REGULAR CONTRIBUTED ARTICLES S. Kara 1 * , M. E. Ureyen 2 , U. H. Erdogan 1 1 Department of Textile Engineering, Dokuz Eylul University, Izmir, Turkey 2 Architecture and Design Faculty, Anadolu University, Eskisehir, Turkey Structural and Antibacterial Properties of PP/CuO Composite Filaments Having Different Cross Sectional Shapes Textile scientists make researches for producing new types of fibers as well as modifying the existing fibers to provide new raw materials for technical textile applications. The easiest way of modifying fiber physical properties is to change the cross sectional shape of a synthetic fiber. Also, composite fi- bers loaded with different kinds of additives attracted the at- tention of researchers in the last decades for functionalizing fibers. Some other methods like coating, exhausting, padding or other novel methods can be used for the same purpose. But in these methods, the functional effect is generally not durable enough against several times of washing and abra- sion. Also, these methods usually require higher consumption of water and heat when compared to composite fiber produc- tion. As a result, in this work the effect of cross sectional mod- ification and composite fiber production were combined in the same fiber. One of the most important functional properties which can be provided by composite fiber production is anti- bacterial activity. Only a few research papers were published on antibacterial additive doped polypropylene fibers. In this work cupric oxide (CuO) doped antibacterial composite poly- propylene (PP) fibers having different cross sectional shapes (circular, trilobal and triangular) were produced and the ef- fect of cross sectional shape and CuO on the antibacterial ac- tivity, structural and mechanical properties of the fibers were investigated for the first time. Cross sectional and longitudi- nal images of composite fibers were evaluated by using opti- cal microscope and scanning electron microscope (SEM). As the released content of active agent is an important parameter for the activity, durability, environmental and health effect of the product, the copper release from the fibers into the water media was investigated by inductively coupled plasma optical emission spectrometry (ICP-OES). Thermal analysis results showed that PP/CuO composite filaments having three differ- ent cross sectional shapes can be produced without any sig- nificant changes on thermal behavior of fibers. With the in- creasing content of cupric oxide, tenacities of fibers slightly decreased. Cupric oxide particles also led to some crystalli- nity changes. All of the composite fibers showed good anti- bacterial activity against Gram-negative bacterium Escheri- chia coli. 1 Introduction Today, chemical fibers are the most widely used raw materials in textile industry. They are preferred for technical applications especially where function is the primary criterion. Chemical fi- bers can be modified by several physical and chemical methods to improve their properties for new application areas in ad- vanced and functional textiles. One of the modification meth- ods is changing the cross sections of the fibers from circular to non-round shapes like trilobal, flat, hollow and triangular. Numerous papers were published about the effect of fiber cross section on polyester fiber, yarn and fabric properties such as lustre (Shin et al., 2005), handle (Tyagi and Madhusoodhanan, 2006), strength (Karaca and Ozcelik, 2007; Hasan et al., 2009a), bending rigidity (Varshney et al., 2011; Omeroglu et al., 2010), bulkiness (Varshney et al., 2014), compressibility (Varshney et al., 2011), drape (Omeroglu et al., 2011), moist- ure and liquid transfer (Das et al, 2008; Wang et al., 2008, Ha- san et al., 2009b), resilience, frictional properties, surface properties (Bueno et al., 2004; Varshney et al., 2014), structur- al properties (Takarada et al, 2001), heat and acoustic insula- tion properties (Tascan and Vaughn, 2008; Kino and Ueno, 2008), sound characteristics (Kim et al., 2003) and comfort properties (Tyagi et al, 2009; Karaca et al., 2012). Only a few research papers were published on different cross sectional shaped polypropylene fibers (Kara, 2011; Kara et al., 2012a; Ma et al., 2002; Rovere et al., 2002; Jung et al., 2010). Another method to modify chemical fiber properties is to in- corporate organic or inorganic additives into the polymer to ob- tain composite fibers. By this way, unique functional proper- ties such as conductivity, antimicrobial activity, UV stability, smell absorbing property, electromagnetic shielding, higher strength and modulus, photocatalytic effect and flame retar- dancy can be introduced to the fibers. To implement these properties; different additives such as silver (Dastjerdi et al, 398 Ó Carl Hanser Verlag, Munich Intern. Polymer Processing XXXI (2016) 4 * Mail address: Sukran Kara, Dokuz Eylul University, Engineering Faculty, Department of Textile Engineering, Tınaztepe Campus, 35397 Buca, Izmir, Turkey E-mail: sukran.kara@deu.edu.tr International Polymer Processing downloaded from www.hanser-elibrary.com by Hanser - Library on August 18, 2016 For personal use only.