The hydration of TENCEL ® cellulose fibres studied using contrast variation in small angle neutron scattering

Investigate the fabric performance of Tencel-cotton blended denim in terms of the percentage change of Tencel

In terms of sustainability & wearing comfort, denim manufacturers are entering a new era of product variety. Tencel's regenerative nature and unique mechanical qualities usher in a new era for the denim industry. In this work, denim fabrics were manufactured using Tencel Cotton blended yarn using very fi ne yarn (20 Tex or 30 Ne), and fabric performance was examined following factors like tensile strength and other relevant metrics. For better evaluation, All the structures were 2/1 RHT (right-hand twill) that contained 115 EPI & 70 PPI and also indigo blue dyed. According to the result of the investigation, 100% Tencel Fabric (both the warp and the weft yarn were 100% Tencel) demonstrated the highest quality of fabric performance in terms of tensile strength, tearing strength, stiff ness, air permeability, and water vapor permeability than any other cotton or cotton Tencel blended fabric. However, a downward trend of abrasion resistance was observed in Tencel or cotton Tencel blended fabric concerning the percentage change of Tencel. Additionally, the performance of the fabric was significantly improved by the percentage addition of Tencel fiber in the warp and weft directions. In addition, a denim fabric made entirely of cotton performed the least well when compared to fabrics made entirely of Tencel or a blend of Tencel and cotton.

Quantitative Evaluation of the Hierarchical Porosity in Polyimide Aerogels and Corresponding Solvated Gels

Aerogels are promising materials for many aerospace applications, including high-performance antennae and flexible insulation, because of their inherent low density and high surface areas. Polymer aerogels, especially polyimide aerogels, provide excellent mechanical properties beyond traditional silica aerogels while maintaining the required thermal stability. Polyimide aerogel surface area, porosity, and pore volume are important properties; however, these measurements are traditionally conducted on the aerogel after removal of the solvent. Because of this, the impact of synthetic control and solvent presence on the nanoscale to mesoscale structure of polyimide aerogels in functional applications is unclear. In this report, we use small-angle neutron scattering to determine the dry and solvated skeletal strut size and composition of polyimide aerogels to deduce the impact of solvation on the structure of complex aerogel struts. Our results show that the aerogel contains a hierarchical assembly of pores, with pores present both within and between the supporting struts. This translates to a material with solvent in the larger pores, as well as absorbed in the supporting polyimide skeleton. The amount of solvent uptake in the struts varies with the solvent and polyimide properties. The insight from these results provides pathways to determine the correlations between aerogel nano- and mesoscale structural characteristics, fabrication processes, and their performance in functional applications such as polymeric battery separators. These results also broaden the characterization tools of polymeric aerogels that differentiate between dry and solvated nano- and mesoscale structures that exist in common operating conditions.

Liquid infiltration into carbon nanotube fibers: effect on structure and electrical properties

Carbon nanotube (CNT) fibers consist of a network of highly oriented carbon nanotube bundles. This paper explores the ingress of liquids into the contiguous internal pores between the bundles using measurements of contact angles and changes in fiber dimensions. The resultant effects on the internal structure of the fiber have been examined by WAXS and SAXS. A series of time-resolved experiments measured the influence of the structural changes on the electrical resistivity of the fiber. All organic liquids tested rapidly wicked into the fiber to fill its internal void structure. The local regions in which the nanotube bundles are aggregated to give a bundle network were broken up by the liquid ingress. For the range of organic penetrants examined, the strength of the effects on structure and electrical resistivity was correlated, not only with the degree to which the liquid reduced the nanotube surface energy, but also with the Hansen affinity parameters. The fact that liquid environments influence the electrical performance of these fibers is of significance if they are to replace copper as power and signal conductors, with added implications regarding the possible ingress of external insulating materials, and possibly also sensing applications.

Nanostructure of cellulose microfibrils in spruce wood

The structure of cellulose microfibrils in wood is not known in detail, despite the abundance of cellulose in woody biomass and its importance for biology, energy, and engineering. The structure of the microfibrils of spruce wood cellulose was investigated using a range of spectroscopic methods coupled to small-angle neutron and wide-angle X-ray scattering. The scattering data were consistent with 24-chain microfibrils and favored a "rectangular" model with both hydrophobic and hydrophilic surfaces exposed. Disorder in chain packing and hydrogen bonding was shown to increase outwards from the microfibril center. The extent of disorder blurred the distinction between the I alpha and I beta allomorphs. Chains at the surface were distinct in conformation, with high levels of conformational disorder at C-6, less intramolecular hydrogen bonding and more outward-directed hydrogen bonding. Axial disorder could be explained in terms of twisting of the microfibrils, with implications for their biosynthesis.

Enzymatic Treatments on Tencel in Water and Microemulsion

Tencel is a relatively new fabric, obtained from wood pulp, that looks like natural cotton. In order to be suitable for commercial purposes, Tencel must be processed to improve its qualities. In this paper we report our studies on the enzymatic defibrillation of Tencel, in which we checked the different behavior of the same set of enzymes dispersed in pure water and in a microemulsion system. Surface properties, such as scanning electron microscopy, contact angle, porosimetry, breaking load, and thickness, were determined, in order to monitor the surface modification of the fabric upon enzymatic defibrillation, and indicate that the process is more efficient and less damaging when carried out in the microemulsion medium. Furthermore, we chemically modified Tencel by attaching fluorinated chains to the fabric surface. Surface properties show that fluorination of Tencel leads to a high degree of water- and oil-repellency in the fabric. Copyright 2001 Academic Press.