Sub-micron and nanosized specialty fibres by electrospinning

Electrospinning is a method that can be used in preparation of many kind of functional and technical fibre in submicron and nanosized range. Functionality can be obtained, for example, by adding different kind of fillers into electrospinning and/or by heat treatment of electrospun fibres. We have demonstrated preparation of precursor fibres for carbon and ceramic (TiO2 and BN) fibres from different substances. Precursors for carbonization have been prepared using polyacrylonitrile (PAN), PAN-carbon nanofibre (CNT) composites, as well as lignin. Selected precursors were carbonized. TiO2 fibres were prepared using fluidic titanates in electrospinning with polyvinyl pyrrolidone (PVP) and forming TiO2 in heat-treatment of blend fibres in O-containing atmosphere. For BN fibre preparation B2O3 powder was mixed into electrospinning solution with different polymers. Such precursor fibres could be transformed into BN by heat-treatment in N-containing atmosphere. Properties of electrospun fibres depend on the solutions properties as well as electrospinning conditions. In composite fibre production containing solid filler the major challenge is the dispersion of filler particles. When final fibrous product is obtained using thermal treatment even more variables are affecting the properties. In this presentation precursor processing challenges and properties of selected specialty fibres are discussed. Examples of precursors and heat-treated fibres are presented in Figure 1.