Several qualities influence the processability of textile staple fibers: inter-fiber cohesion being one of the most important properties. Although various methods to measure this property have been explored, there is no consensus on the optimal technique, and existing methods often require specialized machinery. This article introduces and evaluates a straightforward method that utilizes only a carding machine and a tensile tester, both standard equipment in yarn laboratories. The proposed cohesion test method involves preparing carded webs, cutting them into nine rectangles, and then subjecting these samples to tensile testing. The method was initially assessed for repeatability and the normalization of results. Further experiments varied the fiber material (cotton and polyester), fiber organization, direction of fiber hooks, and finishing treatments. Force curves and their gradients were analyzed, alongside video footage, to study inter-fiber interactions during testing. The results demonstrated that the new test method could differentiate between fiber materials, fiber organizations, and quantify the effects from finishing treatments. The cohesion force (CF) of CO fibers was 30 % of that of PES fibers; carding had a greater impact on CO fibers compared to PES fibers, and treatment with lubricant reduced the CF by up to 35 %. However, the weight and dimensions of the samples must be controlled to ensure repeatability. In conclusion, the developed inter-fiber cohesion test method offers a promising and accessible approach to analyzing inter-fiber interactions in staple fibers.

Rendering any surface non-wettable requires it to be clean and dry after the droplet is deposited or impacted. Leveraging and quantifying the non-periodic or random topology non-wettable is intricate as the Cassie-Baxter state competes with the Wenzel or impaled state, which becomes further challenging for irregular and heterogeneous nonwoven materials. Herein, we report the fundamental insights of the impalement dynamics of droplets on metastable nonwovens and self-similar nonwoven-titanate nanostructured materials (SS-Ti-NMs) using laser scanning confocal microscopy in three dimensions. Our results represent the first example of liquid imbibition in metastable nonwovens and SS-Ti-NMs involving a complex interplay between a triumvirate of factors – the number of fibres in the defined cross-sectional area (volume), pore features, and intrinsic wetting properties of the constituent entities. Predictive models of the apparent contact angle and breakthrough pressure for nonwovens and their SS-Ti-NMs have been proposed based on micro- and nano-scale structural parameters. Enabled by X-ray microcomputed tomography analysis, a key set of three-dimensional fibre and structural parameters of nonwovens has been unveiled, which played a vital role in validating the predictive models of apparent contact angles.

In this study, lignin underwent chemical modification via acetylation of hydroxyl groups to enhance its interfacial connection with poly (lactic acid) (PLA). Further enhancement of the blend was attained by adding an impact modifier, Biomax Strong. Incorporating Biomax Strong into PLA-lignin blends resulted in improvements in material characteristics, particularly in impact strength and thermal stability. This blend exhibited a unique set of mechanical properties, characterized by a reduction in tensile modulus as well as an increase in ductility. This will allow a more versatile use of PLA in various applications. The observed improved impact strength highlights the synergistic effect of stress redistribution within the PLA matrix contributing to widespread applications of PLA based composites. This can clearly be observed for the compound containing PLA and 15 wt.% lignin, where the impact strength was approximately 15 kJ/m2. With the addition of 5 wt.% impact modifier, the impact strength increased by 60 %, reaching approximately 25 kJ/m2. This synergy effect reinforces the overall structure, improving the impact toughness behavior. The combination of Biomax Strong and lignin not only address the limitations of PLA but also introduces new opportunities for applications requiring a balance of impact strength, ductility, and thermal stability. These advancements indicate a promising future for composite materials in various applications.

The mechanical textile recycling process significantly reduces fibre length. Previously, we explored how lubricant pre-treatment before mechanical recycling reduced the fibre length loss. In this study, we added simulated wear to assess its influence on the fibre length output. We also evaluated the influence of sample shape and feed direction on recycling efficiency. We treated plain woven cotton textiles were subjected to either sandpaper grinding or steel needle raising. Finishing treatments with polyethylene glycol 4000 and Afilan CFA 100 were also used in combination. Samples were prepared in two shapes and fed into the recycling machine with warp threads oriented longitudinally, perpendicularly, or diagonally. Recycling efficiency was evaluated based on fibre length and the degree of fibre opening using a novel air flow permeability test. The results showed that sandpaper treatment degraded fibres, while the raising treatment improved recycling efficiency. A previously unreported finding was that the size, shape and feeding direction of woven fabrics showed significant effects on the fibre length output. Material fed with a thread system aligned longitudinally to the recycling machine direction resulted in a higher proportion of opened fibres and fewer unopened fabric pieces. It was further observed that the yarns aligned longitudinally with the feed direction exhibited significant opening, while those oriented perpendicularly remained largely unopened. The new method for measuring the degree of opened fibres proved effective and holds promise for future application. These findings provide tangible guidance on the mechanical recycling protocol and means to improve output assessment procedures.

