Plant fibers are used to produce auto parts | Energy and science

In August, the State University of São Paulo (Unesp) signed an agreement with Volkswagen do Brasil to develop new composites that include plant fibers in their composition – composites are materials of two or more components, such as glass and metal, with properties superior to those for which they are known. They grew up. The goal is to use this new material in the interior finishing parts of the automaker’s vehicles.

The project is led by agronomist Alcides Lopes Leão and chemist Ivana Cesarino, coordinators of the Laboratory of Bioprocesses and Biotechnology at the Faculty of Agricultural Sciences of Unesp, Botucatu (SP), and will last 18 months. At the end of the period, the multinational company expects to have more sustainable parts, due to the reduced use of plastics of fossil origin in its composition and, above all, lighter and more efficient vehicles from an energy point of view. The main advantage of replacing metal components with plant fibers – less dense materials – is to reduce the weight of the vehicle, and thus reduce fuel consumption. However, there are still some limitations that need to be overcome, such as the low resistance of natural fibers to moisture, susceptibility to fungi and their longevity.

Leão has been studying the use of plant fibers in composite materials since the 1990s, and the current partnership with Volkswagen is the heir to a project funded by FAPESP in 2000 (See Pesquisa FAPESP nº 104). At the time, Leão was researching the potential of curauá fibers (pineapple erect;), a plant native to the Amazon rainforest that he discovered while fishing in the region’s rivers.

The project aroused the interest of Volkswagen, which even produced some auto parts with fibers, and the researcher was invited to give lectures on the subject to company engineers in Brazil and Germany. But the automaker could not find a regular supplier for the curauá and shelved the project. After two decades, Liao was surprised by a new invitation. “I no longer have any contact with anyone from Foulkes. They decided to invest in the production of pieces from vegetable fibers and found me this year by searching the Internet, ”says the researcher.

Now, to determine the best fiber to incorporate into the plastic, four options are being tested: coir, jute, sisal, and bamboo. The issue of supply will influence the decision, which the researcher believes is better balanced. “Because the current project has a global reach, Germany can count on fiber suppliers in many countries,” he says. Initially, the fibers will be fused to the polymer on a macro scale in six pieces that make up the torso of the Polo model. Next, the idea is to work on a nanometer scale. “Incorporating the nanocellulose doubles the resistivity of the composite,” Lau explains.

According to the researcher, natural fibers are already used in various types of vehicles, on a small scale, by some car manufacturers around the world. The biggest consumer is Germany’s Mercedes-Benz, which uses about 30 kilos of fiber per car. At Volkswagen we will start with around 8 kilograms per vehicle. If you think they make 6 million cars a year, it could be a lot,” he says. In these composite materials, the polymer acts as a matrix, responsible for its structure, and the fiber is the stiffening element. Using fiber alone to manufacture auto parts would not provide the resistance that the material needs .

Developing high-performance materials for the automotive industry from regional raw materials is also the goal of a team from the Universities Federal Paraíba (UFPB) and Campina Grande (UFCG) and the Fraunhofer Institute for Manufacturing Technology and Advanced Materials, based in Bremen, Germany. The project is funded by the Paraíba State Research Support Foundation (Fapesq) and the German Ministry of Education and Research. In Brazil, it is being coordinated by Materials Engineer Renate Willen, from the UFPB Materials Engineering Department.

The researchers began their project by working with sisal fibers in Brazil and flax in Germany. “The best properties are obtained with flax, which molds better like a fabric to be fused into the composite by pressing. The goal is to use the material on the inside of the door, which was chosen because of the high demand from the industry and because it is a less complex structure,” explains Wellen.

As in the Unesp project with Volkswagen, the partnership between the Brazilians and the Germans was born out of internet searches. This time it was the Brazilian side that took the initiative. Committed to developing projects in the field of plant fibers and aware of Germany’s growing interest in green technology, in 2015 a UFPB researcher made contacts with several German universities and research institutes.

These contacts resulted in his postdoctoral work at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials in Bremen and the current project. For Willen, UFPB’s General Research Coordinator, sharing experiences between teams is one of the most important aspects of the agreement. There has been an improvement in student training. We have two team members with PhDs in Germany.”

