Structure-Property Investigation of Knit Patterns on Mechanical, Thermal, and Moisture Properties

While recent advances in material science has expanded functionlaities of textiles, little is known about how the textile structure alone changes the response. Fabric, a 2D form of textile, is characterized with exceptionally intricate structures involves interlacing (weaving), intermeshing or interloping (kitting), fiber entangling (nonwoven), intertwining (braiding). The present work explores the structure-property relationships of different knit structures with same fiber and yarn properties; how different loop formation techniques (intermeshing or interloping) impact on the moisture and heat transfer properties of fabrics, determinants of comfortability, crucial and fundamental properties of wearable textiles. Herein, 12 types of polyester-based knit performance textiles including basic and complex knits were produced and investigated for i) bi-axial mechanical response, ii) vertical (AATCC TM197-2011e2) and horizontal moisture wicking (AATCC TM198-2011e), as well as iii) heat transfer properties using sweating guarded hotplate method (ASTM-1868). The mechanical responses have been corroborated by digital image correlation (DIC) and textile-based modelling. Results shows wicking properties of basic knit structures are better relative to complex structures; however, opposite is found in case of heat transfer. Wick runs faster along the wale (lengthwise) direction for most of the cases; nonetheless, higher wicking in course direction and few even wicking (same in both directions) are also observed, which are related to the tightness of the structure, interloping techniques, loop density, and fabric density. On the other hand, heat transfer is related to thickness of the fabric, fabric density, chances of developing entrapped air in the structure during wearing, volume and distribution of entrapped air. This paper also aims to quantify still air volume and distribution using X-ray tomography, and relates these attributes to the thermal resistance of the fabric and fit regression model to predict thermal properties, which has not been reported yet to best of the authors' knowledge. The research has high implication in technical design of apparel to tune comfort properties simply changing the fabric structure.