Excellent thermal and mechanical properties of aromatic polyimides (PIs) make them attractive materials in various fields. PIs is performed using polyamic acid (PAA) precursors due to their limited solubility. However, PAAs can be easily depolymerized by moisture and heat, which can degrade the properties of PIs. Therefore, quality control of PAAs is an important task in researches and industrial applications. Here, we propose a simple, rapid, and novel method to observe the depolymerization of PAAs. The method is based on the principle that, as the molecular weight of the polymer decreases, the solution viscosity decreases, and the viscosity of the solution can be easily and rapidly measured using electrochemistry. We accelerated depolymerization by applying heat to a PAA solution and measured the change in viscosity of the solution through cyclic voltammetry. The proposed method, which also makes it possible to determine the dynamic viscosity of a polymer solution, is presented as a model system to observe state changes in various polymers.
Bibliographical noteFunding Information:
This work was supported by National Research Foundation of Korea , which is funded by the Ministry of Science and ICT ( NRF-2021R1A2C4002069 , NRF-2018R1C1B6008668 ). This research was supported by the Basic Science Research Program of the National Research Foundation of Korea ( NRF ) funded by the Ministry of Education ( 2021R1A6A1A10039823 ). This research was supported by the Institutional Research Program ( SI2252-20 ) of the Korea Research Institute of Chemical Technology ( KRICT ) and by the National Research Foundation ( NRF ) of Korea ( NRF-2021R1A4A1052070 ).
© 2022 Elsevier B.V.
- Electrochemical analysis
- Polyamic acid
- Polymer depolymerization sensing
- Solution viscosity