Welcome to this week’s edition of Elkay Silicones insights—your go-to source for cutting-edge knowledge and innovation in the world of silicones! Today we start to explore the world of sustainable silicones—a groundbreaking area in technology, consumer products, and environmental responsibility.
What Are Silicones?
Silicones are synthetic polymers made from silicon, oxygen, carbon, and hydrogen. Chemically, they’re known as polysiloxanes, with a backbone of alternating silicon (Si) and oxygen (O) atoms. Known for their exceptional versatility, silicones combine the best properties of plastics and rubbers—such as durability, flexibility, heat resistance, and water repellence. Unlike conventional plastics, silicones remain stable and can endure extreme temperatures. This makes them ideal for a wide range of applications, including kitchenware, medical devices, electronics, and renewable energy systems. Their unique molecular structure allows for customization, whether biocompatibility for implants or resistance to weathering for outdoor applications.
About half of all silicones are in the form of silicone rubber. Let’s have a look at how silicone rubbers compare to petroleum based and natural rubber:
Unlike traditional materials, silicone can be repurposed with minimal waste, supporting the creation of reusable products. Its resilience and long lifespan contribute to a more sustainable approach, reducing the need for constant replacements and lessening environmental impact.
What Makes Silicones Sustainable?
Recycling silicone rubber is possible due to their unique polymer structure and reversible chemical bonds:
- Chemical Depolymerization and Repolymerization: Silicone polymers can be chemically broken down into their building blocks; siloxane monomers and silicone oils through thermal or catalytic depolymerization. These recovered monomers can be purified and repolymerized to create new silicone materials, reducing the need for virgin raw materials.
- Mechanical Processing: In some cases, used silicone products (like sealants or rubber components) can be mechanically treated and blended into new silicone formulations to enhance durability without chemical breakdown.
Additionally, silicone products can enhance the durability of a wide range of products in building materials, coatings, consumer products and textiles amongst others. We will explore this area in a future newsletter.
Applications:
Recycled silicone oils are the most basic output of chemical recycling, obtained through chemical depolymerization of silicone waste, and have a wide range of applications across multiple industries. Here’s where it is commonly used:
Industrial Lubricants & Coatings: Used as a high-performance lubricant in machinery, automotive parts, and industrial equipment due to its thermal stability and low friction. Acts as a protective coating for electrical components, cables, and aerospace materials.
Automotive & Aerospace: Used in heat-resistant lubricants and greases for engines, bearings, and brake systems.
Construction & Sealants: Blended into reprocessed silicone sealants and adhesives, reducing dependency on virgin materials. Used in waterproofing agents for concrete, tiles, and glass coatings.
Besides silicone oil, today’s advancements have allowed for making many silicone oil derivatives out of sustainable silicone feedstock.
The Road Ahead
Despite the promising benefits, challenges remain in the path of sustainable silicones. The wide range of a feedstock, mitigating costs, and raising awareness are all critical factors to making them more accessible and mainstream. However, as demand for eco-friendly solutions continues to rise, the future of sustainable silicones is bright, with potential to transform industries while protecting the environment.