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Preparation of carbon nanotube embedded in polyacrylonitrile (PAN) nanofibre composites by electrospinning process

Pilehrood M. K., Heikkilä P., Harlin A.

Autex Research Journal

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2012

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Vol. 12, no. 1

1--6

EN

Polyacrylonitrile (PAN) nanofibres and carbon nanotube (CNT) reinforced PAN nanofibres were successfully electrospun. A polymer plasticiser, ethylene carbonate (EC), was added into the PAN/CNT solutions. The average diameter of the fibres varied between 80 and 240 nm. This study investigated the effects of polymer concentration, CNT and EC on the morphological characteristics of electrospun PAN fibres. Electrospinning parameters were set at constant values to prevent their mutual influences on the resultant morphology. It was observed that increasing the polymer concentration led to a reduction of beads density and an increase in the diameter of the PAN nanofibres. The fibre diameters also increased as a result of the addition of CNTs below the electrical percolation threshold. It was found that the inclusion of EC permits changes in the morphological characteristic of the PAN/CNT nanocomposite fibre regardless of the effects of its conductivity and viscosity.

2

Press Felts Coated with Electrospun Nanofbres

Hakala T., Heikkilä P.

Fibres & Textiles in Eastern Europe

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2011

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Vol. 19, no. 1 (84)

89-93

EN

Press felt specimens were coated with nanofbres using the electrospinning process. The coating weight of the nanofbre layer and the spinning distance were varied in order to study the homogeneity and coverage of the nanofbre web. The specimens were studied by scanning electron microscopy (SEM) and laser proflometry to understand how the nanofbre web attaches to the press felt, and how nanofbres improve the surface smoothness. The surface pore size, thickness, weight per unit area and air permeability of the specimens were measured. The surface smoothness improved and the air permeability decreased slightly. The adhesion of the nanofbre web to the press felt and the mechanical strength of the nanofbre web were poor. The study showed, however, that the combination of electrospinning and felt structures has the potential to enhance press felt performance.

3

Fast and efficient surface treatment for nonwoven materials by atmospheric pressure plasma

Väänänen R., Heikkilä P., Tuominen M., Kuusipalo J, Harlin A.

Autex Research Journal

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2010

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Vol. 10, no. 1

8--13

EN

Plasma treatments can be used for the nano-scale surface modification of different materials including nonwovens. Penetration of plasma into solid matter is very limited, but it can penetrate into porous structures. Therefore plasma can be used to modify not only the outer surface, but also the surfaces of fibres within and the other side of the porous structure of nonwoven material. The purpose of this study was to examine the feasibility of continuous atmospheric plasma treatment for the modification of porous nonwoven materials. Firstly, the penetration of plasma through layered, porous samples, and secondly, the effect of the plasma exposure time on the surface properties and mechanical properties of the samples were studied. We found that the plasma penetrated through three nonwoven layers. It also seemed that the plasma was retained inside the samples for a while after initial exposure, thus increasing the effective exposure time. An increase of exposure time further by controlling line speed did not have significant influence on the efficiency of the treatment. The mechanical properties of the material were not prominently affected by the treatment. Our results suggest that it is possible to conduct twosided plasma treatment on porous nonwoven materials as a continuous process with a speed feasible to be combined with conventional textile processing.

4

Electrospun nanofibers prepared by two methods: in situ emulsion polymerized PVA/nano TiO2 and mixing of functional-PVA with nano TiO2

Ristolainen N., Heikkilä P., Harlin A., Seppälä J.

Autex Research Journal

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2008

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Vol. 8, no. 2

35--40

EN

Poly(vinyl alcohol)/nano-sized titanium dioxide (PVA/nanoTiO2) water dispersions were electrospun in order to prepare networks of polymer composite nanofiber for coating applications. In particular, the effect of the functionalization of the polymer matrix, coating of the filler particles, and the preparation method of the polymer dispersions on the nanoparticle distribution along the resulting fibers were studied. The dispersions were prepared using two different techniques: batch in situ emulsion polymerization and mixing methods. Differently coated hydrophilic nanoTiO2 particles were used on one hand, and on the other, pure PVA and carboxyl- and silanol-functionalized PVAs were used. Dispersion properties were assessed by measuring viscosity and estimating the degree of homogeneity before electrospinning. The structure of the electrospun fibers was studied using scanning electron microscopy and elemental analysis. It was observed that the dispersion properties differed substantially depending on the types of polymer and filler particles used. Electrospinning succeeded in forming continuous fibers instead of separate droplets with all except one type of PVA/nanoTiO2 dispersions. It was confirmed that the resulting fibers and droplets contained nanoTiO2 particles. For the in situ polymerized dispersions the filler distribution in the resulting fibers was strongly influenced by the nanoparticle coating. In the mixing method, the resulting nanoparticle distribution was affected primarily by the polymer type used, and the role of the nanoparticle coating was not important.