinci motor, European Space Agency

The Vinci motor is made for European space agency rockets. Its nozzle (the black cone in the picture), which enables the propulsion, is made of a carbon-carbon composite. Credits: DLR German Aerospace Center.

What are the benefits of composites?

SD: These materials are very light, while offering physical properties that are at least equivalent to those of metallic materials. This benefit is what has won over the transportation industry, since a lighter vehicle consumes less energy. Another benefit of composites is they do not rust. Another feature: we can integrate functions into these materials. For example, we can make a composite more flexible in certain areas by orienting the fibers differently, which can allow sub-assemblies of parts to be replaced by just one part. However, composite resins are often water-sensitive. This is why the aeronautics industry simulates ageing cycles in specific humidity and temperature conditions.

 

What approach is envisaged for recycling composites?

SD: Thermoplastic matrices can be melted. The polymers are then separated from the fibers and each component is processed separately. However, thermosetting matrices lack this advantage, and the composites they form must be recycled in other ways. It is for this reason that researchers, seeking materials with a reduced carbon footprint, are looking to agro-based composites, by using more and more plant fibers. There are even composites that are 100% agro-based, associating bio-sourced polymers with these organic reinforcements. Composite recycling concerns do not yet attract the attention they deserve, but research teams are currently investing in this means of development.

 

Read more on our blog

Agro-based composite materials – a Mines area of expertise

sharing economy

The sharing economy: simplifying exchanges? Not necessarily…

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The groundbreaking nature of the sharing economy raises hope as well as concern among established economic players. It is intriguing and exciting. Yet what lies behind this often poorly defined concept? Godefroy Dang Nguyen, a researcher in economics at Télécom Bretagne, gives us an insight into this phenomenon. He co-authored a MOOC on the subject that will be available online next September.

 

To a certain extent, the sharing, or collaborative, economy is a little like quantum physics: everyone has heard of it, but few really know what it is. First and foremost, it has a dual nature, promoting sharing and solidarity, on the one hand, and facilitating profit-making and financial investment, on the other. This ambiguity is not surprising, since the concept behind the sharing economy is far from straightforward. When we asked Godefroy Dang Nguyen, an economist at Télécom Bretagne, to define it, his reaction said it all: a long pause and an amused sigh, followed by… “Not an easy question.” What makes this concept of the collaborative economy so complex is that it takes on many different forms, and cannot be presented as a uniform set of practices.

 

Wikipedia and open innovation: two methods of collaborative production

First of all, let’s look at collaborative production. “In this case, the big question is ‘who does it benefit’?” says Godefroy Dang Nguyen. This question reveals two different situations. The first concerns production carried out by many operators on behalf of one stakeholder, generally private. “Each individual contributes, at their own level, to building something for a company, for example. This is what happens in what we commonly refer to as open innovation,” explains the researcher. The second situation relates to collaborative production that benefits the community: individuals create for themselves, first and foremost. The classic example is Wikipedia.

Although the second production method seems to be more compatible with the sharing concept, it does have some disadvantages, however, such as the “free rider” phenomenon. “This describes individuals who use the goods produced by the community, but do not personally participate in the production,” the economist explains. To take the Wikipedia example, most users are free riders — readers, but not writers. Though this phenomenon has only a small impact on the online encyclopedia’s sustainability, it is not the case for the majority of other community services, which base their production on the balance maintained with consumption.

 

Collaborative consumption: with or without an intermediary?

The free rider can indeed jeopardize a self-organized structure without an intermediary. In this peer-to-peer model, the participants do not set any profit targets. Therefore, the consumption of goods is not sustainable unless everyone agrees to step into the producer’s shoes from time to time, and contribute to the community, thus ensuring its survival. A rigorous set of shared organizational values and principles must therefore be implemented to enable the project to last. Technology could also help to reinforce sharing communities, with the use of blockchains, for example.

Yet these consumption methods are still not as well known as the systems requiring an intermediary, such as Uber, Airbnb and Blablacar. These intermediaries organize the exchanges, and in this model, the collaborative peer-to-peer situation seen in the first example now becomes commercial. “When we observe what’s happening on the ground, we see that what is being developed is primarily a commercial peer-to-peer situation,” explains Godefroy Dang Nguyen. Does this mean that the collaborative peer-to-peer model cannot be organized? “No,” the economist replies, “but it is very complicated to organize exchanges around any model other than the market system. In general, this ends up leading to the re-creation of an economic system. Some people really believe in this, like Michel Bauwens, who champions this alternative organization of production and trade through the collaborative method.”

 

La Ruche qui dit Oui!

La Ruche qui dit Oui! is an intermediary that offers farmers and producers a digital platform for local distribution networks. Credits: La Ruche qui dit Oui!

