Some properties of the structure of polyamide (PA) and polypropylene (PP) hollow fibers were investigated in a theoretical fashion. These fibers were simultaneously compared with solid fibers. The structural indices of the hollow fibers, that is, the wall thickness and inner diameter, were systematically examined with the aim of determining their effect on the four conventional structural indices suitable for hollow fibers and for solid fibers. The fiber outer diameter and fiber outer lateral area were examined as well, and the ratio of the fiber outer lateral area to the fiber whole volume and the ratio of this area to the fiber mass were considered. Under assumptions about the fixed level and equal values of the linear density of PA and PP fibers, comments on the aforementioned effect were presented. The structural properties of these fibers with different wall thicknesses and inner diameters were examined.

Purpose – The purpose of this paper is to investigate the physical properties of smart aromatherapic ramie/cotton terry fabrics containing microcapsules (MC) with essential Eucalyptus oil. Design/methodology/approach – Terry fabrics are manufactured by changing the weft density. The air permeability is determined for grey and microencapsulated textile. The factorial designs are made. For informative experiment the linear type of regression is analysed. Development of physical properties of microencapsulated terry fabrics is discussed. Findings – The air permeability of aromatherapic terry fabrics is determined. All statistical analysis is performed. Appropriate conclusions about the influence of fabric’s structure and microencapsulating process on terry fabric quality are made. Originality/value – To date there are no investigations concerning terry textiles with fragrance MC. This study developed analysis and empiric mathematical equations suitable for evaluating and designing terry fabrics with the air permeability required. Assessment of the influence of fabric’s weft density and binder concentration for the air permeability of terry textile is proposed.

This study deals with numerical simulation of structure of covered yarns produced on a double covering machine. Four manufacturing parameters of covered yarns such as delivery speed of covered yarn, rotational speed of two hollow spindles, and core stretch ratio during wrapping were used to simulate coil length indices of both covering components. Coefficient of evenness of semi-manufactured product as a function of delivery speed of covered yarn and rotational speed of first hollow spindle was also computed. The influence of the above-mentioned process variables on the geometry of covering components was shown by means of analysis of corresponding relationships. To evaluate the intensity effect of each variable, the comparable partial differences of the proposed functions were computed. The computations were made for covered yarn structures composed of polyurethane elastomeric multifilament core wrapped with two viscose (CV) multifilament covering yarns.

No abstract

While the functional compound Polycom JB 7100 is often introduced into polyolefins as a modifier, processing aid and bonding agent, little is known about its influence upon the basic structure and mechanical properties of composite tape yarns. Polycom JB 7100 is a master bath of inorganic materials and polyolefins. To show the effects of different amounts (0 -6 wt%) of this additive in polypropylene (PP)-based composite tape yarns, experiments were made without changes to other additive portions and at constant process parameters. The linear composition-property relations showing the effects of portions of the variable component on the changes in morphology, geometrical properties and tensile behaviour were obtained. Tape yarns, in which a portion of PP was replaced by the functional compound Polycom JB 7100, had tensile properties about 2 -9% lower than the yarns without this additive, whereas the values of width, thickness and linear density after applications of the additive were about 3 -4% greater if compared with those of the basic sample.