Macromol. Rapid Commun. 2001, 22, 1481–1484 1481 Synthesis and Characterization of a Highly Soluble Aromatic Polyimide from 4,49-Methylenebis(2-tert- butylaniline) Wei Huang, 1 Deyue Yan,* 1 Qinghua Lu 2 1 College of Chemistry and Chemical Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People’s Republic of China E-mail: dyyan@mail.sjtu.edu.cn 2 Analytic and Testing Center, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, People’s Republic of China Keywords: one-pot methods; polycondensation; polyimides; solution properties; tert-butyl groups; Introduction Aromatic polyimides are widely used in advanced tech- nology areas [1] because of their excellent thermal stabi- lity, chemical resistance, outstanding mechanical and electronic properties. In general, it is difficult to process aromatic polyimides because of their poor solubility in organic solvents and high melting temperature in fully imidized form. Therefore, the processing is usually car- ried out with a poly(amic acid) intermediate, which then can be converted into the polyimide via rigorous thermal treatment or chemical treatment. However, this process has some inherent problems, such as the emission of vola- tile byproducts (e.g., H 2 O) and the storage instability of poly(amic acid). [2] In order to overcome these problems, a lot of research work has been reported on the improvement of the solubi- lity and processability of polyimides in fully imidized form without a deterioration of their perfect properties. Several approaches toward soluble polyimides, including the introduction of flexible linkages, [3] asymmetric units, [4] or bulky groups [5–7] into the backbone have been developed during the last decade. On the other hand, some authors [8–13] have demonstrated that introducing a tert-butyl-substituted monomer into the backbone of sev- eral aromatic polymers could improve the solubility and processability without causing the unacceptable loss of thermal properties. Pyromellitic dianhydride (PMDA) has been widely used to synthesize polyimides. But most aromatic polyimides made from PMDA are insoluble or have poor solubility in organic solvents, depending on the structure of the dia- mine used, because PMDA is the smallest and most rigid Communication: 4,49-Methylenebis(2-tert-butylaniline) was synthesized and reacted with pyromellitic dianhy- dride to produce a polyimide that showed excellent solu- bility in conventional organic solvents. Solutions of this polyimide could be cast into transparent, flexible and tough films. The number-average molecular weight, as determined by means of gel permeation chromatography, was 8.9 6 10 4 g/mol and the polydispersity index was 1.97. The glass transition temperature was found to be 217 8C. The polyimide did not show appreciable decom- position up to 500 8C under a nitrogen atmosphere. Macromol. Rapid Commun. 2001, 22, No. 18 i WILEY-VCH Verlag GmbH, D-69451 Weinheim 2001 1022-1336/2001/1812–1481$17.50+.50/0 UV spectrum of the polyimide film based on PMDA and MBTBA.