Researchers from Yaroslavl State University have introduced a novel approach to forming monomers used in the production of polyimide, one of the most expensive polymers on the market. This development was reported to socialbites.ca by representatives of the Ministry of Science and Higher Education of the Russian Federation.
Polyimide materials stand out for their remarkable thermal stability, strong mechanical and electrical properties, and resilience against a wide range of organic solvents. They find use in protective ablative coatings on the surfaces of shuttles and launch vehicles. A notable application is the protection of the combustion chamber and nozzles of liquid rocket engines from overheating thanks to such coatings.
The synthesis of this polymer relies on monomers produced through a nucleophilic substitution reaction.
The process is typically driven by heat. The researchers recommend employing ultrasonic radiation within a specialized reactor to induce cavitation. Cavitation refers to the formation of bubbles throughout the reaction medium, and when these bubbles expand and collapse, they generate zones of high temperature and pressure. As a result, the reaction can proceed across the entire liquid phase rather than at isolated points, accelerating the process dramatically. Target products can be obtained in about one hour instead of eight, with yields reaching around 95 percent rather than about 84.5 percent, according to the device’s patent author and a member of the Institute of Basic and Applied Chemistry at Yaroslavl State University, who spoke to Alexander Khlopotinin.
Experts note that the price of polyimide is significantly affected by production costs and the cost of the monomer itself.
The new method enables faster monomer production and reduces or eliminates purification steps, since fewer by-products are formed due to the shortened reaction time. This efficiency translates into lower overall costs and reduces waste, making the process more environmentally friendly. These improvements collectively contribute to a lower final price for polyimide.
Looking ahead, the research team intends to model ultrasonic synthesis in a flow reactor. This approach would streamline the workflow by reducing the number of steps required to feed materials into the reactor and to isolate the reaction products. The researchers also highlighted the broader potential of ultrasonic activation, suggesting that the technique may find applications in synthesizing drug-related compounds in the future, expanding its relevance beyond polyimides.