Gulay Ozcan

Antibacterial activity of PA6/ZnO nanocomposite fibers

In this study, ZnO-loaded PA6 nanocomposite preparation and its antibacterial activity are investigated. This work aims to study the effect of the sizes and amount of the ZnO nanofiller on the antibacterial, mechanical, and thermal properties of the PA6/ZnO nanocomposites. The melt intercalation method is applied to prepare polyamide 6 (PA6) nanocomposite fibers, including 0, 0.5, 1, 3, 5 wt % zinc oxide (ZnO), using a laboratory-scale compounder. The antibacterial activity of the fibers against Staphylococcus aureus (ATCC 6538) as a gram positive bacterium and Klebsiella pneumoniae (ATCC 4352) as a gram negative bacterium is determined according to ASTM E 2149-0. Mechanical and thermal characterization tests are performed according to relevant standards (ASTM D7426-08, ASTM E1131-08, ASTM D3822-07; DSC, TGA, tensile tests). It is found that the dispersion of the ZnO particles within the PA6 matrix is homogenous according to scanning electron microscopy results. Antibacterial activity tests show that PA6/ZnO nanocomposite fibers exhibit antibacterial efficiency related to their nanoparticle contents. An increase in the amount of nanoparticles causes an increase of the antibacterial activity of the fibers. On the other hand, mechanical and thermal characterization tests show that the addition of ZnO nanoparticles does not affect the strength and thermal properties of the nanocomposites for these loadings.

An Investigation of UV Protection of Swimwear Fabrics

The increased incidence of skin cancer in recent years has resulted in a repeated call for the prevention of UV radiation damage and so investigation on the effects of UV radiation has become more and more important for researchers. In an effort to reduce solar UV radiation exposure, one important method is to use UV-protective textiles. Swimwear fabrics are mostly exposed to sunlight during the summer days, so that it is expected that they provide more UV protection than other textiles. In this study, swimwear fabrics with the same knitting construction and different fiber composition (80% PET+20% /Elastane, 80% PA+20% Elastane) were treated with suitable dyestuffs and UV absorber agents at different concentrations. Then, all the treated swimwear fabrics were tested for UV absorbance (AS/NZS 4399), color fastness to rubbing (EN ISO 105X12), light fastness (TS 1008 EN ISO 105-B02), color fastness to perspiration (acidic and basic-TS EN ISO 105 E04), color fastness to sea water (EN ISO 105 E02), and color fastness to chlorinated water (EN ISO 105 E03) to evaluate the effect of their treatment parameters (such as UV absorber agent, dye concentration) on the UV protection characteristics of the swimwear fabrics.

Performance Evaluation of Water Repellent Finishes on Woven Fabric Properties

In this study, plain woven fabrics in two blends were chosen to investigate the effects of water repellent finishes on woven fabric properties. The fabrics were treated with different types of water repellents at different concentrations. The levels of water repellency of the fabrics were measured in accordance with the AATCC 22 (1996) spray test method. To evaluate the effect of water repellent finishes on the woven fabric properties, breaking strength, abrasion resistance, pilling, light fastness, washing and perspiration tests of the fabrics were performed using relevant British Standards, ASTM and ISO standards. Wetting time of the fabrics was also measured before and after abrasion, washing and perspiration tests to evaluate performance and durability of the treatments. The results, evaluated using SPSS statistical program, showed that the water repellent finish type and concentrations were very important parameters to obtain water repellent fabric having acceptable use properties.

Antimicrobial activity of poly(l-lactide acid)/silver nanocomposite fibers

Silver (Ag) nanoparticles (NP) and poly(lactide acid) (PLA) granules were microcompounded to form a nanocomposite. A series of PLA nanocomposite fibers containing, respectively, 0, 0.5, 1, 3 or 5 wt% Ag were produced and their antimicrobial activity against Gram-negative and Gram-positive bacteria evaluated. It was found that the PLA/Ag nanocomposite fibers exhibited increased antimicrobial activity, depending on the filler content. On the other hand, mechanical and thermal characterization tests, including thermogravimetric analysis, differential scanning calorimetry and tensile testing, showed that increasing concentrations of Ag hindered the mechanical properties of Nanocomposites due to partial agglomeration, leading to the generation of flaws. The crystallinity of the fibers was found to decrease by about 23% if the Ag content was increased to 5%. This could be attributed to a more rapid cooling rate resulting from the high thermal conductivity of the Ag particles.

Impact of Finishing Processes on Flame Resistance of Knitted Fabric

In this study, knitted fabrics are chosen to investigate the effect of their finishing properties on flame resistance. Finishing processes (bleaching, dyeing, and some chemical additives used for bleaching and dyeing) that affect fabric flammability are defined and an experimental program is followed. The level of flammability of the treated fabrics is measured in accordance with the BS 5438 vertical flammability test method because its results are very similar to real fabric burning behavior. Finally, experimental results are evaluated according to a statistical analysis with the SPSS program, and how and at which level chemical parameters affect knitted fabric burning behavior is defined.

