Fibrous microplastics (FMPs) are ubiquitous worldwide, existing from lands to oceans and from surface waters to sediments. Ingestion and toxic effects of FMPs have been detected in organisms. FMPs released from synthetic textiles during laundering are thought to be a large source contributing to the current overall load of microplastics (MPs) in the environment. Given the fast growth of the synthetic textile market and the continuing emission of FMPs, this review aims to present measures to reduce FMP emissions to the environment. To achieve this aim, we summarise existing data and knowledge about FMPs to elucidate (a) the definition of FMPs, (b) FMP release during textile washing and influencing factors, and (c) FMP retention in wastewater treatment plants (WWTPs) at different treatment stages and subsequent emission to the aquatic environment. Based on the existing data, we estimate that the annual release of FMPs from synthetic textile washing is in the range of 50.6–1180 kg per 100 000 population. Such release might lead to an overall emission of 2.53–59 kg FMPs per year via WWTP discharges (serving 100 000 residents) to the receiving waters assuming a 95% WWTP removal efficiency. To this end, proactive solutions and suggestions are studied to avoid and reduce the release and emission of FMPs, considering reduction, reuse, recycling and end-of-pipe strategies.

Chitosan is a natural biopolymer that can be suitable for a wide range of applications due to its biocompatibility, rigid structure, and biodegradability. Moreover, it has been proven to have an antibacterial effect against several bacteria strains by incorporating the advantages of the electrospinning technique, with which tailored nanofibrous scaffolds can be produced. A literature search is conducted in this review regarding the antibacterial effectiveness of chitosan-based nanofibers in the filtration, biomedicine, and food protection industries. The results are promising in terms of research into sustainable materials. This review focuses on the electrospinning of chitosan for antibacterial applications and shows current trends in this field. In addition, various aspects such as the parameters affecting the antibacterial properties of chitosan are presented, and the application areas of electrospun chitosan nanofibers in the fields of air and water filtration, food storage, wound treatment, and tissue engineering are discussed in more detail.

Textiles are used for many different applications and require a variety of properties. Wet functionalization improve textiles’ properties, such as hydrophilicity or antimicrobial activity. Chitosan is a bio-based polymer widely investigated in the textile industry for this purpose. A weaving comprising a cotton/polyester mix and a pure-polyester weaving was functionalized with different concentrations of chitosan to determine the most robust method for chitosan detection in both cotton- and polyester-containing materials. Additionally, mixtures of chitosan with 3-glycidyloxypropyltriethoxy silane (GLYEO) or 3-aminopropyltriethoxy silane (AMEO) were applied in a one-step or two-step procedure on the same fabrics. Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) and dyeing with Remazol Brilliant Red F3B demonstrated the presence of chitosan and silanes on the textiles’ surfaces. While non-functionalized textiles were not stained, the dependency of the dyeing depths on the chitosan concentrations enabled us to infer the efficacy of the very short processing time and a mild dyeing temperature. The one-step application of AMEO and chitosan resulted in the highest presence of silicon on the textile and the greatest color intensity. The functionalization with GLYEO reduced the water sink-in time of polyester, while chitosan-containing solutions increased the hydrophobicity of the material. Washing experiments demonstrated the increasing hydrophilicity of the cotton/polyester samples, independent of the type of functionalization. These experiments show that chitosan-containing recipes can be used as part of a useful method, and the type of functionalization can be used to adjust the hydrophilic properties of polyester and cotton/polyester textiles. Via this first step, in the future, new combinations of bio-based polymers with inorganic binder systems can be developed, ultimately leading to sustainable antimicrobial materials with modified hydrophilic properties.

Sunlight is essential for humans. However, sunlight can be the source of several disadvantageous effects and illnesses, e.g., skin aging, sunburn, and skin cancer. Textiles with functional protective effects can counteract these problems. In the current research, knitted fabrics were produced from Lyocell yarns spin-doped with the inorganic UV absorber titanium dioxide TiO₂. Lyocell yarns without TiO₂ were used as reference materials. The produced knitted fabrics were dyed with different dyestuffs to improve the protective properties against UV light and infrared light. The protective properties are determined by optical spectroscopy in an arrangement of diffusive transmission. With the two dyestuffs Drimaren Yellow HF-CD and Solophenyl Bordeaux 3BLE, dyes were determined which complete UV protection and additionally reduce transmission in the near-IR range (700 nm to 1000 nm). TiO₂ in the fibers enhanced this effect. In the UV range (280 nm to 400 nm), the transmission was almost zero with both dyes. Overall, the Lyocell samples containing TiO₂ exhibit less sensitivity to abrasion and a UV protective effect after washing can be still determined. The weight loss after the abrasion test for these samples is quite low with only around 8.5 wt-% (10,000 rubbing cycles in the Martindale device). It is concluded that the right choice of dye can improve the protective effect of textiles against various types of radiation. Lyocell fiber-based textiles are suitable for the production of summer clothing due to their good moisture management. Compared to other radiation protective materials based on coating application, the presented solution is advantageous, because the textile properties of the realized products are still present. For this, a direct transfer to clothing application and use in apparel is easily possible. This study can be seen as the first proof-of-concept for the future development of light-protective clothing products.

Smart textiles have properties that outperform the conventional protective and decorative function of textiles. By integrating special sensors into clothing, body functions and movements can be detected. Piezoresistive sensors measure a change in electrical resistance due to the application of force in the form of stretching, pressure or bending. In order to manufacture such sensors, conventional non-conductive textile materials need to be made conductive by finishing processes. Therefore, a non-conductive silicone monofilament was coated with a conductive carbon silicone and additional silver-containing components and investigated for its suitability as a strain sensor. The changes in electrical resistance and the gauge factor as a measure of the sensitivity of a sensor were measured and calculated. In this publication, the electrical properties of such a filament-based sensor in the context of particle composition and concentration are discussed. The electrical resistance was already significantly reduced in a first step by coating with conductive carbon silicone (145 kΩ). The addition of silver-containing components further reduced the electrical resistance in a second step. Thereby, flat flakes of silver proved to be much more effective than silver-containing particles (5 kΩ at 20% addition). The former was easier to integrate into the coating and formed contact surfaces with each other at higher concentrations. Stretching the samples increased the resistance by enlarging the distance between the conductive components. With 30% silver-coated glass flakes in the coating, the highest gauge factor of 0.33 was achieved. Consequently, the changes in electrical resistance during stretching can be exploited to detect motion and the gauge factor indicates that even small changes in strain can be detected, so the herein developed coated monofilaments are suggested for use as strain sensors. Future work includes matching the particle composition and concentration to the exact application and investigating the sensors in the field.

Polyester is the leading man-made fiber in the field of textiles and clothing. Polyester is usually dyed and finished using a process temperature in the range of 120 to 135 ºC. Such a process is known as a high-temperature (HT) process. The application of chitosan on cellulosic materials is an interesting approach to textile functionalization. In contrast, the application of chitosan by the HT process for the functional treatment of polyester is less investigated. With this background, the present study is related to the surface characteristics of different polyester fabrics with implemented chitosan after performing the HT process.