Synthesis and properties of novel aromatic polyamides with xanthene cardo groups

Abstract

Two novel monomers, 9,9-bis[4-(4-carboxyphenoxy)phenyl]xanthene (BCAPX) and 9,9-bis[4-(4-aminophenoxy)phenyl]xanthene (BAPX) were prepared in two main steps starting from nucleophilic substitution of 9,9-bis(4-hydroxyphenyl)xanthene (BHPX) with p-fluorobenzonitrile and p-chloronitrobenzene, respectively. Using triphenyl phosphite and pyridine as condensing agents, two series of polyamides containing xanthene cardo groups with the inherent viscosities (0.82-1.32 dL/g) were prepared by polycondensation from BCAPX with various aromatic diamines or from BAPX with various aromatic dicarboxylic acids in an N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride, respectively. All new polyamides were amorphous and readily soluble in various polar solvents such as N,N-dimethylformamide (DMF), NMP, N,N-dimethylacetamide (DMAc) and pyridine. These polymers showed relatively high glass transition temperatures between 264 and 308 C, decomposition temperatures at 10% weight loss ranging from 502 to 540 C and 488 to 515 C in nitrogen and air, respectively, and char yields at 800 C in nitrogen higher than 56%. Transparent, flexible, and tough films of these polymers cast from DMAc solutions exhibited tensile strengths ranging from 86 to 109 MPa, elongations at break from 13 to 22%, and initial moduli from 2.15 to 2.63 GPa.

New soluble, transparent and heat-resistant poly(ether amide)s based on 10,10-bis[4-(4-aminophenoxy)-3-methylphenyl]-9(10H)-anthrone

“…First of all, 10,10-bis(4-hydroxy-3-methylphenyl)-9(10 H )-anthrone ( 1 ) was prepared in good yield via one-pot, two-step synthetic procedure by reaction of 9(10 H )-anthrone with thionyl chloride, affording 10,10-dichloro-9(10 H )-anthrone, followed by treatment with o -cresol in the refluxing xylene using a similar method. 16 But it should be noted that the expected product, 9,9-bis(4-hydroxy-3-methylphenyl)-9,10-dihydroanthracene ( 1′ ), was not obtained under the same conditions. Secondly, reaction of bisphenol intermediate ( 1 ) with 4-chloronitrobenzene in the presence of potassium carbonate afforded the dinitro compound, 10,10-bis[4-(4-nitrophenoxy)-3-methylphenyl]-9(10 H )-anthrone ( 2 ).…”

“…There is no doubt that ideal structure modification of polymer is expected to provide balanced properties of high thermal stability and good processability. It has been demonstrated that PAs bearing bulky cyclic side groups (usually named as cardo groups) such as fluorene, 11 –13 phthalide, 14 tert -butylcyclohexylidene, 15 xanthene, 16,17 or cyclopentylidene 18 can exhibit a significant increase in both glass transition temperature ( T g ) and thermooxidative stability while providing good solubility. The 9(10 H )-anthrone structure as a bulky pendent group was previously incorporated into the polymer backbones of the PAs and polyimides to improve their processability based on 10,10-bis(4-aminophenyl)-9(10 H )-anthrone monomer.…”

Functional Aromatic Polyamides

“…Jian et al [48] and Sheng et al [59] described the synthesis of aromatic polyamides containing ether and bulky xanthene groups from a diacyl chloride monomer, 9,9-bis[4-(chloroformylphenoxy)phenyl]xanthene, or a diamine monomer, 9,9-bis[4-(4-aminophenoxy) phenyl]xanthene (Scheme 29, P52-P53). The polyamides were amorphous and soluble in polar Palí et al [139] reported on the study of the influence of controlled structural modifications on physical and conformational properties of isomeric aromatic polyamides with different bulky pendant lateral groups (Scheme 28, P51).…”

“…The polymers, with ether and bulky xanthenes groups (η inh from 0.72 to 0.98 dL/g), showed good mechanical properties (tensile strengths ranging from 82 to 106 MPa, elongations at break from 10 to 25%, and initial moduli from 2.0 to 2.8 GPa). Sheng et al [ 59 ] also described the preparation of aramids with xanthene moietis, starting from 9,9-bis[4-(4-carboxyphenoxy) phenyl]xanthene and 9,9-bis[4-(4-aminophenoxy) phenyl]xanthene. The polymers had η inh from 0.82 to 1.32 dL/g and gave flexible and transparent films by casting (moduli from 2.15 to 2.63 GPa, tensile strengths ranging from 86 to 109 MPa and elongations at break from 13 to 22%).…”

“…Jian et al [ 48 ] and Sheng et al [ 59 ] described the synthesis of aromatic polyamides containing ether and bulky xanthene groups from a diacyl chloride monomer, 9,9-bis[4-(chloroformylphenoxy)phenyl]xanthene, or a diamine monomer, 9,9-bis[4-(4-aminophenoxy) phenyl]xanthene ( Scheme 29 , P52–P53). The polyamides were amorphous and soluble in polar solvents such as DMA, DMF, NMP and pyridine, showed relative high T g s (236–308 °C), decomposition temperatures at 10% mass loss from 490 to 540 °C in air, and char yields higher than 50% in nitrogen.…”