Fraunhofer Institute for Molecular Biology and Applied Ecology IME
Biomimetischer Synthesekautschuk BISYKA
In the research project "Biomimetic Synthetic Rubber — BISYKA," scientists revealed the secrets of natural rubber. Although synthetic rubber has been produced and continuously optimized since the beginning of the 20th century, it cannot match the unique mechanical properties of natural rubber. Therefore, a consortium of various Fraunhofer institutes took on the challenge of investigating these valuable properties of natural rubber and transferring them to synthetic rubber. The first test tires produced demonstrated a significantly improved performance profile in validated tests, including approximately 30 percent less wear.
One of the core areas of expertise at Fraunhofer IME in Münster is the research of natural rubber biosynthesis in dandelions. Building on this expertise, the researchers set out to investigate the components of natural rubber responsible for its unique properties, such as strain crystallization.
First, they broke down the rubber from dandelions into its components: poly(cis-1,4-isoprene), proteins, and lipids. The lipophilic substances consist mainly of triterpenes/triterpenoids and phospholipids subgroups. These substances may act as emulsifiers for the rubber particles, within which the biosynthesis and storage of the polymer occur. The proteins present are characterized by their membrane activity, meaning they interact with cell membrane components, such as phospholipids. These interactions stabilize the rubber particles.
Analyses of natural rubber samples from which the researchers removed accompanying substances (lipids and proteins) revealed the substances' influence on natural rubber's unique mechanical properties. For instance, strain crystallization is significantly reduced when phospholipids are removed from natural rubber. Next, the scientists added various amounts of individual accompanying substances to synthetic rubber and observed clear effects on strain crystallization. Even adding very small amounts (less than 1%) of certain phospholipids to defined mixtures was effective.
Therefore, in Münster, the experts developed a large-scale manufacturing process for the co-substances. This process enables the production of larger quantities of bio-additive-modified isoprene rubber and allows the consortium to manufacture test tires using the new biomimetic synthetic rubber. In validated performance tests, these tires exhibited approximately 30 percent less abrasion without compromising other quality characteristics. Using “BISYKA” rubber in tire manufacturing could help minimize the release of rubber abrasion into the environment in the future.
With "BISYKA," the Fraunhofer Gesellschaft—by combining expertise in life sciences and engineering—achieved the worldwide first: transferring the unique biological properties of natural rubber to its technical counterpart, synthetic rubber.