Solubility, Rheology, and Coagulation Kinetics of Poly-(O-Aminophenylene)Naphthoylenimide Solutions

The effect of temperature and storage time at a constant temperature on the stability of poly-(o-aminophenylene)naphthoylenimide solutions in N-methylpyrrolidone has been analyzed using rotational rheometry. A temperature–time window beyond which an irreversible change in the viscoelastic properties of solutions due to cumulative reactions of continuous polymerization and possible intramolecular cyclization has been detected. The influence of polymer concentration and its molecular weight on the rheological properties of solutions determining the choice of methods for their processing into fibers and films has been investigated. The effect of non-solvents (water and ethanol) additives on the rheological properties of solutions and the kinetics of their coagulation has been studied. Dosed addition of non-solvent into the solution promotes a significant increase in the viscoelasticity up to gelation and phase separation. Non-solvent presence in the polymer solutions reduces the activity of the solvent, accelerates the movement of the diffusion front at coagulation, and minimizes the number of macro defects. The combination of parameters under investigation renders it possible for the first time to develop new principles modifying dopes for wet spinning into aqueous or ethanol coagulation bath and finally to obtain a heat- and fire-resistant polynaphthoylenebenzimidazole fibers.

[1]  V. Kulichikhin,et al.  A Role of Coagulant in Structure Formation of Fibers and Films Spun from Cellulose Solutions , 2020, Materials.

[2]  V. Kulichikhin,et al.  The Effect of the Synthetic Procedure of Acrylonitrile–Acrylic Acid Copolymers on Rheological Properties of Solutions and Features of Fiber Spinning , 2020, Materials.

[3]  O. Serenko,et al.  New Approach to Preparation of Heat-Resistant “Lola-M” Fiber , 2019, Materials.

[4]  V. Kulichikhin,et al.  The Effect of Tetraethoxysilane on the Phase State, Rheological Properties, and Coagulation Features of Polyacrylonitrile Solutions , 2019, Colloid Journal.

[5]  A. Malkin,et al.  A Novel Technique for Fiber Formation: Mechanotropic Spinning—Principle and Realization , 2018, Polymers.

[6]  S. Ramakrishna,et al.  Recent advances in core/shell bicomponent fibers and nanofibers: A review , 2018 .

[7]  A. Malkin,et al.  From Polyacrylonitrile, its Solutions, and Filaments to Carbon Fibers II. Spinning PAN‐Precursors and their Thermal Treatment , 2018 .

[8]  N. Pan,et al.  Thermodynamic Study of a Water-Dimethylformamide- Polyacrylonitrile Ternary System , 2008 .

[9]  A. Shchetinin,et al.  Creation of High-Strength, Heat- and Fire-Resistant Synthetic Fibres , 2001 .

[10]  I. Tikhonov.  New organic materials with improved consumer properties and articles made from them , 1998 .

[11]  J. Masson.  Acrylic Fiber Technology and Applications , 1995 .

[12]  A. Rusanov,et al.  Flame‐resistant polynaphthoylenbenzimidazoles , 1993 .

[13]  D. R. Paul.  Diffusion during the coagulation step of wet-spinning , 1968 .

[14]  A. Rusanov,et al.  The effect of isomeric composition of the equilibrium rigidity of poly(naphthoylene benzimidazole) chains , 1992 .

[15]  A. Berlin,et al.  Synthesis of polynaphthoylene benzimidazoles based on dianhydrides of keto- and sulphone-bis-(4,5-dicarboxy-1-naphthyl) , 1981 .