A Comperative Study on the Performance of Side-by-side Hollow Bicomponent Yarns

Using hollow yarns can change and improve many qualities of fabrics including thermal, acoustic, or mechanical properties. Using technical yarns in commercial textile products has been studied extensively to bring them some sort of functionality. In this study, side-by-side 50%/50% bicomponent yarns made from different raw materials were tested and evaluated to determine their processing behaviour and performance characteristics. All yarns have co-polyester (coPET) as one component where the other component is Polyester (PET), recycled PET (rPET) and Polyamide (PA6), respectively. Afterwards, the coPET component is dissolved from all yarns by alkalization, thus making the hollow yarns, and the samples were textured by heat treatment. The mechanical and physical properties were evaluated by various tests, including unevenness, crimp testing, hollow ratio, and shear test. Their thermal and thermomechanical properties were evaluated with Differential Scanning Calorimeter (DSC) analysis and Thermal Gravimetric Analysis (TGA). Also, X-ray Diffraction Analysis (XRD) analysis was carried out in order to observe the crystalline behaviour of the samples. All evaluations were done on the non-textured and textured state of the yarns to see the effect of the heat treatment. The physical and mechanical test results revealed that despite the alkalization, the textured yarns demonstrated better strength and dimensional resistance. DSC and TGA analysis showed that the alkalization and heat treatment caused an increase in the polymer mobilization, which resulted in an increase in the decomposition enthalpy and a lower decomposition temperature. As a final note, XRD results indicated that for the PET/coPET and rPET/coPET samples, the texturization process significantly increased the crystallinity of the samples, which unexpected and therefore needs further investigation.