We describe herein the state of the art following the last 8 years of research into aromatic polyamides, wholly aromatic polyamides or aramids. These polymers belong to the family of high performance materials because of their exceptional thermal and mechanical behavior. Commercially, they have been transformed into fibers mainly for production of advanced composites, paper, and cut and fire protective garments. Huge research efforts have been carried out to take advantage of the mentioned characteristics in advanced fields related to transport applications, optically active materials, electroactive materials, smart materials, or materials with even better mechanical and thermal behavior.

Functional Aromatic Polyamides

Sulfonated aromatic polyamide as water-soluble polymeric corrosion inhibitor of copper in HCl

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pol.20210001

Recent development of polyimides: Synthesis, processing, and application in gas separation

https://pubs.rsc.org/en/content/articlepdf/2021/CC/D1CC05157A

Metal-organic frameworks (MOFs) as host materials for the enhanced delivery of biomacromolecular therapeutics.

This study includes the fabrication of highly sulfonated polyethersulfone (SPES)/polyethersulfone (PES) blended membranes with superior properties for effective oil/water separation. In this regard membranes with different content of SPES and degree of sulfonation (DS) were fabricated. Highly sulfonated PES was synthesized by chlorosulfonic acid and concentrated sulfuric acid at low temperature. FTIR and DS analysis confirmed the presence of sulfonic acid groups on the PES backbone. The phase inversion process of membrane fabrication was studied by ternary phase diagram construction and dope solutions viscosity measurement. Fabricated membranes were characterized by SEM, water contact angle, porosity, pure water flux, and mechanical strength. The SEM images demonstrated that blended membranes have wider finger-like pores in their structure compared to bare PES membrane. Results indicated that by increasing SPES content and DS, permeability increased but mechanical strength decreased. The membranes fabricated by 50% SPES with 37% DS and 50% PES has the highest permeability (59.89 l/m2.h) with 93.3% oil rejection. Also antifouling properties of blended membranes improved remarkably compared to PES membrane.

Morphological and performance evaluation of highly sulfonated polyethersulfone/polyethersulfone membrane for oil/water separation

Conjugated polymers are usually synthesized by homogeneous palladium complexes-catalyzed Heck, Suzuki, and Stille coupling reactions, which suffer from the non- recyclability of expensive palladium catalysts and palladium contamination of the desired polymer due to palladium leaching. In order to overcome these drawbacks, a bidentate phosphino-modified magnetic nanoparticles-anchored palladium complex (PdCl2-Fe3O4@SiO2-2P) as a clean and efficient heterogeneous catalyst for the carbon–carbon coupling polycondensations was developed in present work. The PdCl2-Fe3O4@SiO2-2P catalyst exhibited an enhanced catalytic activity for Heck, Suzuki, and Stille coupling polymerizations, as compared with the most commonly used homogeneous Pd(PPh3)4. Moreover, this heterogeneous palladium catalyst showed advantage of much less palladium impurity (below 13 ppm) in the isolated polymers. Importantly, PdCl2-Fe3O4@SiO2-2P can facilely be separated from the reaction products and recovered by using an external magnetic field, and recycled at least eight times with almost consistent catalytic activity.

Recyclable heterogeneous palladium-catalyzed carbon–carbon coupling polycondensations toward highly purified conjugated polymers

