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Many flame retardants (FRs) are brominated, and many of them are considered toxic, persistent and/or bio accumulative. A switch to non-halogenated alternatives for textile finishing is considered beneficial, but there is little knowledge about their environmental impact, their health risks during the production process and those in their final use. A conventional and an alternative FR (based on dialkyl phosphono carboxylic acid amine and ammonium sulfamate; urea and organophosphonate PO(OH)2-R-PO(OH)2, respectively) were applied to cotton fabrics that could be in touch with the skin in their final use. Burning and thermal behaviors and dermal toxicity when exposed to skin rubbing are evaluated. Fabrics treated show that both FR products act as FRs. The increase in the thermal stability of the tissue that causes an increase in the decomposition temperature is a relevant effect associated with the application of the conventional FR in the tissue, while the most important effect of the alternative FR lies in the increase of the residue at 600°C, associated with the generation of fewer volatiles, which has an impact on the intensity of combustion. The study of the dermal toxic potential of FR-treated cotton bed sheets showed that the two tested products do not penetrate into the skin when applied under the conditions used and were safe when in contact with the skin. Moreover, the alternative FR seems to be safer when in contact with the skin considering also its higher concentration in the textile.

Recently, a significant interest in eco-friendly textile products and processes has been noted among consumers and producers. In this respect, nanobubble technology is emerging as a green alternative. In this study, water-repellent cotton fabrics were produced with exhaustion and nanobubble technology (e-flow method) using a short-chain fluoropolymer. The currently most developed substituents are based on molecules with short fluorine carbon chains. The wettability, mechanical properties, air permeability and treatment durability were evaluated. The untreated and treated cotton fabrics were analyzed with ATR-FTIR (Fourier transform infrared attenuated total reflectance) and SEM (scanning electron microscopy) to reveal chemical and morphological modifications. The obtained results show that cotton samples treated with short-chain fluoropolymers, nontoxic and eco-friendly finishing chemicals, and nanobubble technology have good water repellence and good washing durability. Due to their size and structure, nanobubbles possess distinct properties that make them particularly effective at improving water quality, enhancing water treatment processes, and improving productivity in industrial applications. Nanobubbles have a strong negative surface charge that keeps them stable in liquid, prevents them from coalescing, and enables them to physically separate small particles and droplets from water, such as emulsified fats, oils, and grease.

Raw hemp (Cannabis sativa L.) was subjected to alkaline delignification with the application of NaOH ranging from [0.125M] to [1M] for times from 5 to 480 min. Lignin contents of the original and delignified samples were determined. The samples were subjected to thermogravimetric analysis (TGA) under a N2 atmosphere with temperatures ramped from 25 to 600 °C at 10 °C min-1. Lignosulfonates samples of low, medium and high molecular weight were subjected to the same TGA and showed that lignin decomposed over the entire temperature range. The contributions of lignin to the mass loss during thermal decomposition of hemp and kinetics of lignin content and the most relevant TGA results were determined. Regression models estimating the lignin content of the fibers based on TGA results were formulated. These models allow for the prediction of mean lignin content within ± 0.1% (based on dry weight of pulp) in the central range of the experimental field.

Expandable graphite was applied to an upholstery polyester textile material as an eco-friendly flame-retardant alternative to halogenated compounds. Fabrics treated with the flame retardant were evaluated by flammability tests. Besides, thermal analysis was carried out by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Moreover, a percutaneous absorption study was conducted to verify the safety in terms of dermal penetration of the flame-retardant treated upholstery fabric for human use. The upholstery fabric treated with expandable graphite successfully passed the flammability tests. Thermogravimetric analyses with TGA and DSC showed that the flame-retardant application slightly decreased the initial decomposition temperatures regardless of the atmosphere but increased the final residue at 600°C (35.7% in O2 and 44.5% in N2) compared to non-treated upholstered fabrics. Dermal permeation of expandable graphite applied on the polyester fabric showed no penetration after 24 h of fabric exposure time. This result demonstrated that graphite-treated polyester fabric is dermatologically and toxicologically safe for use in upholstery. Applied expandable graphite proved an efficient and safe flame-retardant alternative to conventional flame retardants for eco-friendly flame resistance applications in upholstery fabrics.

