**7. References**


http://fiberarts.org/design/articles/mercerized.html

Biganska, O. (2002). *Etude physico-chemique des solutions de cellulose dans la Nmethylmorpholine-Noxyde.* PhD Thesis, Centre de Mise en Forme des Materiaux (CEMEF), Sophia Antipolis, France.

The unique feature of cellulosic substrates to absorb moisture from the air or absorption of water or other solution, for example sodium hydroxide, causes swelling of this substrate. Then expansion of the fibre, yarn, or fabric occurs due to the swelling in liquid media. By continuous growth of fibre, yarn, or fabric, the accessibility becomes restricted as the porosity or the inter- and intra-yarn pores and/or inter-spaces diminish. Hence, NaOH treatment influences physical properties such as stiffness, shrinkage, water retention value and wet pick-up, mechanical properties such as tension, break force, elongation, crease

Also, it was shown and discussed herein that alkalization and release during wash-off are governed by fabric structure and alkali concentration. This finding is of particular relevance for an optimized processing of fabrics from regenerated cellulose fibres. While in technical processing, materials consisting from the same type of fibre and with similar mass per area are considered to behave identical during alkalization the present results show the need for

It is obvious that the cellulose is very complex material and there is still limited knowledge available in this field rather containing more questions and uncertainties. A representative example is alkali treatment of this substrate with ongoing research more than 160 years and always some gaps within this area are recognised. In recent years, it can be seen that the field of cellulose, cellulose derivatives, or polysaccharides is expanding largely due its recognised wide potential and also its environmental benefit. Therefore, the long-term task for present and future research in cellulose is the development of novel processes which yield no or minimal ecologically harmful by-products. If these efforts are successful, cellulose will maintain and strengthen its position as a renewable and environmentally beneficial, industrially important raw material competing with synthetically produced

The authors are grateful to the Amt der Vorarlberger Landesregierung, Europäischer Fonds für Regionale Entwicklung (EFRE), and COMET K-project ''Sports Textiles'' project number 820494 funded by Die Österreichische Forschungsförderungsgesellschaft (FFG), for their

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**5. Conclusion** 

recovery angle and mass loss.

individual process adaptation.

polymers.

**6. Acknowledgment** 

**7. References** 

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**0**

**8**

<sup>1</sup>*Turboinštitut*

*Slovenia*

<sup>2</sup>*University of Ljubljana*

**Novel Theoretical Approach to the Filtration of**

The motivation for this work comes from studying the composition of a medical face mask made of non woven fabrics and the mechanisms of filtrations inside the mask. Present medical mask filters passing air with the maximum efficiency of 99.97%, which might be seen as excellent. Main question is: "What presents this 0.03%?" If an aggressive virus is found in

The filtration mechanism in a non woven fabric is a complex process. It is obvious that air passing through a non woven fabric has to go through voids in the fabric. In order to understand the filtration mechanism, it is essential to be able to define fabrics porosity parameters, the nature of the air flow through voids in the fabric and the behaviour of the

The classical theory of filtration is based on a single fibre in the fluid flow; Sharma (2000),Brown (1993), and Hutten (2007). It neglects neighbouring fibres and thus all porosity parameters. It was reasonable simplification due the fact that no easy method that would be reliable at the same time did exist until J-method for assessing the flat textiles porosity was introduced in Jakši´c & Jakši´c (2007) and Jakši´c & Jakši´c (2010). J-method enables us to determine all relevant porosity parameters, which makes this approach to filtration possible. Medical face masks, which are made of textile fibres, are light, easy to use, relatively low-cost, and very efficient in combating air-borne infections. The mask design should provide tight fit to the skin of a face in order to ensure that air flows only through the mask. The design of the mask should also ensure filtration, not only dust particles, but also microbes and viruses. The masks are meant for a single use to avoid saturation of a mask. They are also suitable for use

The mask composition must be proper regarding its use. The filtering layer must be protected with additional layers at its side faced towards a subject's face and outside side. Voids (pores) in the inner layer, which is actually filter passing air, should not lead air from the outer side to the inner side of the layer directly, as a channel. The dust particles, microbes and viruses might penetrate a mask designed in that way by being trapped in the unobstructed air flow. Pores in the inner layer, that enables air flow through mask, should be small enough and winded like a channel frequently changing its direction, in order to ensure maximum filtering efficiency.

this tiny share, the effectiveness of the mask would be questionable.

**1. Introduction**

nano-particle caught inside the flow.

in a dust environment until saturation of a mask.

**Nano Particles Through Non-Woven Fabrics**

Nikola Jakši´c1 and Danilo Jakši´c2

