Production, characterization and application of nano - phase change materials: a review

Phase Change Materials (PCMs) for heat storage and energy saving has been extensively used in many fields for heating and cooling processes, including building, solar energy, textiles, agriculture, and electronics. PCMs have been getting incredible attention for being low-cost materials and have potential materials for thermal energy storage (TES) with long cycle life. Though, the disadvantages such as flow, result in encapsulation in three scales of Macro, Micro and Nano capsules. Encapsulating PCM reduces the disadvantages and improves the efficiency of PCMs. Different methods for producing PCMs in the scale of nano and core-shell materials, have been developed and the capsules size in relation to parameters such as pH, stirring rate, material selection and preparation method have been investigated. In recent years, this subject has been extensively studied, seeking to find more efficient and safer PCMs. In this context, nanoscale PCMs have been produced and applied to the most diverse products and their performance evaluated. They simply modified and optimized production processes. The novelty of this study lies in the fact that merely a few articles have reviewed nano-encapsulating of PCMs, focusing on new developments on PCM nanocapsules. Moreover, few articles have compared nano and microcapsules of PCMs so far. The analysed papers suggest that the production methods influence the size of the obtained capsules. The purpose of this article is to make an updated review of the synthesis and application of nano-encapsulated PCMs

Systematic review of wound dressings: a movement from the past to the present

This systematic review aims at investigating different wound dressings commonly used for the healing process and skin repair. Five databases, namely SCOPUS, Web of Science, Medline, Google Scholar, and Cochrane Database of Systematic Reviews, up to 2020, were scanned for papers specific to the topic of concern. The blinded randomized controlled trials, in vivo and in vitro studies comparing common wound dressings, including traditional, natural/biological, and artificial ones were studied in the present review. Finally, the researchers selected 22 studies. From which the data related to the clinical features of wound dressings and their advantages and disadvantages) were derived. The review of literature suggests that many treatment combinations are utilized as wound dressings based on the wound type and hospital guidelines. Nevertheless, there are conflicting views about the most appropriate choice. The findings of the reviewed articles indicate that hydrogels are the most common wound dressing used for wounds and burns due to high thermal/mechanical stability and low water evaporation. However, it is suggested to apply hybrid hydrogel membranes to overcome the low mechanical strength of a single component

Contribution to an efficient transmission of information to the textile fashion consumer and the influence in sustainable attitudes

The concepts involved in sustainable textile fashion, demanding good knowledge about raw materials, processes, end use properties and circuits amongst others, are able to determine the way the textile product is designed and the behavior of the consumer, regarding life style and buying decisions. The textile product`s life integrates raw materials, their processing, distribution, use by the consumer and destination of the product after useful lifetime, this is, his complete life cycle. It is very important to recognize the power of the consumer to influence parameters related to sustainability, namely when he decides how, when and why he buys and afterwards by the attitudes taken during and after use. The conscious act of consumption involves ethical, ecological and technical knowledge in which the concern is overall lifecycle of the fashion product and not exclusively aesthetic and symbolic values strongly related with its ephemeral nature. The present work proposes the classification of textile products by means of an innovative label aiming to establish a rating related to the Life of Fashion Products, by using parameters considered with especial impact in lifecycle, as textile fibers, processing conditions, generated wastes, commercialization circuits, durability and cleaning procedures. This label for sustainable fashion products aims to assist the stakeholders with informed attitudes and correct decisions in order to promote the objectives of sustainable fashion near designers, consumers and industrial experts.This work is financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the projec

