Search

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova–Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH–urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova–Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340–474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

The environmental burden of the textile industry can be decreased with an increased use of mechanically recycled fibers. However, it is well known that the recycling process is harsh and shortens the fibers substantially. Still, little has been investigated about the influencing factors of the fiber length loss. Previous research has shown that the parts of a garment that is more worn, lose less fiber length in the mechanical recycling process.1 One explanation could be that a loss of fibers during wearing create a more open structure of the textile. By removing fibers from the yarns in a textile, the yarn structure is partly broken down, and the yarn linear density is decreased. The strength of spun staple fiber yarns is dependent on the friction and contact surfaces between fibers. In addition, fiber migration, the variation of radial position of a fiber in the yarn, causes the fibers to lock between different helical layers and thus creates a self-locking mechanism giving strength to the yarn.2 Removal of any fiber in such a yarn affect all fibers in contact with that fiber. This in turn makes both the textile and yarns weaker and consequently more easily disentangles in a mechanical recycling process – keeping more of the fiber length. The work at hand investigated this theory by subjecting woven cotton textiles with abrasion treatment prior to mechanical recycling. We compared two different methods of abrasion with unabraded textile. The two pre-treatment abrasion methods used were rubbing with sandpaper and raising with steel pins. By measuring the fiber length post mechanical recycling, we could estimate the efficiency of the recycling process in respect to preservation of the fiber. Results showed that only the raising process had a positive impact in mitigating fiber length loss through the recycling process. During the rubbing with sandpaper, the fabric was pressed and thus became denser. On the contrary, the raising process pulled out the fibers and cr

All-cellulose composites (ACCs) are manufactured using only cellulose as a raw material. Biobased materials are more sustainable alternatives to the petroleum-based composites that are used in many technical and life-science applications. In this study, an aquatic NaOH-urea solvent system was used to produce sustainable ACCs from wood-based woven textiles with and without the addition of TEMPO-oxidized nanocellulose (at 1 wt.-%). This study investigated the effects of dissolution time, temperature during hot press, and the addition of TEMPO-oxidized nanocellulose on the mechanical and thermal properties of the composites. The results showed a significant change in the tensile properties of the layered textile composite at dissolution times of 30 s and 1 min, while ACC elongation was the highest after 2 and 5 min. Changes in hot press temperature from 70 °C to 150 °C had a significant effect: with an increase in hot press temperature, the tensile strength increased and the elongation at break decreased. Incorporating TEMPO-oxidized nanocellulose into the interface of textile layers before partial dissolution improved tensile strength and, even more markedly, the elongation at break. According to thermal analyses, textile-based ACCs have a higher storage modulus (0.6 GPa) and thermal stabilization than ACCs with nanocellulose additives. This study highlights the important roles of process conditions and raw material characteristics on the structure and properties of ACCs.

This study reports the recycling of discarded denim textiles by the production of all-cellulose composites (ACCs). Discarded denim fabrics were shredded into fibers and then made into nonwoven fabrics by carding and needle punching. The produced nonwoven fabrics were converted to ACCs by one-step and two-step methods using an ionic liquid (IL), 1-butyl-3-methyl imidazolium acetate ([BMIM][Ac]). In this study, the effect of different ACC manufacturing methods, denim fabrics with different contents (a 100% cotton denim (CO) and a blend material (cotton, poly-ester and elastane (BCO)) and reusing of IL as a recycled cellulose solvent on the mechanical pro-perties of the formed ACCs were investigated. The ACCs were characterized according to their tensile and impact properties, as well as their void content. Microscopic analysis was carried out to study the morphology of a cross-section of the formed composites. The choice of the one-step method with recycled IL, pure IL or with a blend material (BCO) had no influence on the tensile properties. Instead, the result showed that the two-step method, with and without DMSO, will influence the E-modulus but not the tensile strength. Regarding the impact properties of the samples, the only factor likely to influence the impact energy was the one-step method with CO and BCO.

Funding: Vinnova, Collaboration between Swedish School of Textiles, AUTEX and University of Ghent

Although there has been some research on how to use short fibers from mechanically recycled textiles, little is known about how to preserve the length of recycled fibers, and thus maintain their properties. The aim of this study is to investigate whether a pre-treatment with lubricant could mitigate fiber length reduction from tearing. This could facilitate the spinning of a 100% recycled yarn. Additionally, this study set out to develop a new test method to assess the effect of lubricant loading. Inter-fiber cohesion was measured in a tensile tester on carded fiber webs. We used polyethylene glycol (PEG) 4000 aqueous solution as a lubricant to treat fibers and woven fabrics of cotton, polyester (PES), and cotton/polyester. Measurements of fiber length and percentage of unopened material showed the harshness and efficiency of the tearing process. Treatment with PEG 4000 decreased inter-fiber cohesion, reduced fiber length loss, and facilitated a more efficient tearing process, especially for PES. The study showed that treating fabric with PEG enabled rotor spinning of 100% recycled fibers. The inter-fiber cohesion test method suggested appropriate lubricant loadings, which were shown to mitigate tearing harshness and facilitate fabric disintegration in recycling.

Thermoplastic bio-composite have a higher potential of use based on the sustainability benefits. Natural fibres today are a popular choice for applications in biocomposite manufacturing. Hybrid yarns are a satisfactory solution to improve the fabrication of composites containing a thermoplastic matrix and plant-based fibres. Nevertheless, it is still difficult to produce bio-composites with superior mechanical properties, due to problematic impregnation and consolidation results during the production process. This paper investigates the processing parameters for the compression moulding of two different hemp/PLA textiles structure bio-composites (warp knitting and weaving structure). Finite element simulations are used to optimise the processing parameters (pressure, temperature, and time). The results demonstrated that the textile structure has a small effect on the time of production. Main while the pressure and temperature of processing parameters depend only on the type of matrix and the thickness of biocomposite has a big impact on the time of production.

This paper investigates the processing parameters for the compression molding of hemp/PLA hybrid yarn biocomposites and their effect on the final mechanical properties. Finite element simulations are used to develop and assess the processing parameters, pressure, temperature, and time. These parameters are then evaluated experimentally by producing the composites by two different methods, to compare the results of experimentally determined processing conditions to parameters determined by the simulation analysis. The assessment of mechanical properties is done with several experimental tests, showing small improvements for the composites produced with the simulation method. The application of the simulation analysis results in considerably reduced processing times, from the initial 10 min to only three minutes, thereby vastly improving the processing method. While the employed methods are not yet able to produce composites with greatly improved mechanical properties, this study can be seen as a constructive approach, which has the ability to lead to further improvements.

The aims of this paper is to demonstrate the effect of warp tension on fabric colour for several types of weaves structures, and found a relationship between them. The image analyse technique used to determine the proportion of yarns colour appearance, the advantage of this techniques is the rapidity and reliability. The woven fabric samples are consisting of a polyester warp yarn with continuous filaments and density of 33 end/cm, a polypropylene weft yarn with a density of 24 pick/cm, and the warp tension ranged between 12-22 cN/tex. The experimental results demonstrated the effect of the warp tension on the colour of fabric, and this effect is related to several factors, where the large proportion of warp appearance leads to larger effect on fabric colour. The difference in the value of colour differences ΔEcmc is larger is in the range 16 to 20 cN/tex of warp tension. Using statistical methods, a mathematical model to calculate the amount of the colour difference ΔEcmc caused by the change in warp tension had been proposed.