Devulkanointia

Devulkanointia is a process aimed at reversing vulcanization, a chemical process that strengthens rubber by forming cross-links between polymer chains. Vulcanization, typically achieved by heating rubber with sulfur, makes the material more durable, elastic, and resistant to temperature changes. However, it also makes the rubber thermosetting, meaning it cannot be easily melted and reshaped, and it is difficult to recycle.

The primary goal of devulkanointia is to break these sulfur cross-links, returning the rubber to a more plastic or thermoplastic state. This allows the rubber to be reprocessed, remolded, and incorporated into new rubber products, thereby promoting circular economy principles and reducing waste. Devulkanointia is particularly important for the recycling of end-of-life rubber products, such as tires.

Various methods are employed for devulkanointia, each with its own advantages and limitations. These include thermal methods that use high temperatures, chemical methods that employ specific reagents to break sulfur bonds, mechanical methods that use shear forces, and microwave or ultrasonic treatments. Often, a combination of these techniques is used to achieve efficient devulkanization. The effectiveness of devulkanization is often measured by the degree of desulfurization and the restoration of the rubber's processability and mechanical properties. While promising for waste reduction, challenges remain in achieving complete devulkanization without degrading the rubber polymers and in making the process economically viable on an industrial scale.