Scientists learning to control properties of ‘self-healing’ polymers
A project titled ‘Controlling the kinetics of interchain exchange reactions in polytriazoline vitrimers’ is receiving funding from the Russian Science Foundation.
Project lead, Associate Professor Andrey Galukhin, explains the specifics, “Vitrimers are a class of macromolecular compounds that combine the properties of thermoplastic and thermosetting polymers. The network structure of vitrimers is formed by chemically dynamic covalent bonds, which, upon reaching a certain temperature (let’s call it Tv), begin to actively participate in interchain exchange reactions, which allows the polymer network to change its topology. Thus, at temperatures above Tv, vitrimers undergo plastic deformation, reprocessing, shape change, like thermoplastic polymers, while retaining their cross-linked structure, and below Tv, they have all the properties of thermoplastics. In addition, at this temperature there is a ‘healing’ of damage in products made from similar materials.”
He said that within the framework of the project, its participants are searching for new polymeric materials of the type under study, and also find out how to control the kinetics of interchain exchange reactions.
“Although vitrimers are cross-linked polymers, like rubber, they can be recycled. Rubber products cannot. The second feature is that these materials have the ability to self-heal. If, for example, a phone case made of a vitrimer is cracked or scratched, then the defect can be eliminated by simply heating it with a hair dryer,” continues Galukhin.
According to the chemist, the ability of vitrimers to self-heal helps extend the service life of products made from them, reduce maintenance costs, and also increase the safety of structures made from these polymers.
“The studies will allow us to elucidate the mechanism of the interchain exchange reaction in polytriazoline vitrimers. Data will be obtained on the kinetics of polymerization of alkene azides by differential scanning calorimetry, the influence of the structure of monomers on their reactivity, as well as the presence and nature of crosslinking agents in the reaction mixture on the kinetics of polymerization will be evaluated. The results of our research will be of great practical importance, since they will make it possible to achieve progress in the design of smart polymeric materials with the ability to self-heal. Also, the implementation of the project will help determine the optimal conditions for the recycling of vitrimers, which is especially important in the context of the transition to a resource-saving economy,” concludes the interviewee.