Aplicação de sistemas enzimáticos à degradação de corantes têxteis

Tese de doutoramento em Engenharia Têxtil.Os problemas ambientais associados à industria têxtil derivam, sobretudo, do uso de corantes orgânicos. Um grande numero destes compostos são recalcitrantes e apresentam caracter carcinogénico e mutagénico. A descoloração de corantes têxteis pode ser levada a cabo por enzimas que são na natureza produzidas por microorganismos. As enzimas oxidativas, nomeadamente as lacases provenientes de fungos de degradação branca, tem vindo a despertar particular atenção mas os estudos documentados dizem normalmente respeito a extractos brutos de fungos e não enzimas puras. Assim, atendendo à diversidade de enzimas produzidas e à especificidade destes processos, a investigação neste domínio tem-se confrontado com numerosas dificuldades, nomeadamente no esclarecimento das reacções envolvidas e na definição dos factores que as influenciam. Nesta dissertação, estudou-se a acção da lacase na descoloração de corantes têxteis. Usou-se, para isso, uma preparação comercial, o DeniLiteTM,usado na industria têxtil no acabamento de produtos tingidos com índigo, contendo para além da lacase, um mediador (ácido fenotiazina-10-propiónico) e um surfactante não iónico (de origem indeterminada). Foi ainda avaliada comparativamente a acção da lacase isolada desta preparação por um processo filtração por gel. A enzima isolada ainda que apresentando uma menor estabilidade térmica, comportou-se de maneira semelhante no que se refere aos perfis de pH e temperatura. Os corantes antraquinónicos representam uma importante classe de corantes têxteis. Atendendo às suas características químicas são difíceis de biodegradar. Escolheu-se o corante Remazol Brilliant Blue R, para representar este grupo de compostos nos estudos de degradação com lacase. A formulação comercial descolorou o corante em contraste com a lacase isolada que não revelou qualquer acção na remoção de cor. Esse facto determinou a necessidade de analisar o efeito do mediador e do detergente não iónico incluído na preparação comercial neste processo. Para isso, estudou-se comparativamente o efeito de três surfactantes não iónicos, Triton X-100, Brij 35 e Tween 20, em concentrações abaixo das respectivas concentrações mícelares críticas. Os resultados obtidos comprovam a não influência destes compostos na descoloração enzimática do corante. A adição do mediador foi determinante para que a descoloração do corante ocorresse. Dos mediadores estudados, promazina, ácido violúrico e N-hidroxibenzotriazole, o segundo foi o que se apresentou mais eficaz, permitindo a descoloração completa do Remazol Brilliant Blue R ao comprimento de onda de absorção máxima em apenas 20 minutos, cerca de duas vezes mais rápido que com o dobro da concentração de N-hidroxibenzotriazole em iguais condições experimentais. A promazina, apesar da semelhança química com o ácido fenotiazina-10-propiónico, não mediou o processo de descoloração do corante. Estudou-se o efeito da estrutura química de corantes azo na descoloração com a lacase. Para isso sintetizaram-se sete novos corantes disazo, todos eles com um grupo hidroxilo na posição para em relação à ligação azo, variando os substituintes no anel fenólico. Destes compostos, só os que eram solúveis em água, ou seja, os que continham grupos sulfónicos na molécula, é que são substratos da lacase. De entre os corantes soluveis, aqueles que incluíam grupos dadores de electrões no anel fenólico, do tipo metoxilo, eram descolorados pela lacase enquanto que no corante com substituínte carboxílico foi necessária a presença do ácido violúrico para que a descoloração ocorresse. O N-hidroxibenzotriazole não apresentou qualquer efeito na catálise enquanto o ácido violúrico acelerou as reacções de descoloração destes corantes. Os resultados deste estudo levou-nos a propor um mecanismo de biotransformação de corantes disazo com a formação de um corante mono azo e benzoquinona. A consciência da necessidade de explorar o efeito sinergético de várias enzimas para se obter a mineralização de corantes ou outros compostos resultantes da degradação destes, escolheram-se duas oxidases, a glucose-1-oxidase e a glucose-2-oxidase e analisou-se o seu efeito na catálise de diferentes compostos quinónicos. Foi interessante notar que as duas oxidases foram capazes de reduzir as quinonas ainda que a glucose-2-oxidase , tipicamente encontrada nos fungos de degradação branca, tenha sido mais eficaz. Os resultados foram discutidos no contexto da degradação oxido-redutora de corantes complexos poliaromáticos. o conjunto de resultados sugere que a natureza robusta da lacase e a sua disponibilidade podem tomar possíveis aplicações em escala alargada na descoloração de águas residuais têxteis.The deleterious environmental impact of the textile industry is largely due to the use of organic dyes. The vast majority of these dyes are recalcitrant and have the potential to form carcinogenic and mutagenic compounds. The decolorization of textile dyes can be catalysed by enzymes produced from microorganisms. Oxidative enzymes, namely laccases from white-rot fungi have been the subject of much work but the main thrust of this work has been done using crude fungal extracts, and much less has been done using purified laccases. Therefore, taking into consideration the diversity of enzymes produced and the specificity of such processes, research in this area has had to deal with numerous variables that include understanding the reactions involved and the factors that influence these reactions. In this dissertation, the effect of laccase on the decolorization of textile dyes was studied. To this effect, a commercial formulation called DeniLiteTM used in the textile industry finishing process for indigo-stained cloths, which contained laccase, a mediator and a non-ionic surfactant, were employed. Gel filtration chromatography of the preparation made it possible to study the effect of the laccase alone. The purified laccase showed slightly lower thermal stability than the commercial laccase preparation. The pH and temperature profiles of the two preparations were similar. Anthraquinone dyes represent an important class of textile dyes. However, their chemical properties make them difficult to degrade. Remazol Brilliant Blue R was selected as a representative of this class of dyes in studies on biodegradation with laccase. The commercial laccase formulation decolorized this dye whereas its laccase alone did not do soo. This prompted the need to study the effect of mediators and of nonionic detergents that were present in the commercial formulation. The effect of three non-ionic surfactants, Trition X-100, Brij 35 and Tween 20 were studied at concentrations below their critical micelle concentrations. The results indicated that these did not play a role in the decolorization processo. On the other hand, the addition of mediator was found to be critical for decolorization to occur. Among the potential mediators studied, namely, promazine, violuric acid and N-hydroxybenzotriazole, the second was found to be the most effective. Using violuric acid, complete decolorization was obtained after about 20 min. determined at the absorption maxima of the dye. Promazine, although chemically similar to phenothazine-l0-propionic acid present in the commercial formulation, was not a suitable mediator for the decolorization processo. The relationship between the chemical structures of several disazo dyes and their biodegradability by laccase was studied. To perform this study, seven novel disazo dyes were synthesized. Each had a hydroxyl group in the para position in relation to the azo bond, whereas other substituents on the phenolic ring varied. Among these compounds, only the four water soluble compounds, which had a sulfonic group, were suitable substrates for laccase. Those which had electron donating groups in the phenolic moiety, such as methoxy groups, were readily decolorized by laccase. The dye with a carboxylic substituent required the presence of the mediator violuric acid in order for decolorization to occur. N-hydroxybenzotriazole did not affect the laccase-catalyzed reaction, whereas in general violuric acid increased the velocity of the laccase-mediated decolorization of the dyes. The need to study the synergistic effect of various enzymes in order to obtain dye mineralization led to the study of two oxidases, namely, glucose l-oxidase and glucose 2-oxidase. A study was carried out using model quinones of different chemical composition. Interestingly, both of the oxidases were able to reduce the quinones, although glucose 2-oxidase, typically found in white-rot fungi, was more effective. These results are discussed within the context of the oxido-reductive degradation of complex polyaromatic dyes. Taken together, the results suggest that the robust nature of the laccase and its ready availability might make it suitable for larger scale applications in the decolorization of industrial textile wastewater

