Vol 49, No 3 (2017)

The problems associated with theoretical concepts of electrospinning and determination of the influence of macromolecular factor (precisely molecular mass), molecular mass distribution, chain flexibility, and solution quality on electrospinning are studied. This concept is pitted against the previously known theory supporting decisive influence of electrophysical properties of solutions without regard for the nature of the dissolved substances, including polymers. The domestic and foreign works confirming the chosen concept are reviewed. Various empirical models that allow prediction of transition of electrospraying process to process of electrospinning of defect-free fibres are proposed.

The influence of the molecular mass of poly-N-vinylpyrrolidone on the rheological, visco-elastic, relaxation properties of solutions and on their structure and stability of the process of obtaining fibers by electrospinning is considered. The critical values of the concentration and molecular mass of the polymer for carrying out stable electrospinning of the fiber are established, and the relationship between the molecular mass and the concentration, viscosity of the solutions, and technological parameters of the spinning process is determined.

Various fine fiber materials with improved properties, promising for use in the filtration of gases and liquids, in medicine, electronics and other industries, were produced by the method of electrospinning from polymer melts, first introduced 35 years ago. The article gives an overview of the literature data on the problem of obtaining nonwoven materials by electrospinning from polymer melts, including methods for regulating the diameter of the fibers formed, obtaining mixed and hybrid materials, and also the hardware design for these processes.

Nanocrystalline chitin and cellulose were obtained by acid hydrolysis. Their morphology and size distribution were investigated by atomic-force microscopy, dynamic laser light scattering, and UV spectrophotometry. The effect of the nature of the nanocrystalline polysaccharide (chitin or cellulose), its content (0-10 wt. %), and the nature of the polymeric matrix (guar or hydroxypropylguar) on the distribution of the polysaccharides in the polymeric matrix and the deformation–strength and sorption of the polysaccharides of the composite films were investigated. The effect of the introduction of nanocrystalline polysaccharides on the structure of three-dimensional macroporous samples of the various matrixes was studied. The obtained materials are promising for use in the food industry and in bioengineering.

Nonwoven polymer materials based on polyamide-6 coated with stainless steel that are used as electrodes to produce energy and batteries to store it were investigated. Nanofibers were prepared by capillary-free electrospinning. The metal coating was applied using vacuum magnetron sputtering. Continuous metallized nonwoven material coated with sputtered stainless steel was formed after 4-10 min of magnetron sputtering. The resistance of the metallized nonwoven material was seven orders of magnitude less than that of uncoated material and five orders less than that of heat-treated nonwoven material. It was found that vacuum sputtering of the conducting stainless-steel coating reduced the nanofiber diameter by an average of 1.5 times due to evaporation of residual solvent.

New effective nonwoven fibrous materials with bactericidal activity were electrospun from poly(3-hydroxybutyrate) and the iron(III) complex of tetraphenylporphyrin. Fiber surface defects were found to disappear if the iron(III) complex of tetraphenylporphyrin was added to the polymer solution. The supramolecular structure of fibers with encapsulated iron(III) complexes of tetraphenylporphyrin was investigated by DSC and EPR spectroscopy (probe method). It was shown that the degree of crystallinity increased sharply and molecular motion slowed in amorphous regions of the ultrathin fibers if the complex was added to the poly(3-hydroxybutyrate) matrix. The resulting fibrous materials possessed bactericidal properties and should be directly applicable to the fabrication of antibacterial and antitumor therapy systems.

Membrane-coated cloth items are very highly varied and include clothes and shoes for active vacations and tourism; special clothing for workers, firemen, and medical workers; military uniforms; and household (furniture fabrics) and technical (tents) items. They all should satisfy claimed requirements, e.g., protection from adverse environmental effects and removal from the space underneath the clothing of metabolic products and excessive moisture and heat depending on the load. The present article focused on the structural effect of an electrospun membrane and the composition of the glue layer on the operational properties of textile composites.