The new natural fiber reinforced polymer is being completed and the prototype of the auto part made with it was presented in October at K-Show 2022, the largest international event in the plastics and rubber industry, which was held in Düsseldorf, Germany. There is indeed potential for the development of a new composite material, possibly made from coir fibres, an abundant raw material in Brazil. “The Germans are interested in continuing the partnership,” Willen says.

From soy cars to fiber cement

The attempt to use natural fibers in the automotive sector has been going on for a long time. In 1930, Henry Ford, a pioneer in the production of automobile series, invented a material called bioplastic. Its exact composition is uncertain, as no record of the formula is kept, but in 1941 the prototype produced with the substance became known as the Otto Soybean, the Soybean Car. However, the new car never entered the factory production line.

According to information from the Benson Ford Research Center, a research institute run by the Henry Ford Museum, the outbreak of World War II (1939-1945) suspended all automobile production in the United States. As a result, the soybean car experiment did not develop. After that, the company’s efforts were directed towards compensating for the losses caused by the war and the bioplastic car fell into oblivion.

For chemical engineer Sandro Amico, coordinator of the composites and nanomaterials group at the Federal University of Rio Grande do Sul (UFRGS), another factor contributing to the industry’s lack of interest was the advent of glass and carbon fibers in the 1930s to 1950s. He shows that synthetic fibers have advantages such as higher stiffness and greater mechanical resistance to chemical and environmental attacks — while natural fibers were vulnerable to moisture, for example. Today, this problem can be circumvented by processing the fibers or by using additives in the combined composition and taking care of Environment He brought natural fibers back into the industrial scene.

Amico has been working with different types of fibers for over two decades. “Today there are many examples of applications that did not exist five years ago and others that have increased in size,” the professor testifies. As an example, he cites the plastic wood known as WPC (wood-polymer composite), which appeared in the 1960s and consisted of sawdust and a thermoplastic polymeric resin, such as PVC or polyethylene. “It was a huge commercial success in North America,” he says.

At the Technological Federal University of Paraná (UTFPR), students of forestry engineer Ugo Leandro Bellini, from the Department of Industrial Design and Graduate Program in Urban Environmental Sustainability, are researching how to make more sustainable products, such as lighting fixtures and eyeglasses. One of them attracted the interest of a local company. “In a concluding course work paper, a frame for eyeglasses was constructed from a composite of cane particles dyed with a natural dye, saffron, and bonded with a polyurethane resin to castor beans,” Belini accounts.

According to a market analysis published in 2020 by North American consulting firm Grand View Research, the natural fiber composites market is growing worldwide. The company estimates that the sector will reach 10.9 billion US dollars by 2024. The most widely used area for this material is civil construction, which accounts for more than half of the demand. Outside, the most widely consumed material is WPC plastic wood, used for floors, floors, door and window frames, and coverings. The fibers are also used in concrete structural elements.

In Brazil, fiber cement tiles made from a mixture of cement and asbestos, a mineral fiber known to be carcinogenic, were banned in 2017, giving way to new compounds of plant origin. Civil engineer Holmer Savastano Jr., of the Faculty of Animal Sciences and Food Engineering of the University of São Paulo (FZEA-USP), responsible for the development of fiber cement roof tiles made of cellulose pulp patented in 2012, leads a project for the production of reinforced cement with a tertiary structure Dimensional (3D) jute and violet.

According to a researcher who has been studying since the 1990s the use of plant fibers in the production of tiles (See Pesquisa FAPESP no 98), jute and violet textile screens adjacent and perpendicularly connected to each other form a structure that provides lightness with greater mechanical and chemical resistance than the patented product of 10 years ago. The project receives support from FAPESP and the Foundation for Research Support of the State of Amazonas (Fapeam), through a scientific collaboration agreement that brings together researchers from USP and the Federal University of Amazonas (Ufam).

“The Amazonas team has experience with polymer matrices and knots in fiber cement layers. There is complementarity and exchange of rich experience,” says Savastano. With the ban on the use of asbestos, he sees good prospects for the commercialization of new panels. “Since there is no longer any risk of toxicity, it has been Also considering the use of fiber cement for internal uses, in room dividers, linings and floors, which may increase the demand for the new product in the construction sector.”

This text was originally published by Pesquisa FAPESP under a Creative Commons license CC-BY-NC-ND. Read the original text here.