Antimicrobial composite wound dressing

Nowadays, a wound dressing is no longer a passive material, it must interact with the wound and improve the healing process. In fact, the actual requirements for a wound dressing are quite challenging. To achieve these demanding goal, wound dressing’ research have been focus on the development of composites that combine the best of two or more polymeric materials. Thus, our group developed a composite material of cotton functionalized with hydroxypropyl methylcellulose / cyclodextrins hydrogel to be used as antimicrobial wound dressing. Hydrogel polymer will improve the wearability and the drug delivery capacity of cotton textiles. And cotton will enhance the mechanical properties of hydrogel, facilitating the handle process. The composite synthesis was performed by one-step chemical crosslinking. The reaction parameters, such as crosslinker concentration and polymeric solution concentration, were optimized. The obtained composites were characterized base on their physicochemical and biological properties. To the best of our knowledge, loading and release of gallic acid (as antibacterial agent) into composites wound dressings, and its release for control wound infections, have not been evaluated until now. The developed composites have the combined properties of cotton and hydrogel. The gallic acid was successfully loaded into the polymeric network, and it release was sustained for 48 h. The loaded composites can destroy bacterial cells preserving the gallic acid antibacterial activity. Thus, the developed composites showed suitable properties for the incorporation of gallic acid and utilization as antibacterial wound dressing.TSSiPRO—NORTE-01-0145-FEDER-000015—supported by the regional operational program NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund;info:eu-repo/semantics/publishedVersio

Modification of polyamide 6.6 dyeing properties by grafting with poly(acrylic acid)

