Synthesis of organosoluble copolyimide and preparation of fibers by dry-spinning process on a large scale

Abstract

An organosoluble copolyimide (co-PI) was synthesized from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 1,4-bis-(4-aimino-2-triflupromethyl-phenoxy)-benzene ( p-6FAPB), and 2-(4-aminophenyl)-5-aminobenzimidazole (BIA) via the one-step polymerization using N-methyl-2-pyrrolidone (NMP) as the solvent, and high-performance co-PI fibers were directly prepared by the dry-spinning process on a large scale. Scanning electron microscopic images show that all formulations of as-spun fibers exhibit elliptical cross sections as well as dense morphologies. The structural evolution of the co-PI fiber induced by the high rolling speed and post-heat-drawing treatment was studied by means of thermogravimetric analysis, dynamic thermomechanical analysis, and two-dimensional wide-angle X-ray diffraction (2D WAXD). With increasing rolling speeds, glass transition temperatures ( Tgs) and thermal stabilities of as-spun fibers slightly decrease, which may be resulted from the disentanglement of entangled molecular chains under the large deformation and high-temperature heating atmosphere in the spinning column. 2D WAXD data indicate that both increasing rolling speeds and post-heat-drawing treatment are beneficial for getting a highly ordered structure along the meridian direction of the fibers. The fibers treated at 430°C exhibit outstanding mechanical properties, and the tensile strength and modulus reach 1.44 GPa and 48.69 GPa, respectively, at a drawing ratio of 2.8.

Functionalized polyimide based on mercaptoacetic acid locking imine reaction: Synthesis and coating application

“…Furthermore, to ensure that the film forming processability is improved with maintained excellent comprehensive properties. So far, the main method to address this problem is cross‐linking 16,17 . However, cross‐linking requires special reaction condition, such as high temperature, 18 humidity, 19 or catalyzer, 20 and brings by‐products that may cause degradation in PI performances.…”

Structural evolution from poly(amic acid) to polyimide fibers during thermal imidization process

“…6 Among them, the PI fiber is now attracting researchers' interests as a new typical high-performance polymer fiber, which exhibits great potential applications in the special protective clothing, advanced wave-transparent composites, hightemperature filter bags, and so on. 7 Over the past several decades, preparation of highperformance PI fibers has made a significant progress. PI fibers are generally prepared by two main methods: dry-spinning process and wet-spinning process.…”

“…6 Among them, the PI fiber is now attracting researchers’ interests as a new typical high-performance polymer fiber, which exhibits great potential applications in the special protective clothing, advanced wave-transparent composites, high-temperature filter bags, and so on. 7…”

“…For instance, in our recent work, a novel PI fiber has been successfully fabricated via the dry-spinning process based on 3,3′,4,4′-benzophenonetetracarboxylic-dianhydride, 1,4-bis-(4-aimino-2-trifluoromethyl-phemoxy)-benzene ( p -6FAPB) and 2-(4-aminophenyl)-5-aminobenzimidazole (BIA) containing ether units, and the obtained fiber exhibited dense and homogenous microstructure and excellent mechanical properties. 7 Alternatively, the wet-spinning method has also been widely utilized in the preparation of PI fibers and is promising for realizing an industrial-level production of PI fibers. Relatively, the requirements for the poly(amic acid) (PAA) or the PI in the wet-spinning method is not as harsh as that of the dry spinning, which is more suitable to prepare PI fibers with a rigid-rod chemical structure.…”

High-performance polyimide nanofiber membranes prepared by electrospinning

“…[16][17][18] Among them, the synthesis of PI with excellent solubility in environmentally friendly solvents has been regarded as one of the most effective approaches. Until just recently, several new PIs [19][20][21] possessing good dissolvability in low-toxic solvents such as NMP, DMAc, or DMF have been synthesized, which provides a brand-new prerequisite to prepare PI fibers based on the one-step method.…”