New aromatic polyamides with 2,6-biphenylpyridyl moieties and 4-trifluoromethylphenyl pendent groups

Abstract

A new diamine, 4-(4-trifluoromethylphenyl)-2,6-bis(4-aminophenyl)pyridine, was synthesized and used in the preparation of the fluorinated polyamides with inherent viscosities of 0.67–0.96 dL g−1 by direct polycondensation with aromatic dicarboxylic acids. The obtained polyamides have good solubility in many organic solvents such as N-methyl-2-pyrrolidinone, dimethylacetamide (DMAc), and tetrahydrofuran and exhibited glass transition temperatures between 275°C and 301°C, 10% weight loss temperatures ( Td10s) ranging from 502°C to 516°C, and char yields of 51–61% at 800°C under nitrogen atmosphere. Flexible and strong polymer films cast from DMAc solutions showed tensile strengths of 77.4–93.2 MPa, elongations at break of 9.2–14.3%, and initial moduli of 2.06–2.82 GPa. The polymer films also had good dielectric properties with dielectric constants of 3.22–3.50 (1 M Hz) and dissipation factors of 3.20–3.96 × 10−3, and acceptable electrical insulating properties, as well as low water uptake between 1.26% and 1.78%, and high transparency with an ultraviolet–visible absorption cutoff wavelength in the range of 330–371 nm. The remarkable combined features ensure these polymers to be ideal candidate materials for advanced microelectronic industry and other related applications.

Solution‐processable and electroactive aromatic polyamides with 3,5‐bis(trifluoromethyl)triphenylamine moiety

“…One of the common approaches for increasing solubility and processability of aramids without much sacrificing their high thermal stability is the introduction of bulky, packing‐disruptive groups into the polymer backbone . Introduction of trifluoromethyl (CF 3 ) groups into aramids has been one of the most widely used strategies for structural modification leading to substantial solubility enhancement . It has also been demonstrated that aramids containing three‐dimensional, propeller‐shaped triphenylamine (TPA) unit are amorphous, have good solubility in organic solvents and good film‐forming capability, and exhibit high thermal stability .…”

High optical transparency, low dielectric constant, and light color of organosoluble polyamides based on 10,10-bis[4-(4- amino-3-trifluoromethylphenoxy)phenyl]- 9(10H)-anthrone

“…Obviously, for obtaining PA films, it is essential to restrain the crystallization and orientation of the molecular chains of the polymers. Thus, a variety of structural modifications, such as insertion of flexible linkages, 4,5 bulky units, 6,7 and pendent groups 8 –10 into the polymer backbone, as well as utilization of noncoplanar or asymmetric monomer, 11,12 have been used to modify the polymer properties, either by lowering the interchain interaction or by reducing the stiffness of the polymer chain. Among them, it was found that incorporation of the fluorine groups like trifluoromethyl (CF 3 ) groups into PA backbones resulted in great benefits for improving the polymers, some properties such as solubility and optical transparency, as well as reducing the moisture absorption, crystallinity, dielectric constant, and color.…”

Ultrahigh strength and modulus copolyamide films with uniaxially cold-drawing induced molecular orientation

“…[1][2][3][4] The best known commercial aramids are poly(p-phenylene terephthalamide) (PPTA). These polymers are mainly used as flame-resistant and high tensile strength fibers.…”