Wyniki wyszukiwania - BazTech

1

Prediction of the Porosity of Barrier Woven Fabrics with Respect to Material, Construction and Processing Parameters and Its Relation with Air Permeability

Malik S. A., Kocaman R. T., Gereke T., Aibibu D., Cherif C.

Fibres & Textiles in Eastern Europe

|

2018

|

Vol. 26, no. 3 (129)

71--79

EN

Porosity is one of the most important characteristics of fabrics that dictate the permeability and retention properties of fabrics. Several technical uses require textiles with a combination of definite permeability and retention properties. Besides filtration, surgical textiles require these contrary properties to offer an effective barrier against particle laden fluids, such as bacteria and viruses, together with added wearer comfort. Pore size and pore size distribution are important characteristics to determine the permeability and retention behaviour of multifilament barrier textiles by influencing the effective porosity, which can be tailored according to end use requirements by material, weave construction and processing factors. The present research was aimed at developing the relationship that material, construction and loom parameters have with porosity in terms of the mean pore size and mean flow pore size of the fabric, and thereby with air permeability. To map such nonlinear complex relations, an artificial neural network (ANN) was employed. From the findings, it was observed that the porosity of barrier fabrics can be predicted with excellent accuracy using an ANN.

PL

Porowatość jest jedną z najważniejszych cech tkanin, które decydują o przepuszczalności i właściwościach retencyjnych tkanin. Zastosowania techniczne wymagają tekstyliów z kombinacją określonej przepuszczalności i właściwości retencyjnych. Oprócz filtracji, tekstylia chirurgiczne muszą charakteryzowac się właściwościami zapewniającymi skuteczną barierę przeciwko płynom z cząstkami objętościowymi, takim jak bakterie i wirusy oraz zapewniać komfort użytkowania. Wielkość porów i rozkład wielkości porów są ważnymi cechami określającymi przepuszczalności i zachowanie retencyjne tkanin barierowych wielowłókienkowych. Przeprowadzone badania miały na celu rozwinięcie związku pomiędzy parametrami materiału i konstrukcji z porowatością w kategoriach średniej wielkości porów, a tym samym z przepuszczalnością powietrza. Aby zmapować takie nieliniowe złożone relacje, zastosowano sztuczną sieć neuronową (ANN). Z ustaleń zaobserwowano, że porowatość tkanin barierowych można przewidzieć z doskonałą dokładnością za pomocą SSN.

2

New Image Analysis Method for Determination of the Inter-Fibre Pore Size Intensity of Polyester Woven Barrier Fabrics

Kocaman R. T., Aibibu D., Cherif C.

Fibres & Textiles in Eastern Europe

|

2018

|

Vol. 26, no. 4 (130)

67--74

EN

Porosity is an important characteristic of a filter textile, which affects permeability and retention properties. Determination of the inter-yarn and inter-fibre pore sizes of barrier textiles is also required to assess the filter behaviour of these textiles. In this study, a software tool was developed to detect the inter-fibre pore size distribution and pore size intensity of multifilament woven barrier fabrics using cross-section images. Fabrics were chosen according to their fabric construction parameters, such as the fabric index, weft yarn filament fineness and weft yarn structure (flat or textured).Microscopic cross-section images of weft yarns were taken, processed to binary images, and analysed with respect to the pore size distribution, number of pore lengths and pore intensity. It was also analysed how the fabric index; filament cross-section and filament fineness affect the inter-fibre pore lengths and separation level proposed. It was found that weft yarns with wider lengths and lower height showed wider inter-fibre pores. Inter-fibre pores decreased with a decrease in filament fineness. Moreover, the separation level proposed deviated from the 90% level depending on the fabric index. This deviation was very small in samples with reduced filament fineness and textured samples. The separation level proposed will be useful to understand the effect of fabric construction parameters to obtain targeted properties regarding inter-fibre and inter-yarn pore size.

