Synthesis and characterization of highly soluble wholly aromatic polyamides containing both furanyl and phenyl units

Abstract

This paper presents the synthesis and characterization of two series of polymeric compounds comprising eight furan‐based polyamides prepared via melt polycondensation at low temperatures using various combinations of five aromatic raw materials. The chemical and physical structures and thermal stabilities of the obtained polyamides were investigated by various characterization methods. In addition, the polyamides were subjected to solubility testing in five common organic solvents. The results showed that the proposed furan‐based polyamides possessed thermal stabilities similar to those of conventional high‐performance aromatic polyamides, but with greatly improved solubility. Accordingly, the introduction of furan groups increased the solubility of the polyamides with respect to the solubility of their individual precursors, which is highly advantageous for subsequent polyamide processing and expanding their range of potential applications.

Preparation and properties of an aromatic polyamide fibre derived from a bio-based furan acid chloride

“…The inherent viscosity of the f-resin obtained was approximately 1.8 dL/g (number average molecular weight: 362,000; weight average molecular weight: 477,800; polydispersity index: 1.32), which meets the basic requirements for dry-jet wet spinning. The molecular weight and viscosity of the prepared f-resin are much higher than those reported previously for polyamides, 11,19,24 which exhibited inherent viscosities below 1 dL/g and number average weights below 100,000.…”

“…For the furan-containing samples, C-O stretching vibration peaks (1505 and 1487 cm �1 ), and C-C stretching vibration peaks (1015 and 972 cm �1 ) were also observed. With regard to the N-H stretching vibrations in the range of 3500-3200 cm �1 , Wilsens, 4 Yu, 19 and Abid 22 previously observed two peaks at 3278 and 3419 cm �1 , which were attributed to the stretching vibrations of the amide N-H bond in the hydrogen-bonded and non-hydrogen-bonded states, respectively. As shown in Figure 2, N-H stretching vibrations of hydrogen-bonded and non-hydrogen-bonded amides appeared at 3298 and 3411 cm �1 , respectively.…”

“…In the FTIR spectrum of f-resin, characteristic absorption peaks were assigned to the amide and benzene functional groups, as well as to the furan rings and diphenyl ether moieties. 3,4,15,[19][20][21][22] Peaks assigned to the N-H bond stretching vibration were located in the range 3298-3411 cm �1 , and at 1316 cm �1 . An amide I (C¼O stretching vibration) band and two amide II (N-H deformation vibration) bands were observed at 1655 cm �1 , and 1559 and 1535 cm �1 , respectively.…”

“…It is worth noting that the solubility of the f-resin is higher than that of the m-resin, as shown in Table 1, its observed solubilities in common polar solvents such as DMAC, NMP, and DMSO being consistent with the literature. 19,25,26 The cohesive energy density of the furan ring in the f-resin molecular chain is lower than that of a benzene-containing analogue. The polarity and flexibility of the polymer chain increased with the introduction of a furan ring and phenyl ether moieties, resulting in enhanced solubility.…”

“…8,9 Ongoing research on furan-ring-containing polyamides mainly focuses on two aspects. [8][9][10][11][12][13][14][15][16][17][18][19] One aspect is the solution or interfacial polycondensation of diamines and FDCA carried out at high temperatures, which is accompanied by FDCA decarboxylation. The polyamides obtained by this method often exhibit worse properties than comparable polyamides derived from petroleum.…”