Soluble para-linked aromatic polyamides with pendent groups

Functional Aromatic Polyamides

“…As it was pointed out previously, Lee et al [ 93 ] obtained a series of para -linked aromatic polyamides with trifluoromethyl or cyano groups in the main chain. They were soluble in polar aprotic solvents while the aramids without these groups needed the addition of salts to be solved in aprotic solvents, even though they had flexible ether linkages, which are solubility promoters ( Scheme 24 , P46-1 to P46-3).…”

“…Lee et al [ 93 ] studied a series of para -linked aromatic polyamides having η inh of 0.51 to 0.91 dL/g, that were prepared from 2-trifluoromethyl-4,4′-diaminodiphenyl ether, 2-cyano-4,4′-diaminodiphenyl ether, 2-trifluoromethyl-4,4′-diaminodiphenyl sulfide, and 2,2′-bis(trifluoromethyl)-4,4′-diaminodiphenyl sulfide. All of the synthesized polyamides presented low refractive indices ( n ) in the range of 1.616 to 1.661 and low birefringence (Δ) in the range of 0.010 to 0.031 with slightly higher n xy than n z , indicating that the polyamides films were slightly anisotropic.…”

“…Cast films out of these polyamides were clear and flexible with tensile strengths and elasticity modulus up to 88 MPa and 1.81 GPa, respectively. Para -linked aromatic polyamides with CF 3 pendant groups ( Scheme 39 , P65–P66) were synthetized by Lee et al [ 93 ] and compared with the same polyamides without the CF 3 groups. The polyamides without pendant groups showed poor solubility and required LiCl to dissolve in polar aprotic solvents, while the synthesized polyamides with CF 3 ( Scheme 39 , P65-1, P66-1, P66-2) groups showed enhanced solubility as well as good thermal stability.…”

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.…”