Solubility improvements in aromatic polyimides by macromolecular engineering

Abstract

Polyimides are proved to be an important class of polymers due to their outstanding set of physical and chemical properties. However, this class of polymers suffers from poor processability, which limits their scope of application. This review article deals with approaches that have been undertaken by different researchers to improve the processability of this class of polymers. Mostly, these are synthetic approaches using new diamine and dianhydride monomers that reduce the interchain interaction of the final poyimide by flexibilizing the polymer chain or increasing the fraction free volume. Accordingly, the structural factors that are responsible for better processability are discussed and representative diamine and diahydride structures are tabulated under different categories. Major efforts towards development of soluble polyimides but maintaining excellent mechanical and thermal properties have been done by our group and are also covered in this article.

Design and synthesis of organosoluble and transparent polyimides containing bulky substituents and noncoplanar structures

“…The mechanical properties of these PI films were measured with a AG-I 50 KN, and the size of film sample was about 50 3 5 3 0.05 mm 3 ; these data are listed in Table IV. All of the PI films presented excellent tensile strength, elongation at break, and Young's modulus in the ranges 65.6-94.9 MPa, 9.3-13.7%, and 1.6-2.8 GPa, respectively.…”

“…The contact angle of the polymer film for water was recorded on a JY-PHb contact angle analysis system. The mechanical properties of the films were measured with a AG-I 50 KN, and the size of each film was about 50 3 5 3 0.05 mm 3 …”

Aromatic Hyperbranched Polymers: Synthesis and Application

“…Aromatic polyimides represent an important class of high-performance polymeric materials because of their many outstanding key properties, such as high mechanical strength, high modulus, unusual thermoxidative stability, excellent electrical properties, and superior chemical resistance [126,127]. Hyperbranched polyimides (hb-PIs) show high T g and superior solubility due to their 3D architecture as well as excellent physical and chemical properties.…”

Synthesis and characterization of novel highly soluble and optical transparent polyimides containing tert-butyl and morpholinyl moieties

“…At present, they are extensively used in various fields of microelectronics, optoelectronics, aerospace, automobile, gas separation, polymer electrolyte fuel cells, polymer memories, etc. [1][2][3][4][5]. However, polyimides often present poor solubility in common solvents and have high melting temperature.…”