Synthesis and Characterization of Soluble Copolyimides Containing Chalcone and Phosphine Oxide Moieties in the Main Chain Wei Wang, 1 Qunrong Wu, 2 Liqin Ding, 1 Zhilan Yang, 1 Aiqing Zhang 1 1 Hubei Key Laboratory for Catalysis and Materials Science, College of Chemistry and Materials Science, South-Central University for Nationalities, Wuhan 430074, People’s Republic of China 2 Department of Biotechnology, Wuhan Bioengineering Institute, Wuhan 430415, People’s Republic of China Received 27 March 2007; accepted 8 May 2007 DOI 10.1002/app.26961 Published online 24 September 2007 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The functional diamines 3,3 0 -diaminochal- cone and bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide were successfully prepared by simple and convenient procedures with short reaction times, and the overall yields were 78 and 70%, respectively. Copolyimides prepared from 3,3 0 -diaminochalcone, bis(3-aminophenyl)- 3,5-bis(trifluoromethyl)phenyl phosphine oxide, and 4,4 0 - (hexafluoroisopropylidene)diphthalic anhydride exhibited excellent solubility in several organic solvents, such as di- methyl sulfoxide, N,N-dimethylformamide, N-methyl pyr- rolidone, tetrahydrofuran, and acetone. They also showed very good thermal stability even up to 4508C for 5% weight loss (by thermogravimetric analysis) in nitrogen and a high glass-transition temperature up to 2748C (by differential scanning calorimetry) in nitrogen. The copolymers’ adhe- sive and photoreactive properties were also investigated, and it was confirmed that the copolyimide containing chal- cone and phosphine oxide moieties in the main chain had good adhesiveness and photoreactivity. Ó 2007 Wiley Peri- odicals, Inc. J Appl Polym Sci 107: 593–598, 2008 Key words: adhesion; copolymerization; polyimides INTRODUCTION Polyimides are a class of functional polymers with many desirable characteristics that have been used in many high-technology areas, such as aviation, spaceflight, electronics, composite materials, and separation membranes. Photosensitive polyimides, compared with nonphotosensitive polyimides, sim- plify greatly the complex, multistep processing required in photolithography processes. 1 Polymers containing chalcone moieties have been widely stud- ied and applied 2–6 because they have high sensitivity to ultraviolet (UV) radiation and good chemical sta- bility with lower shrinkage. However, because of these photosensitive groups, the polymers have low adhesion to metal substrates when they are used in the microelectronics industry. On the other hand, phosphine oxide moieties can improve adhesion properties. Polymers containing phosphine oxide show excellent adhesion characteristics and thermal stability. 7–11 Hence, we have combined phosphine oxide and chalcone moieties to impart good adhe- sion and photosensitivity properties to polyimides. In this work, the diamine monomers 3,3 0 -diamino- chalcone (mDAC) and bis(3-aminophenyl)-3,5-bis(tri- fluoromethyl)phenyl phosphine oxide (mDA6FPPO) were prepared by simple and convenient procedures with short reaction times and high yields. Soluble copolyimides containing chalcone and phosphine ox- ide moieties in the main chain were synthesized through the copolymerization of mDAC, mDA6FPPO, and 4,4 0 -(hexafluoroisopropylidene)diphthalic anhy- dride (6FDA). The structures and properties of the resulting copolymers were also examined. EXPERIMENTAL Materials and instruments 3-Nitroacetophenone and 3-nitrobenzaldehyde were used as received from Fluka (Buchs, Switzerland); 6FDA, diphenylphosphinic chloride, and 3,5-bis (trifluoromethyl)bromobenzene were obtained from Aldrich (Lyon, France) without further purification. Potassium carbonate, magnesium powder (98.5%), and hydrazine hydration (85%) were obtained from China Medicine (Group) Shanghai Chemical Reagent Corp. (Shanghai, China). Pyridine, tetrahydrofuran, and N,N-dimethylformamide were purified by distil- lation under reduced pressure after being dried over Correspondence to: A. Zhang (aiqingzhang_2000@tom.com). Contract grant sponsor: National Natural Science Foun- dation of China; contract grant number: 50373052. Contract grant sponsor: Natural Science Foundation of Hubei Province; contract grant number: 2001ABA009. Journal of Applied Polymer Science, Vol. 107, 593–598 (2008) V V C 2007 Wiley Periodicals, Inc.