Functional textiles - from research and development to innovations and industrial uptake

Resume : Context. The use of chemical warfare agents (CWA) on the battlefield and in civilian incidents increasingly threatens both military and civilian intervention teams. As these agents can be deadly upon single exposure, there is an urgent need for efficient protection of humans and equipments, particularly for the first responders after an attack and for decontamination teams. In contrast to generally used passive protection techniques – such as barriers, selective membranes and filters – which can lead to residual surface contamination with accumulation of CWA or biological agents on the outside of the protection system, photocatalytic layers can degrade CWAs and biological agents under UVA or solar light, directly on the clothing surface. Consequently, they do not require post-use decontamination to remove the toxics and the biological agents from the surface, such operations generally requiring strongly oxidizing or acid chemicals, so that waste treatment are also further needed. The degradation of the contaminants is also seen as an active protection that minimizes risks of cross-contamination and self-contamination during undressing. Here we present catalytically active functionalized textiles that provide active protection from CWAs and biological agents – without requiring the need of hazardous chemicals –, by depositing a TiO2-based photocatalytic top layer through a layer-by-layer technique (LbL). Photocatalysis on TiO2 has been shown to be a promising oxidation techni

Resume : Cotton materials, in the case of fire, represent a major risk, since it is flammable and burns strongly and fast. Commercial flame retardants, developed in 1950-1980, significantly improve flame retardancy, but are highly toxic. For that reason, novel flame retardants are researched. Silica compounds have good thermal properties by giving residue after the combustion process. Therefore, in this paper silica precursors were investigated in order to reduce the current high quantities of flame retardants and to reach the full protection. Two silica precursors have been applied by sol-gel treatments on cotton fabrics and compared to conventional flame retardants applied by the pad-dry-cure process. Conventional flame retardant urea and ammonium hydrogen phosphate (Ap3) was applied in full (urea 240g/l and ammonium hydrogen phosphate 115 g/l) and half (urea 120g/l and ammonium hydrogen phosphate 57,5 g/l) concentration. Silica precursors Tetramethoxysilane (TMOS) and Tetraethoxysilane (TEOS) were applied in concentration of 15 ml/l. Additionally, silica precursor TMOS and TEOS were added to conventional flame retardant. The flame retardancy and burning behaviour were determinated according to standard methods – ISO 15025:2000 Textile fabrics – Burning behaviour – Determination of ease of ignition of vertically oriented specimens, and ISO 4589:1996 – Plastics – Determination of burning behaviour by oxygen index in Limiting Oxygen Index (LOI) Chamber (Dynisco). For better understanding the changes in cotton structure under the heat conditions thermogravimetric method (TGA) on Pyris1 (PerkinElmer) and micro combustion calorimeter (MCC) MCC-2, Govmark, USA were used. For the durability burning behaviour was tested after 1 washing cycle according to ISO 6330:2012 Textiles - Domestic washing and drying procedures for textile testing The mixture of silica precursors with urea and ammonium hydrogen phosphate resulted in higher flame retardancy even when half the concentration of conventional FR was applied. It can be concluded that the silica phase formed by sol-gel process plays a protective role to degradation of the cotton fibers and it is able to modify the thermal and combustion behaviour of cellulose. The best results were achieved with the mixture of flame retardants - silica precursor TEOS, urea and ammonium hydrogen phosphate.

Resume : In this study commercial deep bed filter in form of polypropylene nonwoven was modified with in-situ grown iron oxide nanowires. Modification was realized in inexpensive and environmentally friendly route by hydrothermal method using aqueous solutions of iron(III) chloride - source of iron and urea - pH regulating agent which hydrolyzes at elevated temperature leading to the formation of hydroxide ions. Scanning electron macroscopic (SEM) observations showed that the iron oxide nanowires are homogeneously distributed on the outer surface of PP fibres creating dense structure composed of 50 nm wide and 170 nm long particles. Thermogravimetric analyses (TGA) revealed that the content of the iron oxide in this composite is c.a. 5 wt.%. The efficiency in arsenic removal from natural water (Wallis, Switzerland) was assessed using Inductively Coupled Plasma Mass Spectrometry (ICP MS). Results show that contact time needed to decrease As concentration to permissible level (0.01 mg/L) is less than 0.5 hour while 90% is removed after 2 hours. Acknowledgment This work was supported by a grant from Switzerland through the Swiss Contribution to the enlarged European Union. Author Justyna Tomaszewska is a beneficiary of the project ?Scholarships for PhD students of Podlaskie Voivodeship?. The project is co-financed by European Social Fund, Polish Government and Podlaskie Voivodeship.