 

A new role: the active consumer

What makes the organizational challenge even greater is that the sharing economy is based on a variable that is very hard to understand: the human being. The individual, referred to in this context as the active consumer, plays a dual role. Blablacar is a very good example of this. The service users become both participants, by offering the use of their cars by other individuals, and consumers, who can also benefit from offers proposed by other individuals — if their car breaks down, for example, or if they don’t want to use it.

Yet it is hard to understand the active consumer’s practices. “The big question is, what is motivating the consumer?” asks Godefroy Dang Nguyen. “There is an aspect involving personal quests for savings or for profits to be made, as well as an altruistic aspect, and sometimes a desire for recognition from peers.” And all of these aspects depend on the personality of each individual, as each person takes ownership of the services in different ways.

There’s no magic formula… But some contexts are more faborable than others.

 

Among the masses… The ideal model?

Considering all the differentiating factors in the practices of the sharing economy, is there one model that is more viable than another? Not really, according to Godefroy Dang Nguyen. The researcher believes “there’s no magic formula: there are always risk factors, luck and talent. But some contexts are more favorable than others.”

The success experienced by Uber, Airbnb and Blablacar is not by chance alone. “These stakeholders also have real technical expertise, particularly in the networking algorithms,” the economist adds. Despite the community aspect, these companies are operating in a very hostile environment. Not only is there tough competition in a given sector, with the need to stand out, but they must also make their mark in an environment where new mobile applications and platform could potentially be launched for any activity (boat exchanges, group pet-walking, etc.). To succeed, the service must meet a real need, and find a target audience ready to commit to it.

The sharing economy? Nothing new!

Despite these success factors, more unusual methods also exist, with just as much success — proving there is no ideal model. The leboncoin.fr platform is an excellent example. “It’s a fairly unusual exception: the site does not offer any guarantees, nor is it particularly user-friendly, and yet it is widely used,” observes Godefroy Dang Nguyen. The researcher attributes this to the fact that “leboncoin.fr is more a classified ad site than a true service platform,” which reminds us that digital practices are generally an extension of practices that existed before the Internet.

After all, the sharing economy is a fairly old practice with the idea of “either mutually exchanging services, or mutually sharing tools,” he summarizes. In short, a sharing solution is at the heart of the social life of a local community. “The reason we hear about it a lot today, is that the Internet has multiplied the opportunities offered to individuals,” he adds. This change in scale has led to new intermediaries, who are in turn much bigger. And behind them, a multitude of players are lining up to compete with them.

Read the blog post Digital commons: individual interests to serve a community

 

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Discover the MOOC on “Understanding the sharing economy”

The “Understanding the sharing economy” MOOC was developed by Télécom Bretagne, Télécom École de management and Télécom Saint-Étienne, with La MAIF. It addresses the topics of active consumers, platforms, social changes, and the risks of the collaborative economy.

In addition to the teaching staff, consisting of Godefroy Dang Nguyen, Christine Balagué and Jean Pouly, several experts participated in this MOOC: Anne-Sophie Novel, Philippe Lemoine, Valérie Peugeot, Antonin Léonard and Frédéric Mazzella.

 

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Avec PREVER, tous les résidus sont valorisables en énergie

PREVER: residue turned into energy

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Mines Nantes is home to PREVER – France’s only technological platform that offers a large range of competencies and tools for converting industrial and household waste into energy. It provides customized support for companies wanting to produce combustibles or fuel from miscellaneous residues.

 

As a species, Homo sapiens have a very strange way of disposing of their waste. They dig an enormous hole, put their waste and debris in it, cover it up, then start the process all over again in a nearby location. And there you have it! “Out of sight and out of mind”. Over the past few decades, some individuals from this species have been warning their fellow creatures about the dangers of continuing this practice. They describe its consequences for the sustainability of their habitat and environment, and therefore their own survival. Consequences that could almost make them deny their very identity as humans. Fortunately, solutions are beginning to emerge!

At Mines Nantes, an area of almost 520 m2 is dedicated to a research and analysis platform for energy recovery from residues (PREVER). What is the goal of the scientists working there? To work together with companies to explore new solutions for recycling household and industrial waste and transforming it into energy sources. “This includes any companies that want to use their residues to produce their own energy, and SMEs and start-ups that want to develop a recycling program,” explains Mohand Tazerout, who is in charge of PREVER.

The platform team meets with companies and identifies their needs, whether this involves solving specific problems for very small businesses, or developing large-scale programs for major companies. The researchers then prototype a solution, taking the entire recovery chain into account: from the raw residue to the final product. This residue may be in the form of a synthesis gas, a solid fuel or another fuel. This platform also offers the benefit of working alongside companies from the prototyping to full-scale production stages.

