SUMMARY
Stage I (year 2022) of High-k-coPI project had as main objective the synthesis of semiaromatic copolyimides containing different polar groups with the aim to be used as film capacitors in energy storage devices. To achieve this objective, two aromatic diamines with polar nitrile groups were synthesized with the role of increasing the dielectric constant of the corresponding copolymers, since higher values are necessary for the intended electronic applications. The structure of these monomers was confirmed by using FTIR and 1H-NMR spectral techniques.
By using as monomers an aromatic dianhydride with polar carbonyl groups and a mixture of two diamines (an aromatic one with polar nitrile groups and meta-phenoxy segments and an aliphatic diamine with polar jeffamine groups selected from a series of 3 diamines) a series of 3 semiaromatic copolyimides with polar groups in a mass ratio of 70:30 between the aromatic and the aliphatic diamine was subsequently prepared. In order to analyze the influence of nitrile groups on the properties of the obtained copolymers, 3 benchmark copolymers were also synthesized by using the same aromatic dianhydride with polar carbonyl groups and a mixture consisting of an aromatic diamine without nitrile groups and the 3 aliphatic diamines with polar jeffamine groups by using the same mass ratio of 70:30. All copolymers were structurally characterized by FTIR and 1H-NMR spectral techniques that fully confirmed the obtaining of the initially designed copolymers.
The optimization of the copolyimide synthesis process was achieved through two parallel activities: changing the molecular mass of the aliphatic jeffamine diamine (by using 3 diamines with molecular masses of 600, 900 and 2000 Da) and, respectively, the use of different mass ratios between the aromatic diamine and the aliphatic diamine. Thus, 2 more series of copolyimides were synthesized, obtaining at the end of the stage a total of 12 semiaromatic copolyimides with polar jeffamine groups with/without nitrile units which will be analyzed from the physico-chemical point of view in the next stage of this project.
Part of the results obtained during the first stage of High-k-coPI project were disseminated in form of 4 presentations at international scientific events that acknowledge the financial support offered by this project.
Results dissemination in international conferences:
1. Flexible films based on semiaromatic copolyimides for energy storage applications
I. Butnaru*, A. P. Chiriac, M. D. Damaceanu
14th International Conference on Physics of Advanced Materials (ICPAM-14), Dubrovnik, Croatia, 8 – 15 septembrie 2022 ( oral presentation -awarded by ICPAM Association)
2. Composite materials based on nitrile-containing polyimide and MWCNTs for energy applications
A.P. Chiriac, I. Butnaru*, M. Asandulesa, M.D. Damaceanu
14th International Conference on Physics of Advanced Materials (ICPAM-14), Dubrovnik, Croatia, 8 – 15 septembrie 2022 (poster presentation)
3. Copolyimides based on aromatic-aliphatic moieties as materials for energy-storage applications
I. Butnaru*, A. P. Chiriac, M. D. Damaceanu
6th International Conference on Chemical Engineering, Innovative Materials and Processes for a Sustainable Development, ICCE-2022 Iasi, 5 – 7 octombrie 2022 (oral presentation)
4. Copolyimides incorporating nitrile and jeffamine moieties for high dielectric constant materials
I. Butnaru*, A. P. Chiriac, M. D. Damaceanu
3-day International Conference on Materials Science (3d-ICOMAS), Verona, Italia, October 25-29, 2022 (oral presentation) | 
