Synthesis And Properties Of Novel Aromatic Polyamides,Poly(Aryl Ether Ketone)s,Polyesters And Poly(Ester-amide)s Containing Trifluoromethyl Pendant

In this dissertation, the recent progress on the study of poly(aryl ethe rketone)s, polyesters and polyamides were investigated. This paper was mainly composed of six parts as follow.1. 2-(4-trifluoromethylphenoxy)paradimethylbenzene(TFDMB) was prepared in three-step reaction of condensation, oxidation and acylation using 2, 5-dimethylphenol and 1-chloro-4-trifluoromethyl benzene as original materials in dimethyl sulfoxide(DMSO) in the presence of KOH or K2CO3. The optimum reaction condition was obtained as follows: 1-chloro-4-trifluoromethyl benzene/2, 5-dimethyl- phenol 1:1.2 (mol), reaction temperature 140-190 oC, reaction time 8 h. The yield of TFDMB reached 93.7 %. TFDMB was subsequently oxidated into key intermediate, 2-(4-trifluoromethylphenoxy)paraphthalic acid(TFTPA) with 75% yield in the presence of KMnO4 in aqueous solution of pyridine and sodium hydroxide in two step, respectively. And then reaction of TFTPA with sulfur oxychloride yielded polymerization-grade monomer 2-(4-trifluoromethylphenoxy)-terephthalyl chloride (TFTPC) in 92 % yields. The overall yield of the three-step reaction for TFTPC was 64.6 %.2. 2-(4-trifluoromethylphenoxy)-1, 4-bis(4-nitrophenyl)phthalate was synthesized by the condensation of 2-(4-trifluoromethylphenoxy)terephthalyl chloride with 4-nitrophenol. Benzyltriethylammonium chloride (BTEAC) was used as a phase transfer catalyst and sodium hydroxide as an acid acceptor. The low temperature was needed to prevent the hydrolysis of ester groups under alkaline condition and the evaporation of dichloromethane. For the reduction in the present work, the dinitro compound was catalytically hydrogenated with Pd/C in the atmosphere of hydrogen. The product 2-(4-trifluoromethylphenoxy)-1, 4-bis(4-aminophenyl)phthalate was confirmed by IR and 1H NMR analysis. The overall yield of the two-step reaction for diamino compound was 76.6 %.3. A series of poly(aryl ether ketone)s containing xanthene pendant and trifluoromethyl substituents were prepared by the nucleophilic substitution reaction of 1, 4- bis(4-fluorobenzoyl)benzene with varying mole proportions of hexafluorobisphenol A and 9, 9-bis(4-hydroxyphenyl)xanthene using sulfolane solvent. The structure of these polymers have been supported by infra-red and nuclear magnetic resonance spectral data. The inherent viscosities of these polymers were in the range 1.01–1.59 dL/g. These polymers were soluble in organic solvents such as dichloromethane,chloroform,tetrahydrofuran,pyridine,N, N-dimethylformamide,N, N-dimethylacetamide,1, 2-dichloroethane and N-methyl-2-pyrrolidinone. These polymers showed glass transition temperatures between 175°C and 229°C and decomposition temperatures at 5% weight loss ranging from 505 oC to 545 oC in nitrogen. These polymers with tensile strength of 48-75 MPa, elongation at break of 5.2-12.5 % and tensile modulus of 1.75-2.55 GPa.4. Several kinds of novel fluornted polyamides were synthesized from several diamino compounds with trifluoromethyl group and TCTPC by low temperature solution polycondensation under N2. The prepared fluorinated polyamides with inherent viscosities of 0.41-1.09 dL/g exhibit excellent heat-resistance. The Tgs of these polymers were ranged from 188 oC to 214 oC. These polymers with tensile strength of 71-121 MPa, elongation at break of 5.8-9.2 % and tensile modulus of 2.75-3.18 GPa were soluble in strongly polar organic aprotogenic solvents such as DMF,DMSO and NMP at room temperature.5. Aromatic polyesters containing trifluoromethylphenoxy pendant were synthesized by phase-transfer catalyzed interfacial polycondensation of 2-(4-trifluoromethylph- enoxy)terephthalyl chloride(TFPC) with 1, 1-bis(4-hydroxyphenyl)cyclohexane,1, 1-bis(4-hydroxyphenyl)-1-phenylethane,bis(4-hydroxyphenyl)diphenylmethane, 2, 2-bis(4-hydroxyphenyl)propane,9, 9-bis(4-hydroxyphenyl)xanthene and resorcinol, using toluene or dichloromethane as an organic solvent, sodium hydroxide as an acid acceptor, and benzyltriethylammonium chloride(BTEAC) as an emulsifier. The structure of these polyesters have been supported by infra-red and nuclear magnetic resonance spectral data. The inherent viscosities of polyesters were in the range 0.25–1.38 dL/g. All the polyesters were soluble in organic solvents such as dichloromethane,chloroform,tetrahydrofuran,pyridine,N, N-dimethylformamide,N, N-dimethylacetamide,1, 2-dichloroethane and N-methyl-2-pyrrolidinone. These polymers showed glass transition temperatures between 106°C and 210°C. The decomposition temperatures at 5% weight loss of these polymers in nitrogen were all over 450 oC. These polymers with tensile strength of 89-124 MPa, elongation at break of 6.7-11.7 % and tensile modulus of 1.98-3.65 GPa.6. A series of novel aromatic polyester-amides with trifluoromethylphenoxy unit were prepared from 2-(4-trifluoromethylphenoxy)-1, 4-bis(4-aminophenyl)phthalate and various aromatic diacid chlorides via the low-temperature solution polycondensation. The polymers with an inherent viscosity of 0.51–1.64 dL/g showed glass-transition temperatures between 166 oC and 256 oC and decomposition temperatures at 5% weight loss ranging from 376 oC to 384 oC in nitrogen. These polymers with tensile strength of 88-245 MPa , tensile modulus of 2.21-4.98 GPa and elongation at break of 5.8-39.2 %.