Objective: The main aim of this study is to characterize the external lipids of different ethnic hairs and to study the contribution of the exogenous lipids on their physicochemical properties. Methods: On the extraction procedure, sebaceous lipids from the exterior of the fiber are removed. The influence of those free lipids on the hair properties, such as contact angle, mechanical characteristics, and sorption of water, will be evaluated to determine permeation characteristics of the keratin fibers. Relationship with lipid order was also determined by infrared spectroscopy (IR). Results: Lipid extraction indicates the greatest amount of total lipids for African hair. Caucasian lipid extracts present the higher melting point and phase transition temperatures. This could be related to higher hydration and lower diffusion coefficient of the Caucasian fibers. A decrease in moisture was found in the lipid-extracted fibers. This diminution of the maximum water regain in all cases could be due to a higher water desorption. IR results indicate that Caucasian and moreover African native fibers present the most quantity of lipids, and the similar frequency of all fibers indicates a lamellar/orthorhombic order arrangement. Conclusion: The hexane/tert-butanol extraction was demonstrated to modify not only cuticular but also cortex lipids. Exogenous lipid depletion in all fibers indicates a less water content and higher water desorption. However, lipid depleted Caucasian fibers presents an increase in the lipid order which could be related to the different saturation of the lipid extract and its improvement in breaking tenacity. © 2019 Wiley Periodicals, Inc.

The ease of cultivation, structure and properties of hemp (Cannabis sativa L.), provide it a great potential for industrial applications; nevertheless, the unfavourable high content of lignin complicates its processing, especially in the textile area. An appropriate knowledge of the delignification process would lead to treat hemp fibres as cotton fibres. In this work, hemp has been treated chemically with an alkaline bath with sodium hydroxide [1M], liquor ratio 1/15, during different times at 110 °C. Then, the content of lignin of the treated fibres was determined with the methodology of Tappi T222 om-15 standard and subsequently, the samples were analysed by thermogravimetry (TGA). Through the correlation analysis, the relationship between lignin content, onset temperature of cellulose decomposition and loss of mass of the different decomposition steps were found. Finally, the kinetics of alkaline hemp delignification by using the residual lignin after chemical treatments, and the kinetics of the different decomposition steps was determined, Postprint (published version)

Raw hemp fibres are alkaline delignified at different times in order to evaluate the effect of time of delignification on moisture uptake behaviour of hemp. Lignin content of samples is measured. Samples of original and delignified hemp are subjected to moisture absorption/desorption isotherms from 5% to 95% of relative humidity at 25ºC and moisture uptake behaviour is assessed through measuring the sorption ratio of delignified vs. original hemp. Hysteresis makes evident the greater influence of lignin in moisture binding at lower relative humidities, while at higher humidities cellulose plays the most important role. GAB, Hailwood-Horrobin and Dent models are fitted to absorption/desorption isotherms. Delignification decreases the size of the monolayer that depends on the way it has been measured: Size measured in desorption is always greater than that in absorption. Lignin greatly contributes to the growth of the size of the monolayer. The energy constants of the monolayer differ according to the used model: results of delignified fibre in absorption are higher than those of the original ones while the contrary occurs in desorption. Lignin causes great differences between absorption and desorption. The energy constants of the multilayer are identical for the three models showing greater range of variation in delignified samples than in the original ones. Results in absorption are higher than those in desorption. The level of relative humidity at which primary moisture uptake ties with the secondary one is determined and it has been observed that decreases with the energy constant of the multilayer, while primary and secondary regain at this level show a strong relationship with the size of the monolayer and growths with them, Postprint (author's final draft)

