Synthesis and properties of polyimides from 1,4-bis(4-amino-2-phenylphenoxy) benzene and 4,4′-bis(4-amino-2-phenylphenoxy) biphenyl

Abstract

Diamines, namely, 1,4-bis(4-amino-2-phenylphenoxy) benzene (1) and 4,4 0 -bis(4-amino-2-phenylphenoxy) biphenyl (2), were synthesized from 4-fluoro-3-phenyl nitrobenzene. Two series of polyimides were synthesized from these diamines with nine types of dianhydrides by a conventional two-step procedure that included ring-opening polymerization in N-methyl-2-pyrrolidone and subsequent thermal cyclic dehydration. The polyimides were characterized by x-ray diffraction, differential scanning calorimetry, thermogravimetry and dynamic mechanical analysis. The polyimides from 1 and 2 had a glass transition temperature in the range of 221-254 C and 222-271 C, respectively, and all the polymers were amorphous. The structure-property relationships of these polyimides were examined and compared with those of the previously prepared analogous polyimides from the bis(4-amino-2-biphenyl)ether (3). Water absorption and dielectric constants (e) of the polyimides were compared and discussed on the basis of imide content per repeating unit.

Influences of liquid electrolyte and polyimide identity on the structure and conductivity of polyimide–poly(ethylene glycol) materials

“…The only detectable structural difference between these two polyimides is the presence of P aOF in only the ODPA material. This trend is expected based on the lack of structural features seen in previously studied fluorinated polyimides and possible aromatic interaction and order generally seen in nonfluorinated polyimides . Both systems show shoulders that are essentially identical in size and are similar in size to PEG domains found in previously studied PEG–imide systems .…”

“…The more bulky fluorinated dianhydride is expected to have more free volume and more mobility than the ether‐containing dianhydride based on previous work studying polyimides . The additional free volume and mobility could lead to a higher possible ionic liquid uptake.…”

Synthesis and Characterization of Polyimide from 4,4’-Diamino diphenyl ether having Substituents at 2,2’-position

“…The order of increasing water absorption was PI2x, PI1x ＜ PI3x. Water absorption decreased with the increasing number of phenylene units in the case of polyimides prepared from dianhydrides b, c, d, e and f as previously reported [13], and decreased with decreasing imide content per the repeating unit. The values of water absorption were plotted as a function of the imide group content for all the polyimides, PI3x, PI1x and PI2x, defined as the formula weight (O=C-N-C=O) per that of the repeating unit (Figure 1-b).…”

“…The values of PI3x with the highest imide group contents were the highest, those of PI2x having low-polar trifluoromethyl groups were lowest, and the order of ε cal was PI2x ＜ PI1x ＜ PI3x. A positive correlation was observed betweenε cal and the imide group content as in the case of previously reported polyimides (Figure 3-b) [13,16,17], and the change rate of the values to the imide group contents for PI2x was the lowest. …”

“…The values of water absorption were plotted as a function of the imide group content for all the polyimides, PI3x, PI1x and PI2x, defined as the formula weight (O=C-N-C=O) per that of the repeating unit (Figure 1-b). A positive correlation was observed as previously reported [13,14]. The refractive indices (n) of polyimides PI3x were measured, and dielectric constants ( ε cal ) were estimated using the empirical relationship; ε cal = 1.1 n 2 [14,15] derive from the relationship among velocity of light (C), dielectric constant (ε) and magnetic permeability (μ), C = , and compared with those of PI1x and PI2x (Figure 3-a).…”