In a significant stride towards sustainable construction materials, researchers have unveiled insights into the long-term viability of recycled elastomeric materials, particularly ethylene-propylene-diene monomer (EPDM) rubber. The study, led by Xavier Colom, explores the potential of replacing virgin EPDM with recycled blends in industrial applications, shedding light on how these materials fare under different environmental conditions.
The research, published in the journal *eXPRESS Polymer Letters* (which translates to *Polymer Letters Express*), focuses on the natural aging of EPDM rubber compounds. The team examined two types of samples: conventional EPDM used in roof membranes and EPDM blended with varying amounts of thermomechanically and microwave devulcanized EPDM (EPDMd). These samples were subjected to natural aging in both coastal and mountainous environments, providing a comprehensive understanding of their durability and performance over time.
The findings reveal that mechanical properties of the EPDM blends decline with higher EPDMd content and prolonged outdoor exposure. Notably, the coastal climate proved more aggressive than the mountainous one when the EPDMd content exceeded 40 parts per hundred rubber (phr). “The coastal environment’s higher humidity and salt content accelerate the degradation process, particularly in blends with higher recycled content,” explains Colom. This insight is crucial for industries looking to incorporate recycled materials into their products, especially in regions with harsh environmental conditions.
One of the key discoveries was the influence of zinc stearate (ZnSt2), a byproduct of vulcanization, on the mechanical behavior of the blends. The combined analysis using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), abrasion tests, and thermogravimetric analysis (TGA) provided a detailed understanding of the degradation processes. “The presence of ZnSt2 significantly affects the mechanical properties and degradation rate of the EPDM blends,” notes Colom. This finding could guide future formulations to optimize the use of recycled materials.
The implications for the energy sector are substantial. EPDM rubber is widely used in roof membranes and other construction applications, where durability and resistance to environmental degradation are critical. The study’s findings suggest that while recycled EPDM blends can be viable, their performance depends on the specific environmental conditions and the proportion of recycled content. This knowledge can help manufacturers make informed decisions about material selection and formulation, ensuring long-term performance and sustainability.
As the construction industry increasingly turns to recycled materials to reduce waste and environmental impact, this research provides valuable insights into the practicality and limitations of using recycled EPDM. “Our findings highlight the need for careful consideration of environmental factors and material composition when incorporating recycled elastomers into industrial applications,” says Colom. This research not only advances our understanding of material degradation but also paves the way for more sustainable and durable construction materials in the future.