Synthesis and properties of novel polyamides containing sulfone‐ether linkages and xanthene cardo groups

Abstract

In order to obtain polyamides with enhanced solubility and processability, as well as good mechanical and thermal properties, several novel polyamides containing sulfone‐ether linkages and xanthene cardo groups based on a new diamine monomer, 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX), were investigated. The BAPX monomer was synthesized via a two‐step process consisting of an aromatic nucleophilic substitution reaction of readily available 4‐chloronitrobenzene with 9,9‐bis(4‐hydroxyphenyl)xanthene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. Four novel aromatic polyamides containing sulfone‐ether linkages and xanthene cardo groups with inherent viscosities between 0.98 and 1.22 dL g−1 were prepared by low‐temperature polycondensation of BAPX with 4,4′‐sulfonyldibenzoyl chloride, 4,4′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride, 3,3′‐[sulfonyl‐bis(4‐phenyleneoxy)]dibenzoyl chloride and 4,4′‐[sulfonyl‐bis(2,6‐dimethyl‐1,4‐phenyleneoxy)]dibenzoyl chloride in N,N‐dimethylacetamide (DMAc) solution containing pyridine. All these new polyamides were amorphous and readily soluble in various polar solvents such as DMAc and N‐methylpyrrolidone. These polymers showed relatively high glass transition temperatures in the range 238–298 °C, almost no weight loss up to 450 °C in air or nitrogen atmosphere, decomposition temperatures at 10% weight loss ranging from 472 to 523 °C and 465 to 512 °C in nitrogen and air, respectively, and char yields at 800 °C in nitrogen higher than 50 wt%. Transparent, flexible and tough films of these polymers cast from DMAc solution exhibited tensile strengths ranging from 78 to 87 MPa, elongations at break from 9 to 13% and initial moduli from 1.7 to 2.2 GPa. Primary characterization of these novel polyamides shows that they might serve as new candidates for processable high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry

Organosoluble, low‐dielectric‐constant fluorinated polyimides based on 9,9‐bis[4‐(4‐amino‐2‐trifluoromethyl‐ phenoxy)phenyl]xanthene

“…In the present study, the trifluoromethyl‐substituted aromatic diamine BATFPX is less reactive to dianhydrides than conventional aromatic diamines because of the electron‐withdrawing trifluoromethyl groups. However, the new polyimides resulting from BATFPX would be soluble in common organic solvents on the basis of our previous investigation on cardo polyamides with bulky xanthene structure 38. Therefore, the one‐step polymerization procedure was chosen here for the synthesis of polyimides 5a – 5e on the basis of the two reasons, as shown in Scheme .…”

“…We previously successfully synthesized soluble high‐temperature aromatic xanthene‐containing cardo poly(arylene ether ketone)s37 and polyamides38 with enhanced solubility and excellent mechanical properties as well as good thermal and thermo‐oxidative stability. In the work reported here, as part of an ongoing project dealing with the development of processable high‐performance polymeric materials, a novel aromatic diamine, 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene, with trifluoromethyl substituent, bulky cardo xanthene group and flexible ether linkage, was synthesized and then polymerized with five commercial dianhydrides to produce a series of fluorinated polyimides.…”

Synthesis and properties of novel soluble polyamides containing both fluorene or xanthene cardo moieties and fluorinated phenoxy pendant groups

“…As outlined in Scheme , 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]xanthene (BAFPX) was synthesized in two steps according to a similar procedure for the synthesis of BAPX . The dinitro compound (BNFPX) was obtained by the aromatic nucleophilic substitution reaction of BHPX with 2‐chloro‐5‐nitrobenzotrifluoride in the presence of K 2 CO 3 in DMF.…”

“…5‐(4‐Trifluoromethylphenoxy)isophthaloyl chloride (3F‐IPC) and 5‐(3,5‐bis(trifluoromethyl)phenoxy)isophthaloyl chloride (6F‐IPC) were prepared according to the literature procedure . Three aromatic diamines containing cardo groups—9,9‐bis[4‐(4‐aminophenoxy)phenyl]fluorene (BAPF) , 9,9‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]fluorene (BAFPF) , and 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX) —were synthesized according to the reported methods.…”

“…To overcome these limitations, many efforts have been made to improve their solubility and dielectric properties without thermal stability and mechanical properties being sacrificed. The introductions of flexible segments—such as ether or sulfone linkages , bulky pendant or cardo groups , unsymmetrical , and noncoplanar structures —into polymer backbone have been employed as successful approaches to modify aramid properties.…”