Resume : Keratin extracted from wool has many useful properties, such as biocompatibility and biodegradability, and it supports the growth and the adhesion of fibroblasts and osteoblasts. Hydroxyapatite (HA) is used in bone reconstruction although it could not serve alone as bone repair device because of its weakness in strength. Electrospinning process is a method to produce nanofibrous materials endowed with peculiar properties that make them promising candidates for several applications, such as cell-growth, wound dressing and drug delivery. Keratin has been electrospun into nanofibres from solutions of formic acid; however, since HA particles are not stable in acid media, in order to functionalize keratin nanofibres with HA, water must be used as solvent. In this work, we carried out electrospinning tests with different keratin/HA water solutions and keratin/PEO/HA blends suitable for the production of composite nanofibrous scaffolds for bone tissue engineering applications. Electrospun keratin/PEO/HA nanofibers were subjected to heating treatments in an oven at different temperatures and times in order to assess heating temperature and time that confer to keratin nanofibers the required water stability. The samples, before and after the heating treatments, were put in deionized water for 24 h in order to study their behavior in water. All samples were characterized by SEM, EDX and FT-IR and the best electrospun mats were tested for osteoblasts cells growth.

Resume : The addition of inorganic colloids to polymer solutions allows the production of multi-component nanofibres by electrospinning. This process has been recently named “colloid electrospinning”. In this work, composite nanofibres were produced by electrospinning water solutions of keratin (protein extracted from wool) containing colloids of Ag or TiO2 (by Colorobbia, Italy). A renewable natural polymer (keratin) is used in a process involving water instead of organic solvents and liquid dispersions instead of nano-powder. Colloidal stability in polymer solutions was evaluated to preserve nanoparticle dimension before electrospinning. The resulting nanofibres were made water insoluble by a simple heat treatments at 180°C in air. Porous nanofibrous structure resulted stable to water. Finally, the functional properties of the nanofibres were evaluated. Antibacterial tests (AATCC 100) against Escherichia coli on nanofibres with Ag and TiO2 were carried out. Photo-catalytic tests were performed in water under a 9 W/m2 UV light using Rhodamine B as a model molecule. Degradation was measured by color changes using a spectrophotometer. Nanoparticle-loaded nanofibres showed bacterial reductions of 95% for Ag and 97% for TiO2. Photo-catalytic degradation of Rhodamine B was 53% for TiO2-loaded nanofibres after 2 h under UV light, while nanofibres without TiO2 reached 12% of conversion. The results demonstrated that nanoparticle functionalities were preserved in keratin nanofibres.

Resume : Cotton materials, in the case of fire, represent a major risk, since it is flammable and burns strongly and fast. Commercial flame retardants, developed in 1950-1980, significantly improve flame retardancy, but are highly toxic. For that reason, novel flame retardants are researched. Silica compounds have good thermal properties by giving residue after the combustion process. Therefore, in this paper silica precursors were investigated in order to reduce the current high quantities of flame retardants and to reach the full protection. Two silica precursors have been applied by sol-gel treatments on cotton fabrics and compared to conventional flame retardants applied by the pad-dry-cure process. Conventional flame retardant urea and ammonium hydrogen phosphate (Ap3) was applied in full (urea 240g/l and ammonium hydrogen phosphate 115 g/l) and half (urea 120g/l and ammonium hydrogen phosphate 57,5 g/l) concentration. Silica precursors Tetramethoxysilane (TMOS) and Tetraethoxysilane (TEOS) were applied in concentration of 15 ml/l. Additionally, silica precursor TMOS and TEOS were added to conventional flame retardant. The flame retardancy and burning behaviour were determinated according to standard methods – ISO 15025:2000 Textile fabrics – Burning behaviour – Determination of ease of ignition of vertically oriented specimens, and ISO 4589:1996 – Plastics – Determination of burning behaviour by oxygen index in Limiting Oxygen Index (LOI) Chamber (Dynisco). For better understanding the changes in cotton structure under the heat conditions thermogravimetric method (TGA) on Pyris1 (PerkinElmer) and micro combustion calorimeter (MCC) MCC-2, Govmark, USA were used. For the durability burning behaviour was tested after 1 washing cycle according to ISO 6330:2012 Textiles - Domestic washing and drying procedures for textile testing The mixture of silica precursors with urea and ammonium hydrogen phosphate resulted in higher flame retardancy even when half the concentration of conventional FR was applied. It can be concluded that the silica phase formed by sol-gel process plays a protective role to degradation of the cotton fibers and it is able to modify the thermal and combustion behaviour of cellulose. The best results were achieved with the mixture of flame retardants - silica precursor TEOS, urea and ammonium hydrogen phosphate.

