Synthesis and Properties of Fluorinated Polyimides Based onFluorine-Containing Diamines Extended from 4,4'-Dihydroxybenzophenone and 3-Nitrophenol

• Main Authors: Su Yu-Yang, 蘇育央
• Other Authors: Yang Chin-Ping
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/70590783071177803303

碩士 === 大同大學 === 化學工程研究所 === 91 === Part I, A novel fluorinated diamime monomer with ether-ketone group, 4,4’-Bis(4-amino-2-trifluoromethyphenoxy)benzophenone (2) was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 4,4’-Dihydroxybenzophenone in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Polyimides 5a-f and copolyimides 5c/a-f were synthesized from 2 and various commercial aromatic dianhydrides ﹝PMDA, BTDA, BPDA, DSDA, ODPA and 6FDA (3a-f)﹞ via the thermal or chemical imidization. The 5 series had inherent viscosities ranging from 0.72 to 1.22 dL/g. Beside the chemical imidization of 5c(C), 5(C) series were soluble in amide-type solvents and even in less polar solvents, but 5a-f via thermal imidization showed insoluble. Polyimide films 5a-f show tensile strength ranging from 92 to 112 MPa, elongations to break from 8 to 15%, and initial moduli in 2.0-2.1 GPa. The glass transition temperature of 5 series were in the range of 232-278 ℃, and the 10% weight loss temperature were above 535 ℃, and they left more than a 50% char yield at 800 ℃ in nitrogen. Compared 5 series with analogous nonfluorinated polyimides 6 series based on 4,4’-Bis(4-aminophenoxy)benzophenone, 5 series revealed better solubility, lower color intensity, dielectric constant, and moisture absorption. Their films had cutoff wavelengths between 370-410 nm, b* values ranging from 9.6 to 58.3, dielectric constants of 3.05-3.64 (1 MHz), and moisture absorption in the range of 0.08-0.38 wt%. Part II, A colorless fluorinated diamine, 3’-trifluoromethy-3,4’-oxydianiline (3’-CF3-3,4’-ODA) (2’) was prepared through the nucleophilic substitution reaction of 3-nitrophenol and 2-chloro-5-nitrobenzotrifluoride, followed by catalytic reduction with hydrazine and Pd/C. A series of Polyimides 5’ were synthesized from the diamine 2’ with various aromatic dianhydrides 3’a-f via the thermal and chemical imidization. These polyimides had inherent viscosities ranging from 0.88 to 1.12 dL/g. A comparison of 5’, 6’ to analogous polyimides 7’, 8’, which 6’, 7’ and 8’ were based on 3’4-ODA, 3-CF3-4,4’-ODA, 4,4’-ODA, respectively. In terms of the colorness of PI revealed that the color intensity of phenoxy-containing amine of the meta-structure and the para-structure with the CF3 group would fell off color intensity. The color intensity of the four polyimide series was lessened in the following order: 5’ > 7’ > 6’ > 8’. The solubility of 5’ is better than 6’, 7’ and 8’. The polyimide 5’ films had a tensile strength ranging from 124 to 147 MPa, elongation at break from 9 to 65%, and initial modulus from 2.3 to 2.8 GPa. The glass transition temperature of polymers was recorded at 234—313 ℃. They had 10% weight loss at a temperature above 515 ℃ and left more than 50% residue even at 800 ℃ in nitrogen. Compared with polyimides 6’, 5’ showed the lower dielectric constants of 2.80—3.50 (40 MHz), and moisture absorptions in the range of 0.44—1.02 wt%.