In vitro assessment of antimicrobial polypropylene/zinc oxide nanocomposite fibers

A series of polypropylene (PP) nanocomposite fibres containing respectively 0, 0.5, 1, 3, and 5 wt% ZnO nanoparticles (NPs) were prepared by melt spinning. The antimicrobial activity of these fibers against Staphylococcus aureus (ATCC 6538) as a Gram-positive bacterium and Klebsiella pneumoniae (ATCC 4352) as a Gram-negative bacterium was evaluated. It was confirmed by scanning electron microscopy that the dispersion of the NPs within the PP matrix was homogeneous. Although such homogeneity the fibers are unable to exhibit antimicrobial activity. The absorption properties of the fibers was then investigated and found to be inadequate, so cold plasma and chemical finishing were applied to improve their absorptivity. After this treatment the PP/ZnO nanocomposite fibers exhibited increasing antimicrobial effectiveness with filler content. In addition, mechanical and thermal characterization tests showed that increasing concentration of ZnO–NPs improved the mechanical properties of the fiber due to the interface between the matrix and the nanoparticles sharing the stress. The crystallinity of the fibers was found to decrease by about 7% as the level of ZnO increased to 5%. This was attributed to the more rapid cooling experienced in the presence of ZnO particles of high thermal conductivity.

In vitro assesment of antimicrobial activity and characteristics of polyamide 6/silver nanocomposite fibers

In this study, the preparation method and characteristics of silver (Ag) nanoparticle (NP) loaded polyamide 6 (PA6) nanocomposite and its antimicrobial activity against Klebsiella pneumonia and Staphylococcus aureus were investigated. The melt intercalation method was used to prepare a series of PA 6 nanocomposite fibers containing, 0; 1; 3; 5 % (wt.) Ag. PA6/Ag nanocomposite fibers exhibit increased antimicrobial efficiency with the increase of nanoparticle contents. On the other hand, thermal characterization tests show that the increased concentration of Ag nanoparticles reduces the mechanical properties due to their partial agglomeration leading to flaw generation. The crystallinity of the fibers was found to decrease about 10 % with increase of Ag to 5 %. This was attributed to faster cooling rate experienced in the presence of high thermal conductivity Ag particles.

Effect of Gray Fabric Properties on Flame Resistance of Knitted Fabric

In this study, knitted fabrics that have been used extensively in recent years are chosen to investigate the effects of their properties on flame resistance. Physical parameters (fiber type and composition, yarn count, yarn twist coefficient, fabric design, weight per unit area, air permeability, fabric thickness, cover factor, loop density) that affect fabric flammability are defined and an experimental study is designed. The burning behavior of the all fabrics is evaluated using the BS 5438 vertical flammability test method because its results are very similar to real fabric burning behavior and it is more responsive than other test methods. Finally, experimental results are evaluated according to a MANOVA analysis using an SPSS statistical program. How and at which level knitted fabric param eters affect a fabrics burning behavior is defined, and regression models of these parameters are obtained. Using these regression models, the burning behavior of knitted fabrics is evaluated, and it is possible to rank them according to their burning character istics.

Anatase titanium dioxide loaded polylactide membranous films : preparation, characterization, and antibacterial activity assessment

In this study, the preparation method and characteristics of anatase titanium dioxide (TiO2) nanoparticle-loaded polylactide (PLA) films and their antibacterial efficacy against Klebsiella pneumoniae (ATCC 4352) and Staphylococcus aureus (ATCC 6538) bacterium were studied. A series of PLA nanocomposites containing, respectively, 0, 1, and 5% (wt.) titanium dioxide (TiO2) nanoparticles were prepared by melt intercalation method. The effect of TiO2 nanoparticles on the thermal and mechanical characteristics of the films was determined. Thermal analysis showed that the glass transition temperature, crystallization temperature, melting temperature, and decomposition temperatures (Td0.5 and Td0.05) decreased with the filler content. The results obtained from tensile tests showed that TiO2 nanoparticles reduced the mechanical properties and moduli of the PLA films. On the other hand, the water absorption properties of the nanocomposite films increased with the addition of nanoparticles and nanocomposite films exhibited bacteriostatic and limited bactericidal efficacy according to AATCC 147. Consequently, nanocomposite films may be good materials for medical applications due to their membranous properties.

Polimer Esaslı Nanokompozitler ve Tekstil Uygulamaları

Production and use of nanocomposites increased with the development of nanotechnology. Polymer nanocomposites are the most widely used nanocomposite types. They are obtained by mixing polymer melt and nano fillers such as fibers particles and tubes. With the use of polymer nanocomposites, it is possible to produce more strong, durable and functional products. With the use of nanocomposites in the textile industry, textile products with antimicrobial, UV-resistant, high-strength, electrically conductive, dirt-resistant properties has been able to produce. In this study, nano materials used in the production of nanocomposite will be introduced and their effects on the nanocomposites will be discussed. Also by comparing the production methods of nanocomposites, the production methods will be explained how to alter application areas of nanocomposites.