Synthesis and Properties of Novel Poly(amide-imide)s Derived from 2,4-diaminotriphenylamine and Imide Ring-Preformed Dicarboxylic Acids

Optimization of Electrospun TORLON® 4000 Polyamide-Imide (PAI) Nanofibers: Bridging the Gap to Industrial-Scale Production

Polyamide-imide (PAI) is an exceptional polymer known for its outstanding mechanical, chemical, and thermal resistance. This makes it an ideal choice for applications that require excellent durability, such as those in the aerospace sector, bearings, gears, and the oil and gas industry. The current study explores the optimization of TORLON® 4000 T HV polyamide-imide nanofibers utilizing needleless electrospinning devices, ranging from laboratory-scale to industrial-scale production, for the first time. The PAI polymer has been dispersed in several solvent systems at varying concentrations. The diameter of the electrospun PAI nanofibers ranged from 65.8 nanometers to 1.52 μm. Their filtering efficiency was above 90% for particles with a size of 0.3 microns. The TGA results proved that PAI nanofibers have excellent resistance to high temperatures up to 450 °C. The PAI nanofibers are ideal for hot air intake filtration and fire-fighter personal protection equipment applications.

Microwave Encounters Ionic Liquid: Synergistic Mechanism, Synthesis and Emerging Applications

Progress in microwave (MW) energy application technology has stimulated remarkable advances in manufacturing and high-quality applications of ionic liquids (ILs) that are generally used as novel media in chemical engineering. This Review focuses on an emerging technology via the combination of MW energy and the usage of ILs, termed microwave-assisted ionic liquid (MAIL) technology. In comparison to conventional routes that rely on heat transfer through media, the contactless and unique MW heating exploits the electromagnetic wave-ions interactions to deliver energy to IL molecules, accelerating the process of material synthesis, catalytic reactions, and so on. In addition to the inherent advantages of ILs, including outstanding solubility, and well-tuned thermophysical properties, MAIL technology has exhibited great potential in process intensification to meet the requirement of efficient, economic chemical production. Here we start with an introduction to principles of MW heating, highlighting fundamental mechanisms of MW induced process intensification based on ILs. Next, the synergies of MW energy and ILs employed in materials synthesis, as well as their merits, are documented. The emerging applications of MAIL technologies are summarized in the next sections, involving tumor therapy, organic catalysis, separations, and bioconversions. Finally, the current challenges and future opportunities of this emerging technology are discussed.

Synthesis and Characterization of Novel Triphenylamine-Containing Electrochromic Polyimides with Benzimidazole Substituents

Two novel electrochromic aromatic polyimides (named as TPA-BIA-PI and TPA-BIB-PI, respectively) with pendent benzimidazole group were synthesized from 1,2-Diphenyl-N,N'-di-4-aminophenyl-5-amino-benzimidazole and 4-Amino-4'-aminophenyl-4″-1-phenyl-benzimidazolyl-phenyl-aniline with 4,4'-(hexafluoroisopropane) phthalic anhydride (6FDA) via two-step polymerization process, respectively. Then, polyimide films were prepared on ITO-conductive glass by electrostatic spraying, and their electrochromic properties were studied. The results showed that due to the π-π* transitions, the maximum UV-Vis absorption bands of TPA-BIA-PI and TPA-BIB-PI films were located at about 314 nm and 346 nm, respectively. A pair of reversible redox peaks of TPA-BIA-PI and TPA-BIB-PI films that were associated with noticeable color changed from original yellow to dark blue and green were observed in the cyclic voltammetry (CV) test. With increasing voltage, new absorption peaks of TPA-BIA-PI and TPA-BIB-PI films emerged at 755 nm and 762 nm, respectively. The switching/bleaching times of TPA-BIA-PI and TPA-BIB-PI films were 13 s/16 s and 13.9 s/9.5 s, respectively, showing that these polyimides can be used as novel electrochromic materials.

Synthesis and characterization of poly(amide-imide)s derived from a new ortho-functional unsymmetrical dicarboxylic acid

Herein, we report a new diacid monomer containing an imide ring and a methoxy pendant group, 3-trimellitimido-4-methoxybenzoic acid TMBA, for the preparation of poly(amide-imide)s.