PL

Porowatość jest ważną cechą tkanin filtracyjnych, która wpływa na przepuszczalność i właściwości retencyjne. Niezbędne do oceny zachowania filtrów jest określenie wielkości porów w przędzy i między włóknami. W badaniu opracowano narzędzie programowe do określenia rozkładu wielkości porów między włóknami i ich intensywności z wykorzystaniem przekrojów poprzecznych w przypadku tkanin barierowych. Tkaniny zostały wybrane zgodnie z ich parametrami konstrukcyjnymi, takimi jak indeks tkaniny, próba włókna nitki i struktura przędzy wątku (płaska lub teksturowana). Wykonano mikroskopowe obrazy przekroju nitek wątku, przetworzono je na obrazy binarne i analizowano pod względem rozkładu wielkości porów, liczby długości porów i intensywności porów. Przeanalizowano również, w jaki sposób indeks tkaniny, przekrój poprzeczny włókna i drobnoziarnistość wpływają na proponowane długości porów międzywłókienkowych i poziom separacji. Stwierdzono, że pory między włóknami zmniejszyły się wraz ze zmniejszeniem rozdrobnienia włókien. Ponadto proponowany poziom separacji odbiegał od poziomu 90% w zależności od indeksu tkaniny. Odchylenie to było bardzo małe w próbkach o zmniejszonej próbie rozdrobnienia i teksturowanych.

3

Pcl/Chitosan Blended Nanofibrous Tubes Made by Dual Syringe Electrospinning

Hild M., Al Rez M. F., Aibibu D., Toskas G., Cheng T., Laourine E., Cherif C.

Autex Research Journal

|

2015

|

Vol. 15, no. 1

54--59

EN

3D tubular scaffolds made from Poly-(Ɛ-caprolactone) (PCL)/chitosan (CS) nanofibres are very promising candidate as vascular grafts in the field of tissue engineering. In this work, the fabrication of PCL/CS-blended nanofibrous tubes with small diameters by electrospinning from separate PCL and CS solutions is studied. The influence of different CS solutions (CS/polyethylene glycol (PEO)/glacial acetic acid (AcOH), CS/trifluoroacetic acid (TFA), CS/ AcOH) on fibre formation and producibility of nanofibrous tubes is investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is used to verify the presence of CS in the blended samples. Tensile testing and pore size measurements are done to underline the good prerequisites of the fabricated blended PCL/ CS nanofibrous tubes as potential scaffolds for vascular grafts. Tubes fabricated from the combination of PCL and CS dissolved in AcOH possesses properties, which are favourable for future cell culture studies.

4

Pure chitosan microfibres for biomedical applications

Toskas G., Brünler R., Hund H, Hund R D, Hild M., Aibibu D., Cherif C.

Autex Research Journal

|

2013

|

Vol. 13, no. 4

134--140

EN

Due to its excellent biocompatibility, Chitosan is a very promising material for degradable products in biomedical applications. The development of pure chitosan microfibre yarn with defined size and directional alignment has always remained a critical research objective. Only fibres of consistent quality can be manufactured into textile structures, such as nonwovens and knitted or woven fabrics. In an adapted, industrial scale wet spinning process, chitosan fibres can now be manufactured at the Institute of Textile Machinery and High Performance Material Technology at TU Dresden (ITM). The dissolving system, coagulation bath, washing bath and heating/drying were optimised in order to obtain pure chitosan fibres that possess an adequate tenacity. A high polymer concentration of 8.0–8.5% wt. is realised by regulating the dope-container temperature. The mechanical tests show that the fibres present very high average tensile force up to 34.3 N, tenacity up to 24.9 cN/tex and Young’s modulus up to 20.6 GPa, values much stronger than that of the most reported chitosan fibres. The fibres were processed into 3D nonwoven structures and stable knitted and woven textile fabrics. The mechanical properties of the fibres and fabrics enable its usage as textile scaffolds in regenerative medicine. Due to the osteoconductive properties of chitosan, promising fields of application include cartilage and bone tissue engineering.

