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

2,2,'3,3' -Biphenyltetracarboxylic dianhydride (2,2,'3,3'-BPDA) was prepare d by a coupling reaction of dimethyl 3-iodophthalate. The X-ray single-crys tal structure determination showed that this dianhydride had a bent and non copolanar structure, presenting a striking contrast to its isomer, 3,3,'4,4 '-BPDA. This dianhydride was reacted with aromatic diamines in a polar apro tic solvent such as N,N-dimethylacetamide (DMAc) to form polyamic acid inte rmediates, which imidized chemically to polyimides with inherent viscositie s 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 transitio n temperatures above 283 degrees C. Thermogravimetric analyses indicated th at these polyimides were fairly stable up to 500 degrees C, and the 5% weig ht loss temperatures were recorded in the range of 534-583 degrees C in nit rogen atmosphere and 537-561 degrees C in air atmosphere. All polyimides we re amorphous according to X-ray determination. (C) 1999 John Wiley & Sons, Inc.