Rigid‐Rod Polyamides from 3,3′‐bis­(trifluoromethyl)‐4,4′‐diamino‐1,1′‐biphenyl

Abstract

A diamine monomer with trifl uoromethyl groups, 3,3′-bis(trifl uoromethyl)-4,4′-diamino-1,1′-biphenyl, is synthesized from 5-bromo-2-nitrobenzotrifl uoride with two steps. The model reaction with monofunctional benzoyl chloride at room temperature gives the model compound with a quantitative yield. The results of the model reaction indicate that the amine groups have suffi cient reactivity in spite of the presence of electron-withdrawing and bulky trifl uoromethyl group at the ortho position. The monomer is polymerized with terephthaloyl chloride and isophthaloyl chloride in N,N -dimethylacetamide (DMAc) or DMAc containing LiCl using pyridine as an acid acceptor at room temperature. All synthesized polymers are somewhat crystalline and colorless. While the meta-linked polyamide ( PA2 ) shows excellent solubility in polar aprotic solvents, the para-linked one ( PA1 ) is dissolved in polar aprotic solvents containing LiCl and concentrated H 2 SO 4 . They show good thermal and thermooxidative stability as well as high melting temperatures.

New polyamides based on diacid with decanediamide and methylene groups and aromatic diamines

“…3 Hence worldwide research efforts are directed to improve the solubility and hence the processability of aromatic polyamides, without significantly lowering their other desired properties. [4][5][6][7][8] Copolyamides from 2, 6-naphthalene diacid with a mixture of two aromatic diamines containing ether linkage and meta-catenation moiety produced aramids which were soluble in solvents namely NMP and DMSO. Solubility of aromatic polyamides was enhanced by introducing cardo [9][10][11][12][13] and bulky pendant units [14][15][16][17][18][19] such as dibenzobarrelene/ crown ethers and acyclic ethylene oxide in the polyamide backbone.…”

“…However, high melting or glass transition temperature and poor solubility in common organic solvents restrict applications of these aromatic polyamides 3 . Hence worldwide research efforts are directed to improve the solubility and hence the processability of aromatic polyamides, without significantly lowering their other desired properties 4–8 . Copolyamides from 2, 6‐naphthalene diacid with a mixture of two aromatic diamines containing ether linkage and meta‐catenation moiety produced aramids which were soluble in solvents namely NMP and DMSO.…”

Synthesis and Properties of Fluorinated Polyimides from Rigid and Twisted Bis(Trifluoromethyl)Benzidine for Flexible Electronics

“…Among many approaches, the incorporation of trifluoromethyl (CF 3 ) groups onto polymer chains is considered as an effective means of realizing soluble and transparent PIs without deteriorating their excellent properties, not only because bulky CF 3 groups disturb the interactions and chain packing between the polymer chains, but also because the strength of the carbon-fluorine chemical bond is the one of the strongest single bonds [6,. It is also possible to give the corresponding PIs have many attractive features, such as a low refractive index as well as low optical loss, dielectric constant, surface energy, and moisture absorption characteristics, due to the high electronegativity and low electric polarity of fluorine atoms [31][32][33][34][35][36][37][38][39].…”

New soluble polyamides and polyimides containing polar functional groups: pendent pyrazole rings with amino and cyano groups

“…[3] Given these processing problems, a great deal of research on aromatic polyamides and polyimides has been conducted to increase their processability with minimal effects on the thermal stability and to improve their specific properties over the last few decades. [4][5][6][7][8] For example, polyamides and polyimides containing trifluoromethyl groups show a high modulus, a low thermal expansion coefficient as well as good solubility, [9][10][11][12][13][14][15][16][17][18][19][20][21] and the incorporation of heterocyclic units into polyimide chains increases the glass transition temperature and thermal stability. [22][23][24][25][26][27] Also, soluble polyamides and polyimides containing crosslinkable pendent groups represent useful methods in many applications.…”