All-cellulose composites (ACCs) have been fabricated by using a variety of cellulosic sources, versatile technologies, and are sustainable alternatives for traditional composites. In this study, nonwoven-woven ACC laminates were created from wood-based Spinnova short fibers and Lyocell fabrics via partial dissolution and an NaOH-urea solvent system. The less-known wood-based Spinnova fiber is created for the textile industry, but it also has great potential for the composite industry. To identify the mechanical properties of ACCs—which greatly influence the range of material application—tensile, impact, and flexural tests were conducted. The mechanical properties indicated only moderate properties, which are influenced by high porosity and weak fiber bonding. Despite this, valuable information on the nonwoven-woven structured ACCs was obtained. To improve the ACC laminate’s ability to resist moisture, bio-based coatings (e.g., commercially available birch bark betulin and suberin acid mixture) were applied on the surface of ACCs and it successfully improved the wetting resistance. The results of contact angle analyses demonstrated that the highest contact angle of 128° was measured for betulin-coated laminates and the best stable hydrophobicity calculated a minute after the beginning of the experiment were observed at 109° for the uncommercial pressurized hot ethanol (PHE) extract of birch bark.

The aim of this study is to investigate the feasibility of an alternative Fenton-based advanced oxidation process for the discoloration of reactive-dyed waste cotton as a pre-treatment for textile recycling. For that, pre-wetted dark-colored (black and blue) knitted samples of 300 cm2 are treated in 1200mL Fenton-solution containing 14 mM Fe2+ and 280mM H2O2 at 40 °C. Characterization of the textiles before and after the treatments are performed by UV VIS-spectrophotometry measuring color strength, microscopy, FTIR spectroscopy, thermal analysis and tensile testing measuring tenacity and elongation. Afterwards, the cotton is mechanically shredded for qualitative analysis of the recyclability. The color-strength measurements of the black and blue cotton led to discoloration-efficiencies of respectively 61.5 and 72.9%. Microscopic analysis of discolored textile fabric also showed significant fading of the colored textiles. Mechanical analysis resulted in reduced tensile strength after treatment, indicating oxidation of the cellulosic structure besides the degradation of the dye-molecules, also confirmed by reductions in thermal stability found after thermal analysis. Shredding of the fabric resulted in enhanced opening, but shorter remaining fibers after treatment. The findings of this study provide a proof-of-concept for an alternative color-stripping treatment concerning a Fenton-based advanced oxidation process as a pre-treatment for textile recycling.

Textile production has doubled in the last 20 years, but only 1% is recycled into new fibers. It is the third largest contributor to water pollution and land use, accounting for 10% of global carbon emissions and 20% of clean water pollution. A key challenge in textile recycling is blended yarns, such as polycotton blends, which consist of polyester and cotton. Chemical recycling offers a solution, in particular, alkali treatment, which hydrolyzes polyester (PET) into its components while preserving cotton fibers. However, conventional methods require high temperatures, long durations, or catalysts. Our study presents, for the first time, the heated high-ethanol alkaline aqueous (HHeAA) process that efficiently hydrolyzes PET from polycotton at lower temperatures and without a catalyst. A near-complete PET hydrolysis was achieved in 20 min at 90 °C, while similar results were obtained at 70 °C and 80 °C with longer reaction times. The process was successfully scaled at 90 °C for 20 min, and complete PET hydrolysis was achieved, with a significantly reduced liquid-to-solid ratio, from 40 to 7 (L per kg), signifying its potential to be implemented in an industrial context. Additionally, the cotton maintained most of its properties after the treatment. This method provides a more sustainable and efficient approach to polycotton recycling.

