Viscoelastic properties and structure of poly(acrylonitrile‐co‐methacrylic acid) polymer solutions for gel spinning at long aging times

Abstract

The objective of the research is to obtain a more complete understanding of how aging affects the viscoelastic properties of polymer solutions to be used as starting materials for gel spinning of polymer fibers. Specifically, poly(acrylonitrile‐co‐methacrylic acid) solutions were prepared and characterized using rheological measurements and nuclear magnetic resonance spectroscopy. The results indicate that elastic character increased with increasing polymer concentration and that gelation of these solutions continued up to aging times of several weeks. Additionally, comparing the results from the two characterization methods show that while gelation continues to occur, the viscoelastic properties decrease after a critical time point suggesting that a chemical change occurs in the solutions at long times. However, these changes impact the solution dynamics minimally as the effective network properties were similar at the aging times studied here, but considerations for long‐term storage of polymer solutions for gel spinning are warranted. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39821.

Prominent processing techniques to manipulate semiconducting polymer microstructures

“…Aging polymer solutions is a well-known procedure to induce aggregation/cluster/ordered structure formation [439][440][441] Fig. 11 and thus to eventually change the viscosity of solutions.…”

“…Aging polymer solutions is a well-known procedure to induce aggregation/cluster/ordered structure formation 439–441 and thus to eventually change the viscosity of solutions. 439,440,442,443 For example, it was shown that the viscoelastic properties of amphiphilic polymer-polyacid supramolecular solutions increased significantly with aging over a period of 30 days until a strong gel was formed, demonstrating the aging time is an important parameter that has to be considered when developing supramolecular systems via the electrostatic interaction between the amphiphilic polycations and polyacid.…”

“…Aging polymer solutions is a well-known procedure to induce aggregation/cluster/ordered structure formation 439–441 and thus to eventually change the viscosity of solutions. 439,440,442,443 For example, it was shown that the viscoelastic properties of amphiphilic polymer-polyacid supramolecular solutions increased significantly with aging over a period of 30 days until a strong gel was formed, demonstrating the aging time is an important parameter that has to be considered when developing supramolecular systems via the electrostatic interaction between the amphiphilic polycations and polyacid. 443 Moreover, spin casting aged solutions on solid substrates led to modifications in the film thickness and surface microstructure.…”

Supramolecular Structure and Mechanical Properties of Wet-Spun Polyacrylonitrile/Carbon Nanotube Composite Fibers Influenced by Stretching Forces

“…Incorporation of CNTs in PAN microfibers has the potential to improve the physical, mechanical, electrical, and thermal properties of PAN fibers. This can be achieved without any significant weight change and or need to use different production equipment (Brown et al, 2014;Sahin et al, 2014;Li et al, 2018;Mirbaha et al, 2019). These fibers have the potential to be used as a carbon fiber precursor (Mikolajczyk et al, 2010;Sahin et al, 2014).…”