Filip Sanetrnik

Polyamic acid nanofibers produced by needleless electrospinning

The polyimide precursor (polyamic acid) produced of 4, 4′-oxydiphthalic anhydride and 4, 4′-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143-470nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support--namely filtration effectivity and pressure drop--were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

Preparation of antibacterial nanofibre/nanoparticle covered composite yarns

The antibacterial efficiency of nanofibre composite yarns with an immobilized antibacterial agent was tested. This novel type of nanofibrous composite material combines the good mechanical properties of the core yarn with the high specific surface of the nanofibre shell to gain specific targeted qualities. The main advantages of nanofibre covered composite yarns over the standard planar nanofibre membranes include high tensile strength, a high production rate, and their ability to be processed by standard textile techniques. The presented paper describes a study of the immobilization of an antibacterial agent and its interaction with two types of bacterial colonies. The aim of the study is to assess the applicability of the new composite nanomaterial in antibacterial filtration. During the experimental tests copper(II) oxide particles were immobilized in the polyurethane and polyvinyl butyral nanofibre components of a composite yarn. The antibacterial efficiency was evaluated by using both Gram-negative Escherichia coli and Gram-positive Staphylococcus gallinarum bacteria. The results showed that the composite yarn with polyvinyl butyral nanofibres incorporating copper(II) oxide nanoparticles exhibited better antibacterial efficiency compared to the yarn containing the polyurethane nanofibres. The nanofibre/nanoparticle covered composite yarns displayed good antibacterial activity against a number of bacteria.

Investigation on acoustic behavior and air permeability of struto nonwovens

This work deals with the study of acoustic performance of struto nonwovens and their relation to fabric air permeability. In order to achieve the objective of the research, sound absorption coefficient of struto nonwovens was determined via impedance tube method, the average value of sound absorption coefficient (α̅) was calculated. Air permeability of struto nonwovens was examined by using FX3300 Textech Air Permeability Tester. Results showed that struto nonwoven exhibited good absorption ability at frequency bands 3000-6400 Hz while it was ineffective for frequency lower than 3000 Hz. Struto nonwovens with high GSM and fabric thickness showed better acoustic performance and lower air permeability. It was observed that α̅ was inversely proportional to air permeability, with correlation coefficient 0.95. It was concluded that air permeability can be used as a criterion of sound absorption behavior of struto nonwovens. A lower air permeability suggests a better sound absorption performance for struto nonwoven fabrics.

Nanofibrous Composite Materials Integrating Nano/Micro Particlesbetween the Fibres

This article deals with the continual incorporation of particles by the ultrasonic dispersion in situ into a nanofibrous matrix produced by the electrospinning process. The new technology is based on the use of the needleless electrospinning method in combination with the ultrasound-enhanced dispersion of sub-micro or micro particles, which are deposited between nanofibres onto the support material. The main advantage of this technology is the independence of particle-incorporation of the electrospinning process. The particles are trapped between the fibres and they remain uncovered by polymer, thus maintaining all their active properties. Such materials can be cut with scissors without the particles being released. In this paper the authors present figures from scans of the electron microscopy of the newly-designed nanocomposite material and its morphological analysis, such as the particle distribution. The material was used as a sorbent of bis(2-chlorethyl) sulfide (mustard gas) with a sorption time greater than 240 minutes. Such material has been developed to be used for protection against chemical warfare agents; yet, it can be employed for several other applications depending on the powder material dispersed onto the nanofibrous layer.