Design, Synthesis And Properties Of Novel Soluble High-temperature Resistant Polyamides Containing Xanthene Structures

In this dissertation, the resent progress on the study of aromatic polyamide was investigated. The main contents were described as follow.1. 9,9-Bis(4-hydroxyphenyl)xanthene (BHPX) was synthesized in 82% yield 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.2. Substitution reaction of 9, 9-bis(4-hydroxyphenyl)xanthene with 4-nitrochlorobenzene formed 9, 9-bis(4-nitrylphenoxyphenyl)xanthene in 74 % yield, which was reducted in C2H5OH in the presence of palladium carbon catalyst to give 9, 9-bis(4-aminophenoxyphenyl)xanthene. The overall yield of the two-step reaction was 79.0 %.3. Substitution reaction of 9, 9-bis(4-hydroxyphenyl)xanthene (1) with 4-fluorobenzonitrile (2) formed 9, 9-bis(4-cyanophenoxyphenyl)xanthene (3) in 88.7 % yield, which was hydrolyzed in C2H5OH in the presence of KOH to give 9, 9-bis(4-carboxyphenoxyphenyl)xanthene (4), followed by treatment with sulfur oxychloride to yield polymerization-grade monomer 9, 9-bis(4-chloroformylphenoxyphenyl)xanthene (4). The overall yield of the three-step reaction for (4) was 73.0 %.4. Five kinds of novel polyamides containing xanthene structures in main chain were synthesis from 9, 9-bis(4-aminophenoxyphenyl)xanthene with terephthalyl chloride (TPC), isophthalyl chloride (IPC) 2-(4-trifluoromethylphenoxy)terephthalylchloride, 4,4'-bis(3-chloroformylphenoxy)diphenylsulfone,1,4-bis(4-chloroformylphenoxyphenyl)benzene by low temperature solution polycondensation under N2 atmosphere, respectively. The prepared polyamides containing xanthene structures with inherent viscosities of 0.73-1.25 dL/g exhibit excellent heat-resistance. The glass transition temperatures (Tg's) of these polymers were ranged from 223 oC to 289 oC. The onset temperature taken at 5 % weight loss of these polymers in nitrogen was all over 440 oC. These polymers with tensile strength of 83.3-98.5 MPa, elongation at break of 13.0-16.8 % and tensile modulus of 2.84-3.34 GPa. These polymers were soluble in strongly polar organic aprotogenic solvents such as DMF, DMSO and NMP at room temperature.5. A series of novel copolymers containing xanthene structures in main chain with high molecular weight were synthesized from 9, 9-bis(4-aminophenoxyphenyl)xanthene, TPC and p-phenylenediamine by low temperature solution polycondensation under N2 atmosphere, respectively. The copolymers have been characterized by FT-IR, DSC, TG, etc. The results showed that these new copolymers exhibited excellent heat-resistance, Tg's of the copolyamides were between 303.6 oC and 329.8 oC. The onset temperatures taken at 5 % weight loss of the in nitrogen were in the range of 504 oC-536 oC. The polymers were soluble in concentrated H2SO4, NMP and DMSO at room temperature.6. A series of novel copolymers containing xanthene structures in main chain with high molecular weight were synthesized from 9, 9-bis(4 chloroformylphenoxyphenyl)xanthene, TPC and p-phenylenediamine by low temperature solution polycondensation under N2 atmosphere, respectively. The copolymers have been also characterized by FT-IR, DSC, TG, etc. The results showed that these new copolymers also exhibit excellent heat-resistance, high Tg ranging from 252 oC to 280 oC. The onset temperatures taken at 5 % weight loss of the copolyamides in nitrogen were in range of 493 oC-537 oC. The polymers were soluble in concentrated H2SO4, NMP and DMSO at room temperature.