Generales

By Andrea Carolina Vargas Malagón, Journalist

The continual expansion of the global vehicle fleet each year promotes the demand for tires, which are considered a significant source of pollution from manufacturing to disposal. Researchers and institutions, including UdeA, seek alternatives to minimize their environmental impact. 

Tires used in cars and motorcycles are made from petroleum products. When burned, they release greenhouse gases. In addition, both the manufacturing and use processes also generate emissions of these gases. Photo: Pixabay

Several environmental issues caused by tires worldwide increase the carbon footprint due to the use of fossil fuels and petroleum-derived materials in their production, the contamination of water sources by microplastics, the emission of pollutants post-incineration of tire waste, and the potential proliferation of disease-carrying rodents and insects like yellow fever and dengue fever due to improper disposal at the end of their lifespan.

Henry Colorado, Ph.D. in Materials Science and coordinator of the CCComposites group of the UdeA School of Engineering said, “The fact that many of their components are petroleum derivatives, their large production volume, and their excessive degradation time are some of the factors that make tires a serious problem. It is challenging to recycle them, and it is impossible to utilize them entirely.”  

Slow degradation

World Business Council for Sustainable Development data shows over 1.6 billion tires are produced annually worldwide. Nearly 1 billion tires end their useful life within the same period. However, due to the extensive degradation time of these elements, an accumulation of end-of-life tires is only sometimes properly recycled, reused, or stored, exacerbated by the environmental problem. 

In response to this reality and in a concerted effort to safeguard the planet, ongoing efforts are being made to develop alternatives to mitigate the impact of tires, mainly focusing on their reuse and recycling at the end of their lifespan. At the Universidad de Antioquia, researchers from the CCComposites group at the School of Engineering have successfully developed at least two projects. These initiatives involve transforming tires by mixing them with other substances to create raw materials for new products, such as rubber cement or flexible roof tiles. Both alternatives reduce the environmental impact of end-of-life tires while simultaneously fostering the advancement and fortification of a sustainable economy.  

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“Tires are not easily recyclable because returning them to their original materials is challenging. Instead, you can give them a second life through mechanical processing. This process entails removing the steel, separating the materials, grinding them, and repurposing them for applications. However, this process is not inexpensive, which complicates market dynamics. Therefore, our focus is on making the business model both technically and economically viable while ensuring environmental sustainability,” explained Colorado. 

Recycling is not the only alternative  

 While the environmental benefits of tire recycling are substantial, as they reduce landfill usage and alleviate ecological risks, tire manufacturers are also progressing to enhance the sustainability and eco-friendliness of tires right from the production stage. A prime example is Bridgestone, which recently developed one of the most sustainable tires on the market. Approximately 75% of its components are recyclable and renewable materials. They have been designed mainly for electric vehicles.  

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“The development of these tires includes natural rubber, synthetic rubber derived from recycled plastic, as well as chemicals from recycled rubber and recycled steel,” said Marcela Castaño, a UdeA chemistry graduate with a Ph.D. in Polymer Sciences and the leading researcher in this program's development. Over 15 months, Castaño collaborated with a multidisciplinary team of professionals to deliver the first batch of 200 sustainable tires. 

“This tire contains 37% recycled and 38% renewable materials. It represents another milestone in our journey, enabling us to identify available raw materials, understand the technical associated with their implementation, and assess their impact on tire efficiency and properties,” Castaño explained. 

Contamination by microplastics, perhaps the most problematic   

Friction between tires and the road surface generates “tire and road wear particles,” comprising tiny tire fragments typically ranging between 2.5 and 40 micrometers. These particles are then dispersed by rain and wind, with over 80,000 tons reaching ice-covered areas. Primarily, these particles settle in the soil and find their way into rivers and seas. Due to the use of carbon black pigment in tires, these microplastics exhibit a dark hue, enhancing their capacity to absorb heat. Consequently, their presence in snow- or ice-covered areas accelerates melting and contributes to the global rise in sea level. 

Given this development, Castaño assured that the tires maintain the same quality and performance as conventional tires. “This demonstrates that there is no need to compromise on quality when choosing sustainable products,” said the researcher.