Održan 14th Symposium „Novel technologies and economic development“

U radu je dan prikaz 14th Symposium „Novel technologies and economic development“ održan u Leskovcu, Srbija 22.-23. listopada 2021. godine

Održan 14th Symposium „Novel technologies and economic development“

U radu je dan prikaz 14th Symposium „Novel technologies and economic development“ održan u Leskovcu, Srbija 22.-23. listopada 2021. godine

LIGHT CONVERSION AND SCATTERING IN UV PROTECTIVE TEXTILES

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 most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, 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 340370 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 420470 nm) of the spectrum. By absorbing UV-A radiation, optical brightened fabrics transform this radiation into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters 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, is very resistant to washing and improves 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-derived FWAs were applied on cotton fabric in wide concentration range without/with the addition of natural zeolite or silicone polydimethylsiloxane. UV protection was determined in vitro through ultraviolet protection factor. Additionally, the influence to fabric whiteness and hand was researched

Light Conversion and Scattering in UV Protective Textiles

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 most cases it does not provide full sun screening properties. UV protection ability highly depends on large number of factors such as type of fibre, 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 into blue fluorescence, which leads to better UV protection. Natural zeolites are rock-forming, microporous silicate minerals. Applied as nanoparticles to textile surface, it scatters 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, is very resistant to washing and improves 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-derived FWAs were applied on cotton fabric in wide concentration range without/with the addition of natural zeolite or silicone- polydimethylsiloxane. UV protection was determined in vitro through ultraviolet protection factor. Additionally, the influence to fabric whiteness and hand was researche

Influence of Cotton Pre-Treatment on Dyeing with Onion and Pomegranate Peel Extracts

In this paper the possibility of applying natural dyes on cellulose fibres were researched with respect to the impact of cotton material pre-treatment (scouring, chemical bleaching, mercerization and mordanting), using renewable sources of natural dyes (waste as a source). As mordants, metal salts of copper, aluminium and ferrum were used, and the influence on colour change as well as on fastness properties were analysed. The natural dyes were extracted from onion peel (Allium cepa L.) and pomegranate peel (Punica granatum L.). In spectrophotometric analysis performed of the plant extracts, the onion extract has peaks at 400 and 500 nm, resulting in red-orange colourations and the pomegranate extract shows a maximum at 400 nm, i.e., in the yellow region, which is characteristic of punicalin. Results show significant influence of cotton pre-treatments on colour appearance and fastness properties, caused by pre-treatments affecting the properties and structure of the cotton itself. The positive effect of mercerization on dye absorption and bonding is confirmed. For wash and light fastness properties, more satisfactory results have been obtained for yarns dyed with pomegranate peel natural dye, and the key importance of mordants for fastness properties has been confirmed

Sustainable Alkaline Hydrolysis of Polyester Fabric at Low Temperature

High crystallinity leads to low hydrophilicity of fabric made of (poly(ethylene terephthalate)) fibers (PET) causing problems in finishing, washing, and dyeing processes. To improve these properties, the surface of PET fibers is usually modified by hydrolysis. Alkaline hydrolysis is a conventional process usually performed at a temperature higher than 100 °C for more than 1 h. However, the use of strong alkali and high processing temperatures (>100 °C) can lead to fabric damage and a negative impact on the environment. Therefore, in this paper, the possibility of hydrolysis of the PET fibers in the fabric in a sustainable, energy-efficient process was researched. The influence of low temperature (60–100 °C) and an accelerator (a cationic surfactant HDTMAC) to PET alkaline hydrolysis was studied through weight loss, the loss in breaking force, and fiber morphology. The kinetics of PET dissolution in 1.5 mol cm−3 NaOH at low temperature with and without the addition of HDTMAC was determined and the activation energy was calculated according to the theoretical model. It has been confirmed that PET hydrolysis can be carried out in 1.5 mol cm−3 NaOH with the addition of HDTMAC as an accelerator at 80 °C for 10 min. This process is more economically and energetically acceptable than the conventional process, and is therefore more sustainable

Thermal behaviour and flame retardancy of monoethanolamine-doped sol-gel coatings of cotton fabric

Recent studies have shown that the combustion behaviour of cellulose-based materials can be strongly affected by the presence of a protective phosphorus-rich silica coating obtained with a promising sol-gel approach. Thus, in the present work, monoethanolamine (MEA) was used in combination with diethylphosphatoethyltriethoxysilane sol-gel precursor (DPTES) to investigate both the ability of MEA to neutralize the acidic conditions of DPTES sol before cotton fabric treatment and the fire resistant properties of the obtained coating (COT-A). Moreover, to study the influence of an inorganic–organic silica matrix on the durability of the proposed flame retardant finishing, the DPTES-MEA sol was mixed with tetraethoxysilane (TEOS) and 3-glycidoxypropyltriethoxysilane (GPTES) precursors, to produce hybrid coatings on cotton fibres (COT-B). Scanning Electron Microscope (SEM) and Attenuated Total Reflection-Infrared (ATR-IR) spectroscopy were used to characterize the surface morphology, as well as the chemical structure of the treated and untreated fabrics. Furthermore, thermogravimetric Analysis (TGA), Microscale Combustion Calorimeter (MCC), and Limiting Oxygen Index (LOI) were performed on the treated cotton fabrics with a promising outcome. The results showed that DPTES-MEA sol is able to enhance the thermal and thermo-oxidative stability of cotton, exploiting the joint effect of thermal shielding (exerted by the silica phases) and char-forming (exerted both by the phosphoric acid source present in the alkoxysilane precursor and by the nitrogen content in MEA). Both proposed sol-gel treatments allow the cotton samples to achieve a LOI value of 29, classifying them as self-extinguishing materials

Effect of monoethanolamine and silica additives on flame retardant action of diethylphosphatoethyl-triethoxysilane on cellulose based fabric

Recent studies have shown that the combustion behaviour of cellulosic substrates can be strongly affected by the presence of a protective phosphorus-rich silica coating obtained with a promising sol- gel approach. Thus, in the present work, monoethanolamine (MEA) was used in combination of diethylphosphatoethyltriethoxysilane (DPTES) with the aim to investigate both the ability of MEA to neutralize the acidic conditions of DPTES sol before cotton fabric treatment and the fire resistant properties of the obtained coating. Moreover, to study the influence of an inorganic–organic hybrid matrix on the durability of the proposed flame retardant finishing, the DPTES-MEA sol was mixed with tetraethoxysilane (TEOS) and 3-glycidoxypropyltriethoxysilane (GPTES) precursors, to produce hybrid silica coatings on the cotton fibres. Limiting Oxygen Index (LOI), thermogravimetric Analysis (TGA), microscale combustion calorimeter (MCC), were performed on the treated cotton fabrics. The results showed that DPTES-MEA sol is able to enhance the thermal and thermo-oxidative stability of cotton, exploiting the joint effect of thermal shielding (exerted by silica phases) and char-forming

Sodium metasilicate for improvement cotton flame retardancy

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