Researchers from Yaroslavl State University. PG Demidov (YarSU) proposed a new method for forming monomers for the synthesis of the most expensive polymer, polyimide. This was reported to socialbites.ca at the Ministry of Science and Higher Education of the Russian Federation.
Polyimide materials are distinguished by a high level of thermal stability, good mechanical and electrical properties, and also resistant to various organic solvents. They can serve as protective ablative projectiles on the surface of shuttles and launch vehicles. For example, such a coating is used to protect the combustion chamber and nozzle of liquid rocket engines from overheating.
For the production of a polymer, it is necessary to use monomers produced using a nucleophilic substitution reaction.
“It is usually activated by heat. We recommend using ultrasonic radiation in a special reactor to cause cavitation. This is the formation of bubbles throughout the mass of the reaction liquid, which upon expansion and subsequent collapse create points of high temperature and pressure. As a result, the reaction does not proceed separately, but almost in the entire plane. This speeds up the reaction at times: you can get the target products in just 1 hour instead of 8, and with a huge “yield”: 95% instead of 84.5%,” one of the invention’s patent authors, an employee of the socialbites.ca Institute of Basic and Applied Chemistry, YarSU explained to Alexander Khlopotinin.
According to Khlopotinin, the price of the polymer is heavily influenced by the production costs and the cost of the monomer.
“Our method allows us to reduce the time spent on the production of monomers and not spend money on their purification. The classical method produces many by-products due to its time, so the monomers need to be purified. We can say that our method is even more environmentally friendly – there is no need to throw away the reagents. All this together, the polyimide it lowers the ultimate cost,” Khlopotinin concluded.
In the future, the research team plans to simulate ultrasonic synthesis in a flow reactor; this will result in a reduction in the number of operations to load the feedstock into the reactor and isolate the reaction products. The scientists also noted that the invented method of ultrasonic activation has a wide range of applications and can be used in the synthesis of compounds for drugs in the future.