 

A technological solution that’s unique in France

Another advantage is that PREVER has all the machinery required to study the performance of recovery processes. “When we’re working with a liquid fuel, for example, we have engine test units that enable us to study its energy characteristics or its impacts on the environment,” describes Mohand Tazerout. The platform is very well equipped with cutting-edge equipment, including electricity-generating boilers, gas microturbines, hydrothermal liquefaction machinery, etc. “I believe we are the only platform in France to feature all the material for the recovery chain in the same place,” the researcher continues.

In addition to the technical aspect, PREVER also boasts a physico-chemical analysis laboratory, which extends its range of services: atomic spectroscopy, thermogravimetric analysis, octane number measurement, etc. It can also rely on its qualified staff, who are highly qualified for their tasks. As Mohand Tazerout mentions, “The department associated with PREVER includes around ten researchers who work with the companies on the programs, plus technicians and PhD students who are specially recruited for specific projects.”

The reason the platform offers this wide range of energy recovery methods is because it can work with all types of residue. The researcher explains, “We work with all types of waste, from the food industry to household waste, organic, inorganic, liquid and solid waste…” This also includes unusual and atypical waste, such as maritime wood contaminated by oil spills. PREVER seeks to demonstrate that all residues can be converted into energy, and that hiding them in a hole is no longer a solution in our modern day and age.

Read the blog post Vabhyogaz uses our waste to produce hydrogen

 

Mines Alès, Mines Douai, Agro-based composite materials

Agro-based composite materials – a Mines area of expertise

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The materials of the future need to be more than just high-performance. They must also be environmentally friendly: more recyclable and based on renewable resources. This is why scientists and industrialists are taking a closer look at composite materials developed from plant fibers. They represent a major research focus for Institut Mines-Télécom (IMT) schools — especially at Mines Alès and Mines Douai — which participated in the symposium on March 30th on “Materials: realities and new frontiers”.

 

 

Patricia Krawczak is convinced: for certain structures, composite materials developed from plant fibers can now compete with those developed with fiberglass. This researcher from Mines Douai, who led the session on “The opportunities and limits of eco-materials” at the IMT Materials symposium at the end of March, has been working on this topic for around ten years. She has witnessed the emergence and development of these agro-based composites: “In the beginning, it was just plastics reinforced with short lengths of natural fibers (flax, hemp, or cellulose and wood). This produced materials with poor mechanical performance,” she explains. It is only over the past few years that the industrial field has been restructured to develop solutions capable of manufacturing high-performance parts with a rigidity, strength and durability comparable to fiberglass, which currently predominates. “Agro-based composites are no longer used only as cladding components; they can also be used to develop semi-structural parts,” explains Patricia Krawczak. This is the case in transport sectors (automobile, aeronautics, rail, ship building, etc.) and in the building sector.

Among the plants tested for these new uses, flax and hemp stand out from the others, especially in France. They have the advantage of being abundant resources in our country. As Patricia Krawczak reminds us, “the emergence of agro-based materials is rooted in a sustainable development approach.” The use of plant fibers can potentially result in composites that are more easily recycled. The use of local crops therefore enables supply and transport with a low carbon footprint, consistent with this principle of limiting the impact on the environment. In addition to being abundant, these plants also offer benefits of a scientific and technical nature. A great deal of work is being carried out to improve the understanding and mastery of the resulting composite materials.

 

Mines Douai, Mines Alès, Agro-based composite materials

France is the world’s leading producer of textile flax. Credits: BERTFR.

 

Mastering the performance of agro-based composites

At Mines Alès, Anne Bergeret’s team is therefore seeking to identify the parameters that influence the wear properties of plant fiber-based composites, such as mechanical properties, thermal stability, and durability. The manner in which the plant fibers are dispersed within the polymer matrix has proven to be a key parameter. This depends on the fiber’s intrinsic characteristics, such as its chemical composition, surface chemistry, structure, and the application conditions. Another decisive parameter is the quality of the interface between the plant fiber and the polymer matrix. Research carried out at Mines Alès has shown that certain plant fiber treatments, though commonly used, such as caustic soda processing, have an impact on the fiber’s structure, and therefore on its properties and state of dispersion within the matrix. In light of this paradox, Anne Bergeret reminds us of “the need for a full understanding of the fiber’s processing conditions and the application of agro-based composites”.