5

Pure chitosan and chitsoan/chitosan lactate blended nanofibres made by single step electrospinning

Cheng T., Hund R D, Aibibu D., Horakova J., Cherif C.

Autex Research Journal

|

2013

|

Vol. 13, no. 4

128--133

EN

A single step electrospinning of chitosan and chitosan derivative-chitosan lactate nanofibres was studied in this paper. Chitosan was dissolved into acetic acid to produce structure-stable nanofibres. The effect of chitosan concentration and the content of acetic acid on the fibre diameter and morphology of nanofibres were studied in detail. The dynamic viscosity and surface tension of the electrospinning chitosan solutions were systematically studied as well. Based on the fundamental study on electrospinning chitosan in acetic acid, a chitosan derivative, chitosan lactate, was added to produce nanofibre in a pH-friendly aqueous environment. Chemical and morphological analyses demonstrated that chitosan lactate will positively influence the formation of nanofibres in higher pH condition although the morphology should be improved.

6

Modeling and CFD-simulation of woven textiles to determine permeability and retention properties

Rief S., Glatt E., Laourine E., Aibibu D., Cherif C., Wiegmann A.

Autex Research Journal

|

2011

|

Vol. 11, no. 3

78--83

EN

The previous paper (No. 2, Vol. 12-2011) [1] were analyzed the weave and construction parameters of high density woven fabric and their influence on the pore morphology, which directly effects the functional properties such as permeability and retention. The analysis encompassed physical and optical methods of testing. In this paper, newly developed methods, tools and programs will be presented for virtual imaging of the multi-filament woven fabric geometry with pore structure used to determine permeability and retention properties. Two methods are applied for the generation of virtual fabric. One method involves developing software that is able to model woven fabric in new condition from a series of realistic input parameters. In this step, deterministic and stochastic methods are combined to create the fabric’s geometry. The other method involves reconstruction/generation the 3D woven geometry from sequences of 2D cross section images. The results prove that the 3D pore morphology of high density multi-filament fabric can be illustrated in correlation of the woven construction parameters. The developed methods for modeling and the CFD simulation of woven fabric build an important basis for determining the mechanical flow properties such as permeability and retention characteristics of filters and barrier textiles. Additionally, the effects of mechanical loads on the fabric morphology and on the permeability values will be analyzed by applying uniaxial and biaxial tensile loads to the fabric. The tests provide the basis for a realistic prediction to the effects of the machine and construction parameters on the fabric properties and the resulting permeability and retention. These predictions can aid in analyzing the suitability of a fabric for a specific application.

7

Barrier effect of woven fabrics used for surgical gowns

Aibibu D., Lehmann B., Offermann P.

Autex Research Journal

|

2003

|

Vol. 3, no. 4

186--193

EN

Surgical gowns must have a barrier effect between the sources of infection and the user (i.e. a healthy person), as well as good wearing comfort. They are often made of woven polyester fabrics. Different fabric constructions are available for this purpose; these are evaluated with reference to their barrier properties. We present an optical method of obtaining cross-section figures of woven fabrics. The fabric is cut in warp and weft directions, and embedded perpendicularly in a cylindrical sample carrier using an epoxy resin. After the manufactured samples have hardened, they are smoothened and polished. Subsequently, images of the cross-sections of the fabrics are obtained by using an optical microscope linked to a digital camera and a computer. The images show the microstructure of the woven fabrics, i.e. the size and distribution of the pores in the filament yarn, and between the filament yarns with respect to the fabric weave and yarn density. The porosity is determined by image analysis methods using ImageC ® by Aquinto. The distributions of the width of the pores and of the pore areas are calculated. Pore channels are shown. The results of structural barrier effect are compared with the results of penetration tests. Synthetic blood or particle-loaded liquids containing microspheres comparable with the sizes of bacteria are used. The time necessary to soak the fabric with liquids or the contamination on the back of the fabric is determined.