Autohesion is a unique class of adhesion that enables the bonding of two identical surfaces by establishing intimate contact at interfaces. Creating intimacy between two identical surfaces poses a challenging task, often constrained by the presence of surface roughness and chemical heterogeneity. To surmount this challenge, we document a variety of autohesive traits in polypropylene-based meltblown nonwovens, accomplished through a facile, scalable, energy-efficient, and cost-effective ultrasonic bonding process. The mean work of autohesion for a single polypropylene bond, serving as a figure of merit, has been computed by extending the classical Johnson−Kendall−Roberts (JKR) theory by factoring in peel strength along with key fiber and structural parameters of nonwoven materials. Achieving a high figure of merit in ultrasonically bonded nonwovens hinges on the synergistic interplay of key process parameters, including static force, power, and welding speed, with the fiber and structural properties acting in concert. In this regard, peel-off force analysis has also been conducted on a series of twenty-seven ultrasonically bonded meltblown nonwovens prepared using a 33 full factorial design by systematically varying process parameters (static force, power, and welding speed) across three levels and extension rate. X-ray microcomputed tomography (microCT) analysis has been performed on select ultrasonically bonded nonwoven samples to discern their bulk characteristics. A broad spectrum of mean work of autohesion for a single polypropylene bond, ranging from 1.88 to 9.93 J/m², has been ascertained by modulating key process parameters.

Bioplastics that possess characteristics like durability and low cost are desired for versatile applications in industries such as automotive manufacturing, marine transport manufacturing, aerospace applications, and the building industry. The automotive industry is an example of an industry that is now shifting towards a more focused approach addressing the issue concerning sustainability and the development of sustainable material. To achieve a lightweight and sustainable construction, one of the methods used by the automotive original equipment manufacturers is by substituting conventional fossil-based, non-renewable composites, and metallic materials with a bio-based alternative. One of the drawbacks with biobased polymers can be the poor interfacial adhesion, leading to poor mechanical properties when compares to conventional material. The aim of this research is to investigate if a low-cost by-product could be used as a component in a composite matrix material in the automotive industry to reduce the final weight and increase the non-petrochemical material usage of composite material without compromising the thermal and mechanicals properties demanded. In this research, lignin was chemically altered by esterification the functional groups to increase the compatibility with polylactic acid. The esterification was performed with the use of acetic acid anhydride and pyridine. To evaluate and determine the esterification, Fourier transform Infrared Spectroscopy was used. By blending the modified lignin with polylactic acid the intention was to improve the thermomechanical properties and the interfacial linkage between the components. The effects of lignin acetylation on the tensile properties, impact strength, and thermal stability and moisture repellence behaviour were investigated. According to the experimental results the modification of lignin, increased the impact strength for all the blends containing acetylated lignin compares to pristine lignin. The largest increase observed was for blends containing 20 wt% acetylated lignin and polylactic acid, which resulted in a 74% improvement compared with the blend composed of pristine lignin and polylactic acid. Similarly, the thermal stability was improved significantly with acetylation of the lignin. Moreover, the moisture repellence behaviour was also increased. The reason for the improved properties can be explained by the better interfacial compatibility between lignin and polylactic acid matrix. An increased thermal stability and a moisture repellent behaviour of the blends containing chemically modified lignin could be observed when compared with neat polylactic acid which makes the acetylation treatment of lignin a possible approach for the future of biocomposite production. 

Textile industry is witnessing the renaissance of hemp fiber, due to its sustainability. FINOLA is a breed of hemp that is grown in cold climates for grain production, including EU countries. 

However, after harvest, the residual stalks of these plants are considered low-value waste by-products. In this paper, we aim at optimizing the best methodology to extracting the short fibers from these agri-waste residue of FINOLA hemp, and to use them to produce higher-value technical textiles that can be used in many industries, such as construction and automotive, as an alternative to fossil-based fibers. Ultra-sound assisted mechanical extraction, with a multiple-step process had been developed for this residue. The obtained fibers are analyzed, and the relation between the process parameters and the fiber length is being investigated. The storage conditions will be assessed in relation with the obtained fiber length as well. This process is foreseen to increase the efficiency of this agricultural resource and contribute to circular economy and sustainability of textile sector.