“If a part needs to conform to a particular functional specification or a specific request, lightening the material at the expense of its strength and rigidity is not a solution”

This a view shared by Patricia Krawczak, whose research work at Mines Douai has also been subject to a compromise between lightening and performance. “If a part needs to conform to a particular functional specification or a specific request, lightening the material at the expense of its strength and rigidity is not a solution. Therefore, we always think in terms of specific properties, in other words, performance/density ratios,” she explains. This partially explains why plant fibers can compete with fiberglass for certain uses, but will probably not rival carbon fiber, which has an indisputably superior mechanical property/density ratio.

 

Integrating the specific characteristics of natural fibers into digital simulation tools

Despite the performance characteristics of plant fibers, such as flax, they are in no position to replace more conventional fibers in all product specifications. To think otherwise would be to ignore the intrinsic characteristics of these fibers. Plants, by their nature, have variable characteristics, due to their growing conditions (seasonality, climate, place of production, etc.). They are also porous, which makes their fibers sensitive to humidity. They also have a low level of tolerance for high temperatures; it would therefore be difficult to associate them with polymer matrices with forming processes that require heating to very high temperatures. But agro-based composites are already highly suitable for use in more favorable conditions, in which their sensitivity to humidity does not present a problem, or by associating them with polymer matrices that can be transformed at lower temperatures. Furthermore, research is underway to remedy these problematic aspects. The goal is to make natural fiber reinforcements water-repellent, or to adapt plastic manufacturing processes to allow for the production of composite parts under gentler conditions.

“We will not be able to compensate for the porous nature of the fibers, and it will be difficult to overcome their variable characteristics due to their natural origin,” Patricia Krawczak points out. “However, we can make sure these specific features are taken into account in the models and simulations, and in this way ensure that designers, processers and users of industrial parts fully understand the behavior of agro-based composites.” The development of the virtual engineering chain for these materials is booming. The same is true for the market growth of these agro-based composites. “Industrialists from different fields of application are open to using them, but will only do so if the simulation tools they use in their design offices are compatible,” explains the researcher. Her team is working on these aspects as well.

 

Turning the weaknesses of the plant fibers into strengths

While in Mines Douai scientists are focusing on modeling in order to better understand the limits of plant fibers, Anne Bergeret and her team at Mines Alès are seeking to turn these limitations into advantages. The plants have low thermal stability (decomposition beginning at 250°C), making them relatively inflammable. However, they have the particular feature of forming a stable carbonaceous residue after decomposition. The combustion of flax-based composites therefore produces this residue on the surface, which has the property of protecting the underlying material and slowing down its deterioration. Anne Bergeret’s team has therefore sought to promote this appearance of charred residue by grafting phosphorous flame-retardants onto the surface of fibers. The results have shown an improvement in the reaction to fire, and should therefore improve the resilience of the composite, whose structure will be less severely damaged.

Whether the aim is to understand the limitations of agro-based composites or to take advantage of them, either way, researchers are dedicated to using biomass and turning it into new useful materials for the industrial sectors seeking innovations — in aeronautics, as well as in electronics and medical equipment. With them, the sectors are being reorganized, through projects like Fiabilin (PIA-PSPC) and Sinfoni (PIA-PSPC), in which Mines Douai has participated, and Enafilia (ADEME) and Hermes (H2020), with the involvement of Mines Alès, involving flax and hemp growers alongside multidisciplinary scientists, plastics manufacturers, and end users. The emergence of these materials is not merely a hope, it is a necessity because, as Anne Bergeret puts it: “In all our studies, we see the need for an integrated, interdisciplinary approach, combining the skills of materials specialists like us with those of farmers, biologists and chemists, for a comprehensive understanding and the optimal use of biomass.”

Read more on the blog What is a composite material?

Find out more about the research in agro-based composites at Mines Douai
Find out more about the use of biomass for materials

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Reminder: What is a composite material?

Just like wattle and daub, made of straw and mud, a composite material is created from a fiber reinforcement and a binder called the matrix. Glass and carbon fibers are currently the most commonly used fibers, but they are facing competition from plant fibers, which facilitate recycling and decrease the material’s environmental impact.

The composite’s matrix is generally a thermoplastic or thermosetting polymer. When it is thermoplastic, the polymer is heated to be liquefied and combined with fibers, then cooled to form the final solid material. A thermosetting polymer is originally liquid and easily incorporates the fibrous reinforcements, but it must then be heated in order to harden and form the final composite material. Polymer matrices are also called organic matrices, but they are not the only matrices that exist. There are also ceramic and metal matrices.

Through the careful combination of fibers and the matrix, composite materials offer unusual mechanical properties, which few other materials can offer. The specifications, which dictate the final target properties based on the future use of the part, are what generally define the choice of fibers (type, content, orientation, cut/continuous/woven/braided, etc.) and of the matrix.[/box]