Synthesis And Characterization Of Novel Polyimides Containing Xanthene Groups

In this dissertation, the recent progress on the study of polyimides was first investigated. Second, the novel polyimides containing xanthene structure were developed. The main contents were described as follow.1. Bis(4-hydroxyphenyl)xanthene (BHPX) was synthesized by reaction of xanthone with thionyl chloride, affording intermediate 9,9-dichloroxanthene, followed by treatment with phenol in refluxing xylene in a one-pot, two-step synthetic procedure. By improving method of synthesis, the yield of product is above 85%.2. Substitution reaction of 9,9-bis(4-hydroxyphenyl)xanthene with 4-nitrochloro- benzene formed 9,9-bis(4-nitrylphenoxyphenyl)xanthene, which was reducted in C₂H₅OH in the presence of palladium carbon catalyst to give 9,9-bis(4-amino- phenoxyphenyl)xanthene.3. The polyimides were synthesized of 9,9-bis(4-aminophenoxyphenyl)xanthene and ODA and pyromellitic dianhydride , by two-step method. The polymers showed good thermal stability and mechanical properties. And this paper also discussed the influence on properties of polyimides obtained by different methods.4. 9,9-bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]xanthene(BTFAPX) was from the reaction of 9,9-bis[4-(2-trifluoromethyl-4-nitrylphenoxy)phenyl]xanthene in C₂H₅OH in the presence of palladium carbon catalyst.5. The polyimides containing fluorine were prepared from copolymerization of 9,9-bis[4-(2-trifluoromethyl-4-aminophenoxy)phenyl]xanthene (BTFAPX) and ODA and biphenyltetracarboxylic dianhydride in m-cresol by one-step method. Copolymerization can draw bulky xanthene and trifluoromethyl pendants into molecular chain of polyimides to improve polymers'solubility. The copolymers were readily soluble in many solvents, such as N,N-dimethylformamide(DMF), pyridine tetrahydrofuran(THF) and so on.