Water as Solvent in Polyimide Synthesis II: Processable Aromatic Polyimides

Abstract

Some representative thermal, chemical and mechanical characteristics of ‘commercial type’ polyimides are presented in this second paper in a series on using water as solvent in polyimide synthesis. The commercial types of polyimide that have been produced in this study are closely related to Kapton, Upilex R®, Upilex S®, Avimid N® and PMR-15. The chemical characterization of these materials using both nuclear magnetic resonance and Fourier Transform infrared indicate very pure and fully imidized products. The thermal and mechanical data from techniques such as thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical thermal analysis reveal properties that are at least, equivalent to their commercial counterparts. Some improvement in processability is noted in pure materials, mixtures and chemically modified analogues of these well known polyimides. In addition this highly efficient one-pot method potentially provides economic advantages through low solvent cost and environmental impact benefits.

Microwave‐Assisted Aqueous Polyimidization Using High‐Throughput Techniques

“…In similar previous studies, we have used a Parr pressure reactor for this process. [5,9] Using the Biotage 1 reactor and high-throughput characterization techniques, this entire process was completed in a few weeks by one person. Table 1 contains the data obtained for the first optimization phase using 4,4 0 -ODA with 6-FDA.…”

“…[4] The use of water under pressure as solvent for the synthesis of a wide variety of polyimides from amine-carboxylic acid salts has been studied by our group for a number of years and has shown to have significant advantages for many of the commercially important polyimide types due to the reduced solvent costs and minimized environmental problems of the method. [5][6][7][8][9][10] The utility of water-based synthesis has recently been further highlighted with the promotion of an ''on water'' synthetic protocol in small molecule synthesis. [11] The aqueous polyimide synthetic method has another notable feature in that it is a one-step method and does not proceed via an isolable polyamic acid intermediate.…”

Geomimetics and Extreme Biomimetics Inspired by Hydrothermal Systems—What Can We Learn from Nature for Materials Synthesis?

“…In 2003, Chiefari et al reported that the organic polymers, polyimides, could be synthesized in HTW [69,70,71]. Polyimides (PIs) are condensation polymers, i.e., they are obtained by the elimination of a low-molecular weight byproduct (here normalH2O) upon each monomer addition step.…”

Recent development of polyimides: Synthesis, processing, and application in gas separation

“…Later on, the group prepared other polymers with structures similar to Kapton, Upilex, Avimid N, and PMR-15. 56 More recently, Cao et al examined the molecular weight, polydispersity, thermal properties, and mechanical strength of polymers prepared in water and DMAc. 57 They found equivalent physical properties for polymers synthesized in aqueous and organic solvents, demonstrating that water is a viable solvent option for safe, healthy, and inexpensive PI synthesis.…”