Hybrid knitted fabric for electromagnetic radiation shielding

Today we can’t imagine our life without electricity and technology, transport and television. In the information age, computers, the Internet, cell phones, and smartphones are helpers for everyday needs. However, our environment and comfortable living in it can be detrimental to our health. It is hard to realize the fact that such a global technical breakthrough has hit human health. Exposure to electromagnetic radiation could lead to changes in the structure of nerve cells and blood formulas, deformation of the circulatory system, pathology of the endocrine system, decreased immunity, and so on. Nowadays the development of innovative textiles with electromagnetic radiation shielding is a relevant topic that promotes the creation of a flexible protective screen for the human being and various electronic devices. Textiles themselves do not protect against electromagnetic radiation; however, the textiles can be successfully converted into protective material after changing the raw material composition, creating a new production process, or adapting technologies that can make them electrically conductive. Basic methods of textile producing such as weaving, knitting, non-weaving, or their combination can be used to make electromagnetic shielding fabric. In this study, the knitting on 8-gauge flat-bed machine has been chosen as main technology. The metal wire (stainless steel: 0.12 mm) is used separately or together with 10 × 2 tex cotton yarn. Two sets of samples with different interloopings are produced which differ by steel percentages and positioning in the structures. Electromagnetic shielding effectiveness of textile samples (dB) was measured according to ASTM 4935-10 on frequency range 30 MHz–1.5 GHz. It is concluded that the positioning of the metal components in the knitted structure is the main factor determining the shielding ability. The half Milano rib knitted structure demonstrates the highest shielding efficiency.