Three diamine monomers containing pyridine groups were prepared via the modified Chichibabin reaction of aromatic aldehydes with 4′-nitroacetophenone, followed by reduction with hydrazine hydrate in the presence of Pd/C. Novel aromatic polyamides containing 4-aryl-2,6-diphenylpyridine moieties and pendant fluorinated phenoxy groups were synthesized from these diamines and two fluorinated isophthaloyl dichlorides by the low temperature solution polycondensation in N,N-dimethylacetamide (DMAc). All the polymers are amorphous and readily soluble in strong polar organic solvents such as DMAc, N-methyl-2-pyrrolidinone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) at room temperature. The resulting polymers showed glass transition temperatures between 270 and 314 °C and 5 % weight loss temperatures ranging from 442 °C to 475 °C, and char yields at 800 °C higher than 53 % in nitrogen. These polyamides could be cast into transparent, flexible and strong films from DMAc solution with tensile strengths of 72.5–87.3 MPa, tensile moduli of 2.35–2.87 GPa, and elongations at break of 5.3–9.5 %. The polyamide films exhibited low dielectric constants of 3.21–3.54 (1 MHz), low water uptakes in the range of 1.17–1.38 %, and high transparency with an ultraviolet-visible absorption cut-off wavelength in the 380–391 nm range.

Synthesis and properties of novel soluble aromatic polyamides containing 4-aryl-2,6-diphenylpyridine moieties and pendant fluorinated phenoxy groups

New cardo poly(arylene ether ketone amide)s were synthesized by heterogeneous palladium-catalyzed carbonylative polycondensation of aromatic diiodides with ether–ketone linkages, aromatic diamines bearing cardo groups, and carbon monoxide. Polymerizations were conducted in N,N-dimethylacetamide (DMAc) at 120 °C in the presence of a bidentate phosphino-functionalized magnetic nanoparticles-immobilized palladium complex [Fe3O4@SiO2-2P-PdCl2] and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU), yielding a series of cardo poly(arylene ether ketone amide)s with inherent viscosities up to 0.77 dL/g. All the polymers were readily soluble in various dipolar aprotic solvents at room temperature. These polymers showed good thermal stability with the glass transition temperature of 223–289 °C, the temperature at 5% weight loss of 441–464 °C in nitrogen. These cardo poly(arylene ether ketone amide)s could afford transparent, flexible, and strong films by solution-casting with good tensile properties. These polymer films exhibited lower dielectric constants, lower water uptakes, and higher optical transparency. Furthermore, this heterogeneous palladium catalyst can facilely be separated from the reaction mixture by simply applying an external magnet and recycled at least eight times with almost consistent activity.

Synthesis of cardo poly(arylene ether ketone amide)s by heterogeneous palladium-catalyzed polycondensation of aromatic diiodides, aromatic diamines containing cardo groups and CO

New aromatic polyamides containing cardo groups and triphenylphosphine oxide structures were synthesized by a heterogeneous palladium-catalyzed carbonylation and condensation of bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), aromatic diamines bearing cardo groups, and carbon monoxide. Polycondensations were carried out in N,N-dimethylacetamide under 1 atm of CO at 120 °C in the presence of a magnetically recyclable heterogeneous palladium catalyst and 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU) and afforded novel aromatic polyamides with inherent viscosities between 0.72 and 0.76 dL/g. All the polyamides were quite soluble in dipolar aprotic solvents and pyridine and could be converted into transparent, flexible, and tough polyamide films by casting from DMAc solutions. These polymers exhibited high thermal and thermooxidative stability with the glass transition temperatures of 237 °C–256 °C, the temperatures at 5% weight loss of 448 °C–465 °C in air. All the phosphorus-containing polyamides self-extinguished as soon as the flame was removed, and the limited oxygen indices (LOIs) of these polymers were in the range of 39%–44%. The polymer films also showed good mechanical properties and high optical transparency.

Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium-catalyzed carbonylation and condensation reaction

Feihua Zou

Papers

Recyclable heterogeneous palladium-catalyzed carbon–carbon coupling polycondensations toward highly purified conjugated polymers

Synthesis and properties of novel soluble aromatic polyamides containing 4-aryl-2,6-diphenylpyridine moieties and pendant fluorinated phenoxy groups

Synthesis of cardo poly(arylene ether ketone amide)s by heterogeneous palladium-catalyzed polycondensation of aromatic diiodides, aromatic diamines containing cardo groups and CO

Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium-catalyzed carbonylation and condensation reaction