Pineapple leaves can provide competitive and high-quality fibers for textile purposes. Despite pineapple being cultivated in the Portugues islands there is still a technology gap for the extraction and treatment of Pineapple Leaf Fibers (PALF) in Europe. Since Azorean Pineapple differs significantly from other plants in the bromeliad family, the properties and characterization of its leaf fibers were explored for the first time. Long fibers have been extracted by hand scraping and compared to biological retting at 25 °C for different time periods. It was explored the properties of PALF from plants of different ages (11- and 18-months) and from different zones of the leaves (beginning, middle, and tip). Physical-mechanical properties of Azores PALF were determined, including diameter, linear density, strength, Young's modulus, and elongation at break and characterized by ATR-FTIR, XRD, TGA/DTG, and FESEM to understand their chemical and morphological characteristics. While slight differences were observed between different ages, variations in physical-mechanical properties were notable among fibers extracted from different leaf positions. Extraction of Azores PALF through 25 °C biological retting for 14 days effectively eliminated non-fibrous matter and produced the thinnest and strongest fibers. These fibers ranged between 34.9 and 168.3 μm in diameter, 1.39 and 7.07 tex in linear mass density, 37–993 MPa in tensile strength, 1.0–3.9 % in elongation at break, and 2.4–21.8 GPa in Young's modulus.

In this work, we report a selective and straightforward process to synthesize glycerol carbonate from urea and glycerol using a simple but commercially unavailable catalyst (Sn(OH)₂).

The textile industry is under increasing pressure to adopt sustainable practices due to the significant environmental impacts associated with fiber production, including high energy consumption, water usage, and substantial greenhouse gas emissions. The recycling of textile waste, particularly cotton, is a promising solution that has the potential to reduce landfill waste and decrease the demand for virgin fibers. However, mechanically recycled cotton fibers frequently demonstrate diminished mechanical properties compared to virgin fibers, which limits their potential for high-quality textile applications. This study explores the use of cross-linking agents (citric acid (CA) and sodium hypophosphite (SHP)), polymers (polyethylene glycol (PEG), chitosan (CH), carboxymethyl cellulose (CMC) and starch (ST)), and silicas (anionic (SA) and cationic (SC)) to enhance the mechanical properties of recycled cotton fibers. The treatments were then subjected to a hierarchical ranking, with the effectiveness of each treatment determined by its impact on enhancing fiber tenacity. The findings of this research indicate that the most effective treatment was starck (ST_50), which resulted in an enhancement of tenacity from 14.63 cN/tex to 15.34 cN/tex (+4.9%), closely followed by CA-SHP_110/110, which also reached 15.34 cN/tex (+4.6%). Other notable improvements were observed with CMC_50 (15.23 cN/tex), PEG_50 (14.91 cN/tex), and CA_50 (14.89 cN/tex), all in comparison to the control. In terms of yarn quality, the CA-SHP_110/110 treatment yielded the most substantial reductions in yarn irregularities, including thin places, thick places, and neps with decreases of 36%, 10%, and 7%, respectively. Furthermore, CA_50 exhibited moderate enhancements in yarn regularity, thin places (−12%), thick places (−6.1%), and neps (−8.9%). The results of this study demonstrate that combining CA with SHP, particularly when preceded by the heating of the solution before the addition of the fibers, results in a substantial enhancement of the structural integrity, strength, and overall quality of recycled cotton fibers. This approach offers a viable pathway for the improvement of the performance of recycled cotton, thereby facilitating its wider utilization in high-quality textile products.

Selective removal of elastane from textile blends is a critical factor for fibre-to-fibre recycling, since even low elastane content compromises the mechanical shredding efficiency, contaminates recycled streams, and limits the spinnability of recovered fibres. In this work, we investigate dimethyl sulfoxide (DMSO) as a solvent system for elastane degradation under moderate temperatures, both in the absence and in the presence of the organic base catalyst 1,5-diazabicyclo[4.3.0]non-5-ene (DBN). DMSO alone promoted only partial elastane mass loss, typically 26–32% at 80–100 °C (60 min) and up to 79% at 120 °C (10 min), whereas the addition of 0.1% v/v DBN enabled near-complete or complete mass loss (81–100%) across 80–120 °C within 10–60 min. Complete removal of elastane was achieved in isolated elastane filaments at 100 °C within 30–60 min, and the same treatment conditions were applied to real mixtures of pre-consumer textile waste containing 94% cotton/6% elastane and 87% polyester/13% elastane, leading to permanent dimensional relaxation of the resulting fabrics with area increases of approximately 9–14% and 7–13%, respectively, consistent with the loss of elastane-driven elastic recovery. Scanning electron microscopy (SEM), tensile testing, and dimensional analysis confirmed selective disruption of the elastane, a loss of elastic recovery, and largely preserved morphology and tensile strength of the cotton and polyester fibres. Dimensional change in the treated fabrics served as an indirect indicator of elastane degradation, correlating with the loss of elasticity observed in both blends. In summary, the DMSO–DBN system provides an energy-efficient, controllable, and scalable route for elastane degradation under comparatively mild conditions, thereby contributing to fibre-to-fibre recycling strategies and the advancement of circular textile manufacturing.

Glycerol is an unavoidable by-product of the biodiesel production process. The conversion of glycerol into valuable biofuel additives is essential in the fuel industry. The goal of this work is to develop a reactive distillation-based process for the production of biofuel additives by bio-glycerol etherification. In this study, a kinetic model using a lumping approach for glycerol etherification with tert-butyl alcohol (TBA) over Sn (II) phosphomolybdate (Sn_1.5PMo₁₂O₄₀) catalyst was developed. Aspen Plus was used to validate the kinetic model by simulating the glycerol etherification with TBA in a batch reactor. The model predictions were in good agreement with the experimental data. A reactive distillation-based process to produce glycerol ethers was developed, and heat integration was conducted to reduce energy consumption. The energy requirements of the integrated process and the CO₂ emissions were decreased by 17% and 14%, respectively. An economic evaluation was performed to study the profitability of the process for an annual capacity of 33,000 metric tons of glycerol ethers. It was found that the process is economically attractive, with a return on investment of 29.40% and a payback period of 2.2 years. The reactive distillation-based process is green and promising for producing biofuel additives that are sustainable and environmentally friendly.