Raw hemp fibers are alkaline delignified to evaluate the effect of lignin on the moisture uptake behavior of hemp. Samples are subjected to moisture absorption/desorption isotherms from 5% to 95% relative humidity at three different temperatures (15, 25, and 35°C). The sorption ratio between delignified and untreated hemp is lowered by 25%. Hysteresis makes evident the greater influence of lignin on moisture binding at low relative humidity while at high relative humidity, cellulose plays the most important role. The GAB, Hailwood‐Horrobin and Dent models are fitted to absorption/desorption isotherms. Delignification and temperature decrease the size of the monolayer. The energy constants of the monolayer differ according to the model used. Lignin causes great differences between absorption and desorption. The greater the temperature is, the lower the monolayer energy constant. The energy constants of the multilayer are identical for the three models, showing a greater range of variation in delignified samples than in the untreated samples. Based on primary and secondary energy constants, bonding enthalpies are determined. Estimations in desorption show higher correlation coefficients with the energy constants, which enables to conclude that measures in desorption better explain the effect of delignification on the water uptake behavior of hemp.

Hemp (Cannabis sativa L.) is a plant of which, its ease of cultivation, structure and properties, provide it great potential for industrial applications; nevertheless, the unfavorable content of lignin complicates its processing, especially in the textile area. Thus, an appropriate knowledge of the delignification process would lead to treating hemp fibers as cotton fibers. In this work, hemp has been treated with an alkaline liquor [NaOH 1¿M] at 110¿°C during different times and afterwards, the substrates were chemically characterized in order to determine their lignin content and also analyzed by thermogravimetry (TGA). Through the correlation analysis, the relationship between lignin content, onset temperature of cellulose decomposition and loss of mass at the different decomposition steps were established. A hyperbolic kinetic model to explain the influence of alkaline treatment time on lignin content and also on the loss of mass at the four steps of decomposition of the samples by TGA up to 600¿°C has been developed. Although it has been found that the degradation of lignin occurred across the entire temperature range, results have shown that the influence of treatment time has become clearly relevant on lignin content, Step2 (180.5¿°C-273.5¿°C) where a fraction of 10 to 16% of lignin was degraded, and Step3 273.5¿°C-396.5¿°C) where cellulose was mainly decomposed and 20% of lignin was also degraded, Authors gratefully acknowledge the financial support for this research from the Ministry of Science and Innovation of Spain (Project MAT2016-79352-R) and from the National Secretary of Higher Education, Science, Technology and Innovation of Ecuador (SENESCYT) for Doctoral's Fellowship (No. CZ02-000926-2018), Postprint (author's final draft)

The influence of the alkaline delignification of hemp on its moisture uptake has been studied under the project “Preparation and functionalization of hemp for textile substrates” focussed on the reduction of cotton imports for the manufacturing of clothing, household textiles and medical devices. The project looks for the partial replacement of cotton by hemp on the production of natural cellulosic textiles. Hemp fibres are alkaline delignified at different times to evaluate its effect on their moisture uptake behaviour to evaluate the ability of replacing cotton in the next-to-skin goods manufacturing. The paper gives three easy tools to analyse the moisture uptake behaviour by determining the sorption ratio, the hysteresis and the parameters of the isotherms fitted using three different models (GAB, Hailwood-Horrobin and Dent) to the absorption desorption isotherms. The samples of the original and delignified hemp have been subjected to moisture absorption/desorption trials from 5% to 95% RH at 25 °C. Sorption ratio and hysteresis reveal the greater influence of lignin on moisture uptake at low relative humidities, while at high, was cellulose which plays the most important role. The models fitted to the isotherms show that delignification decreases the size of the monolayer that, in desorption results always greater than in absorption. The energy constants of the monolayer for delignified fibres in absorption were higher than those for the original fibres, while the opposite occurred in desorption. Lignin caused great differences between absorption and desorption. The energy constants of the multilayer show a greater range of variation in delignified samples than in the original one, and results in absorption were higher than those in desorption. Delignification time of 3 h reached the highest cellulose content which best approached to the cellulose content of cotton causing that the moisture uptake behaviour drew near to it, especially at higher relative humidit

