Synthesis and properties of aromatic polyimides derived from 2,2,?3,3?-biphenyltetracarboxylic dianhydride

Abstract

2,2,′3,3′-Biphenyltetracarboxylic dianhydride (2,2,′3,3′-BPDA) was prepared by a coupling reaction of dimethyl 3-iodophthalate. The X-ray single-crystal structure determination showed that this dianhydride had a bent and noncopolanar structure, presenting a striking contrast to its isomer, 3,3,′4,4′-BPDA. This dianhydride was reacted with aromatic diamines in a polar aprotic solvent such as N,N-dimethylacetamide (DMAc) to form polyamic acid intermediates, which imidized chemically to polyimides with inherent viscosities of 0.34–0.55 dL/g, depending on the diamine used. The polyimides from 2,2,′3,3′-BPDA exhibited a good solubility and were dissolved in polar aprotic solvents and polychlorocarbons. These polyimides have high glass transition temperatures above 283°C. Thermogravimetric analyses indicated that these polyimides were fairly stable up to 500°C, and the 5% weight loss temperatures were recorded in the range of 534–583°C in nitrogen atmosphere and 537–561°C in air atmosphere. All polyimides were amorphous according to X-ray determination. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1425–1433, 1999