978-972-8063-67-2The wet chemical surface modification continues to be a growing area of research interest. This study describes preparation and characterization of poly (acrylic acid)-grafted polyamide 6.6 fabric. Poly(acrylic acid) has been grafted onto polyamide backbone using benzoyl peroxide (BPO) as catalyst in aqueous medium. The benzoyl peroxide initiator optimum concentration was 0.03 M. The best conditions for optimum grafting reaction were reaction time 120 min, grafting temperature 85°C, monomer concentration 0.5 M and BPO concentration 0.03 M. The grafting rate was evaluated gravimetrically. The maximum grafting percentage obtained was 13.3%. All samples were characterized by Fourier–transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The influence of acrylic acid grafting onto polyamide 6.6 was studied in terms of dye uptake using a basic dye, Rouge Maxilon GRL. Mechanical properties were also analysed

Influence of different finishing treatments over mechanical and thermal properties of bed linen

This work aims to assess the relationship between the mechanical and the thermal properties of summer bed linen using different softener formulations in home textiles finishing. Objectively, we intend to study the effect of different softeners and their concentrations, based on non-ionic polyethylene dispersions and a cationic silicone softener micro-emulsion on textile properties. The research shown that thermal related properties are influenced by polyethylene softeners, while the silicone softener influences the mechanical behavior of the tested samples. Finally, selected softened samples of bed linen were evaluated by a dry thermal manikin to validate some conclusions.(undefined

Green dyeing of polyamide with increased anti-UV properties

[Excerpt] Introduction: During the last few decades, ecological concerns related to the use of the synthetic dyes, have led to a greater motivation for the development of processes that use natural products. This strategy has been applied to improve theincreasingly necessary sustainability of wet textile processes.Natural dyes are available in nature in different shadesandthey can be exploited for coloring textilesandto improveother properties such as UV protection and antimicrobial activity. Among them, those obtained from eucalyptus leaves, mainly composed by tannins (gallic acid and ellagic acid) and flavonoids (quercetin and rutin), appear to be interesting for textile finishing applications. The eucalyptus leaves, arean abundant, inexpensiveand readily available forestresidue.However, despite the recognized properties of this type of compound, its use in polyamide dyeing was not reported in our literature review.The present study aimed to develop dyed polyamide 6 knittedfabrics with increased UV protection using a naturaleucalyptus leavesextract. [...]Authorswishing to acknowledge the Project UID/CTM/00264/2019 of 2C2T –Centro de Ciência e Tecnologia Têxtil, funded by National Founds through FCT/MCTES

Functionalization and characterization of cotton with phase change materials and thyme oil encapsulated in beta-cyclodextrins

The aim of this work was to study the production of comfortable cotton plain-weave fabrics withantibacterial and antifungal characteristics through a simple finishing process, which consists in apply-ing microcapsules of phase change materials (mPCM), monochlorotriazinyl- -cyclodextrin (MCT- -CD)and thyme oil. The fabrics were characterized by Infrared Spectroscopy (FTIR), Differential ScanningCalorimetry (DSC), Contact Angle and Infrared Thermography. The thyme oil release was also analyzed,as well as the antibacterial and antifungal activity. The materials treated with 20 L/mL of thyme oilhave shown anomalous oil release mechanisms, according to the Korsmeyer-Peppas model, and activityagainst Staphylococcus aureus, Escherichia coli, Trichophyton rubrum, Pseudomonas aeruginosa and Candidaalbicans.Therefore, it was reached the conclusion that mPCM, conjugated with thyme oil encapsulated in MCT- -CD, proved to be an interesting option to produce materials possessing thermoregulation propertieswith putative clinical relevance for the prevention of infections, particularly dermatophytosis.The main author wishes to express thanks to the CNPq-Brazil (Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brasil / National Council of Scientific and Technological Development – Brazil) for the doctoral scholarship (233550/2014-3). This work is also funded by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136 This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the program PT2020.info:eu-repo/semantics/publishedVersio

Cost and efficiency analysis of commercial softeners in the sewability behavior of cotton fabrics

This paper reports a comparative case study on the use of different softening products for bed linen fabrics, specifically regarding the sewability of the fabrics. The market offers a wide variety of commercial formulations of softeners for this purpose, but the composition and price varies considerably. This work was aimed to assess the relationship between the cost and effectiveness of different softener formulations in home textiles finishing. Objectively, the effect of different softeners and their concentrations on sewability of the fabrics was studied. Non-ionic polyethylene dispersions and a cationic silicone softener micro-emulsion in different concentrations and combinations were considered in this investigation. It was found that a combination of silicone and polyethylene based softeners presents the most interesting cost/performance behavior.This work has been funded by FEDER through Programa Operacional Factores de Competitividade - COMPETE and by national funds by FCT - Fundacao para a Ciencia e a Tecnologia in the context of project PEst-C/CTM/UI0264/2011