Hemp (Cannabis sativa L.) is a plant of which, its ease of cultivation, structure and properties, provide it great potential for industrial applications; nevertheless, the unfavorable content of lignin complicates its processing, especially in the textile area. Thus, an appropriate knowledge of the delignification process would lead to treating hemp fibers as cotton fibers. In this work, hemp has been treated with an alkaline liquor [NaOH 1 M] at 110 °C during different times and afterwards, the substrates were chemically characterized in order to determine their lignin content and also analyzed by thermogravimetry (TGA). Through the correlation analysis, the relationship between lignin content, onset temperature of cellulose decomposition and loss of mass at the different decomposition steps were established. A hyperbolic kinetic model to explain the influence of alkaline treatment time on lignin content and also on the loss of mass at the four steps of decomposition of the samples by TGA up to 600 °C has been developed. Although it has been found that the degradation of lignin occurred across the entire temperature range, results have shown that the influence of treatment time has become clearly relevant on lignin content, Step2 (180.5 °C-273.5 °C) where a fraction of 10 to 16% of lignin was degraded, and Step3 273.5 °C-396.5 °C) where cellulose was mainly decomposed and 20% of lignin was also degraded.

In textile printing, hydrotropic components are usually added to print paste formulations promoting the hydration of textile fabrics by disrupting the hydrogen bonding network between water molecules. For this purpose, urea is commonly used but nevertheless, its presence causes water eutrophication and their reduction or replacement by more environmentally-friendly products is required. In the present work, we have studied an alternative hydrotropic product (polyethylene glycol, PEG) to replace urea. A factorial design of experiments has been carried out to identify the factors that optimize several variables of interest such as viscosity of the printing paste and fabric colour strength. The results showed that a reduction of 70 wt% of urea was achieved by using PEG 400, while preserving the performance of printing formulation. The viscosity of these eco-friendly printing paste formulations was similar to that of the original urea-based formulations and, more interestingly, fabrics showed similar colour strength and fastness to those of fabrics printed by the conventional method.

Los Retardantes de Llama (FR, flame retardants) son un grupo de contaminantes ambientales antropogénicos que se utilizan a concentraciones relativamente altas en muchas aplicaciones. Actualmente, la mayoría de productos FR son bromados, y muchos de ellos se consideran tóxicos, persistentes y bioacumulativos. Las alternativas no halogenadas son una posible solución para el problema, pero hay poco conocimiento sobre su impacto ambiental, sus riesgos para la salud durante el proceso de producción y en su uso final. El principal objetivo del proyecto LIFE-FLAREX es contribuir a la mitigación de los impactos ambientales y de salud causados por los compuestos tóxicos resultantes de los productos de acabado de textiles FR que contienen bromuro, formaldehído y/o antimonio, mediante el análisis técnico y ambiental de su aplicación industrial, así como el estudio de productos alternativos y tecnologías innovadoras para obtener propiedades retardantes de llama similares. En el IQAC-CSIC se ha evaluado la toxicidad de estos acabados cuando un tejido tratado está en contacto con la piel humana, donde la vía dérmica es una de las vías más importantes para la penetración de los compuestos, esto se ha estudiado mediante la metodología de absorción percutánea, calculando después el MoS (Margen de seguridad) de cada FR. También se han caracterizado los tejidos tratados mediante técnicas calorimétricas para estudiar el comportamiento de los FR.

Flame Retardants are a group of anthropogenic environmental contaminants used in textile finishing’s. Currently, the largest marked group of FRs is brominated FR considered toxic, persistent and bio accumulative. Non-halogenated alternatives are a possible solution, but there is a lack of knowledge concerning environmental impact and health risks. The aim of this study is focused on dermal absorption of FR in order to calculate the Margin of security for textile fabrics treated with flame retardant finishing’s. FR based on sulfamate ammonium were used applied onto cotton and polyester fabrics. Both have been demonstrated that they are dermal safety for human at the conditions used.