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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.

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Various absorption properties of papers produced from pine and birch pulps

Werner A.E., Stanisławska A.J., Świekatowski W.B.

Polish Journal of Chemical Technology

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2006

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Vol. 8, nr 4

88-90

EN

The objective of this work was to investigate absorption properties with regard to the type of base paper. Papers of different hardwood to softwood fiber ratio were prepared and coated with K bars of a different wounded wire diameter, which assures various coatings thickness. Coated papers were dried under infrared heaters and stored in constant temperature and constant humidity room. Based on curves obtained during water penetration dynamics investigation, the absorption properties were determined. Cobb index was also measured. The lowest water absorption was found for the coatings applied on papers prepared from the softwood pulp. The increased content of hardwood fibers in the pulp was identified with the increase in the absorption properties. Moreover, it was found that - regardless of the basestock type - the increased coating thickness resulted in lower water absorption as well as in the decreased absorption rate. Cobb60 index measurements confirm the results obtained from the analysis of the penetration curves. Differences in absorption properties were attributed to various characteristics in the softwood and hardwood fibers.

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Monitorowanie morfologii włókien w ciągu produkcji masy celulozowej

Wandelt P., Perlińska-Sipa K.

Przegląd Papierniczy

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2005

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R. 61, nr 7

402-409

PL

Zbadano przydatność oznaczenia właściwości morfologicznych włókien metodą komputerowej analizy obrazu do lokalizowania węzłów linii produkcji bielonej masy celulozowej siarczanowej z drewna sosnowego i brzozowego, w których włókna ulegają deformacji i ewentualnemu osłabieniu pod wpływem czynników mechanicznych lub chemicznych. Przede wszystkim dokonano przeglądu literatury na temat deformacji i uszkodzeń włókien tworzących słabe miejsca rzutujące na wytrzymałość pojedynczych włókien i papieru oraz metod ich oznaczania, przydatnych w diagnostyce ruchowej. Największy wzrost stopnia skędzierzawienia włókien i zawartości włókien załamanych stwierdzono w wysokostężeniowym stopniu bielenia tlenowego. Stwierdzono potrzebę zastosowania także kombinowanej metody oznaczania liczby słabych miejsc przypadających na statystyczne włókno, o której ostatnio pisali autorzy fińscy. Monitorowanie morfologii włókien wzdłuż całej linii produkcyjnej jest godne zalecenia, jako uzupełnienie w diagnostycznym systemie wczesnego ostrzegania dla personelu celulozowni i papierni.

EN

Applicability of an image analysis of fiber morphology in localization of points of mechanical or chemical degradation of fibers in bleached kraft pine and birch pulp production line was studied. First of all literature on fiber deformations and damages creating weak points affecting strength properties of individual fiber and paper was surveyed. A need for application of a new combined method of weak points per fiber determination proposed recently by Finnish authors was stated. The monitoring of fiber morphology along whole production line is recommended as an addition to the early-warning system for pulp and paper mill personnel.