Characterization and comparison of properties of cryogenic conditioned CNT reinforced thermoset (epoxy) and thermoplastic (poly vinyl alcohol) composite yarns

Carbon nanotube (CNT) fiber/yarn reinforced composites are considered as a new generation of advanced materials for applications in aerospace and space industry. In this study, two types of CNT composite yarns were produced by twisting CNT films and infiltrating with thermoset epoxy (EP) and thermoplastic poly vinyl alcohol (PVA) resins. The tensile strength of CNT/PVA and CNT/EP composite yarn was 409.91 MPa and 206.87 MPa, much higher than that of pure CNT yarn (129.94 MPa). After mono-cryogenic condition, the mechanical and electrical properties of CNT/EP and CNT/PVA composite yarns were both enhanced due to the structure reorder of the CNT bundles and improvement of interfacial bonding. However, after 60 times cyclic-cryogenic conditions, CNT/EP composite yarn showed a ∼10% degradation of tensile strength; while CNT/PVA composite yarn exhibited 6% increment. This study provides fundamental data of the CNT reinforced thermoset and thermoplastic composite yarns for their practical applications in cryogenic environment.

Preparation of the polyester/cotton composite yarn with alternating segmented structure and interval color via a promising physical spinning approach

Herein, a novel kind of composite yarn with alternating segmented structure and interval color has been prepared based on a ring spinning approach. By adjusting the relative motion and blend ratio of the colored polyester filament and natural cotton staple fiber in yarn spinning process, a series of composite yarns were designed and prepared with various segmented structure and cyclical change of the distinct colors. The blend ratio was found to strongly influence on the segment frequency and yarn performance, achieving an improved mechanical property and yarn performance. A color systematic analysis indicated that the combination of alternating structural change induced interval color sense and gradient at the merged regions would lead to an enhanced stereoscopic visual effect of the composite yarns. Moreover, the composite yarns were confirmed to have an excellent weavability and able to endow different patterns and visual effects to the textiles. Thus, considering of the above advantages and multifunctionalities, this work should spur great possibilities for dyeing industry with the promising physical spinning method.

A novel composite cotton yarn with phase change and electrical conductivity functions

PAN/PEG/CNT/cotton composite yarn (PPCCY) was fabricated by impregnating PEG2000–10000 into CNT/cotton yarn (CCY) and coating electrospun PAN around its surface. The effects of PEG type on the morphology, structure, electrical resistance and phase change behavior of the produced composite yarns were studied thoroughly by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric(TG), electrical resistance tester and infrared thermal images. The experimental results indicated that the resulting compound yarn consisted of conductive yarn within which the spacing between cotton fibers was fulfilled by PEG, rendering phase transition enthalpy from 126–150 Jg−1. The composite yarn exhibited adjustable temperature and thermal storage and electrical conductivity abilities. The composite yarn demonstrated good responsive properties to external electrical and thermal stimuli and had reversible heat conversion and storage, which shows a promise for applications in electrical wearable fabrics.