Resume : The single jersey fabrics have been used for investigations. Four variants of knits with the same set of knitting machine where manufactured: variant I of single yarns, variant II of two folded single yarns, variant III of three folded single yarns and variant IV of four folded single yarns. 4 combinations of packets from variant I (single fabric, two layers of single fabric, three layers of single fabric and four layers of single fabrics), 2 combinations from variant II (single fabric and two layers of single fabric), single layer of variant III and single layer of variant IV were used in the horizontal flammability test. The burning time up to the start until fabric or upper layer of packet break-up were measured. It was established, that the number of yarns in the loop influences the flammability more than the number of layers. The burning time has a medium correlation with air permeability and surface density. However, two areas with the similar burning time and with very different values of air permeability or surface density were found, hence the same flammability is possible to achieve with very high difference of air permeability and surface density values.

Resume : The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R) crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80 % of UV-R gets absorbed, whilst in the remaining 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in the most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such are type of fiber, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. Based on electronically-excited state by energy of UV-R (usually 340-370 nm) the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm) of the spectrum. By absorbing UV-A radiation optical brightened fabrics transform this radiation to blue fluorescence what leads to better UV protection. Natural zeolites are rock-forming, micro porous silicate minerals. Applied as nanoparticles to textile surface scatter the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, are very resistant to washing and improve the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene derivate FWA was applied on cotton fabric in wide concentration range without/with the addition of natural zeolite or silicone - polydimethylsiloxane (PDMS). UV protection was determined in vitro through Ultraviolet protection factor, UPF. Additionally the influence to fabric whiteness and fluorescence was researched.

Resume : The primary cause of skin cancer is believed to be a long exposure to solar ultraviolet radiation (UV-R) crossed with the amount of skin pigmentation in the population. It is believed that in childhood and adolescence 80 % of UV-R gets absorbed, whilst in the remaining 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Textile and clothing are the most suitable interface between environment and human body. It can show UV protection, but in the most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such are type of fiber, fabric surface and construction, type and concentration of dyestuff, fluorescent whitening agent (FWA), UV-B protective agents, as well as nanoparticles, if applied. Based on electronically-excited state by energy of UV-R (usually 340-370 nm) the molecules of FWAs show the phenomenon of fluorescence giving to white textiles high whiteness of outstanding brightness by reemitting the energy at the blue region (typically 420-470 nm) of the spectrum. By absorbing UV-A radiation optical brightened fabrics transform this radiation to blue fluorescence what leads to better UV protection. Natural zeolites are rock-forming, micro porous silicate minerals. Applied as nanoparticles to textile surface scatter the UV-R resulting in lower UV-A and UV-B transmission. If applied with other UV absorbing agents, e.g. FWAs, synergistic effect occurs. Silicones are inert, synthetic compounds with a variety of forms and uses. It provides a unique soft touch, are very resistant to washing and improve the property of fabric to protect against UV radiation. Therefore, the UV protective properties of cotton fabric achieved by light conversion and scattering was researched in this paper. For that purpose, the stilbene derivate FWA was applied on cotton fabric in wide concentration range without/with the addition of natural zeolite or silicone - polydimethylsiloxane (PDMS). UV protection was determined in vitro through Ultraviolet protection factor, UPF. Additionally the influence to fabric whiteness and fluorescence was researched.

Resume : Functional textiles– from research and development to innovations and industrial uptake. Summary.