Noémia Carneiro

Polymer Nanocomposites for Multifunctional Finishing of Textiles – A Review

Improvement of existing properties and the creation of new material properties are the most important reasons for the functionalization of textiles. Polymer nanocomposites offer the possibility of developing a new class of nanofinishing materials for textiles with their own manifold of structure property relationship only indirectly related to their components and their micron and macro-scale composite counterparts. Though polymer nanocomposites with inorganic filler of different dimensionality and chemistry are possible, efforts have only begun to uncover the wealth of possibilities of these new materials. Approaches to modify the polymer nanocomposite system by various inorganic or organic substances can lead to a huge number of additional functionalities which are increasingly demanded by the textile industries. In this review, we have compiled the current research in polymer nanocomposite-based nanofinishes for multifunctional textiles which provides a snapshot of the current experimental and theoretical tools being used to advance our understanding of polymer nanocomposites and their applications in textiles.

Application of nanotechnology in antimicrobial finishing of biomedical textiles

In recent years, the antimicrobial nanofinishing of biomedical textiles has become a very active, high-growth research field, assuming great importance among all available material surface modifications in the textile industry. This review offers the opportunity to update and critically discuss the latest advances and applications in this field. The survey suggests an emerging new paradigm in the production and distribution of nanoparticles for biomedical textile applications based on non-toxic renewable biopolymers such as chitosan, alginate and starch. Moreover, a relationship among metal and metal oxide nanoparticle (NP) size, its concentration on the fabric, and the antimicrobial activity exists, allowing the optimization of antimicrobial functionality.

Preparation of cotton materials using CORONA discharge

Abstract The present work concerns the study of preparation processes when this operation is preceded by a CORONA discharge made on dry raw fabrics. The influence in the whiteness degree, hydrophility, starch removal and uniformity of properties of the cellulosic material after preparation is studied. Combined preparation processes are widely used in order to replace solutions where desizing, alkaline boiling and bleaching are individual operations, being a main interest to find the optimal conditions to achieve alkaline oxidative treatments with an uniform and more intense cleaning action. CORONA discharge is able to strongly modify hydrophility of cotton fabrics in raw stage, which is determinant to increase liquids absorption and uniformity of processed fabrics. Results of long-bath, pad-roll, pad-batch and pad-steam bleaching processes in laboratory conditions are compared using or not wetting agent in the recipes and including CORONA discharge as a preparation operation. The transfer of this technology to industry regarding the implementation in textile plant in a very near future is being worked, supported by results as the present ones.

Poliamid Boyama İşleminde DBD Plazma Modifikasyonunun Etkisi

In this work, a study of the dyeing of polyamide fabrics after surface modification by dielectric barrier discharge (DBD) plasma treatment was performed. Physical and chemical properties of the textile substrate were characterized before and after plasmatic modification, showing important changes in water contact angle, hydrophility, chemical surface composition and morphology. Dyeing properties with direct dyes were evaluated by means of dyebath exhaustion, color strength and washing fastness tests, demonstrating that plasma treated fabrics can achieve excellent dye uptake, high rate of dyeing and good uniformity, good fastness levels, meaning a great challenge and opportunity for industrial application.

Reactive pad-batch dyeing in CORONA discharged fabrics

Abstract The present work aims to the study of the increase of pick-up, together with uniformity degree, concerning the application of reactive dyeing baths by padding in a dry cotton fabric previously treated with CORONA discharge. Dyeing recipes, with and without wetting agent, are compared and advantages of CORONA discharge are analysed. Reactive dyes are used, expecting also to increase washing fastness of the difficult dark colours due to higher penetration of the dye into the core of the fibres when submitted to plasmatic treatment. The use of CORONA discharge intends to modify hydrophility of cotton fabrics even when they are presented to padding in hydrophobic state. A good alternative to wetting agent presence in recipes is found and more uniform and intense dyeings are performed in all cases.

Polyamide 6.6 Modified by DBD Plasma Treatment for Anionic Dyeing Processes

Plasmatic double barrier discharge (DBD) obtained in air at atmospheric conditions is widely used, among other non-thermal plasmatic alternatives, to modify chemical and physical properties of different textile polymers (Morent et al., 2007). The impacts of DBD on environmental aspects of textile processing rise to get high attention due to important reduction of costs in dyeing by savings in processing times, products, human resources, water and energy (Carneiro et al., 2001). All fibers, from natural to synthetics, can be submitted to several irradiation methods with diverse and significant meaning in different areas of textile processing (Sparavigna, 2001). The effects on surface are reported for cellulosic fibers (Carneiro et al., 2005; Souto et al., 1996), wool (Rakowski, 1992), polyester (Oktem et al., 2000, Leurox et al., 2009), polyamide 6.6 (Papas et al., 2006; Oliveira et al., 2009), polyamide 6 (Dumitrasku & Borcia, 2006), polytetrafluoroethylene (Liu et al., 2004), polyethylene (Oosterom et al., 2006), polypropylene (Yaman et al., 2009) and meta aramid (Chen et al., 2008), being roughness, microporosity and creation of polarity by oxidation mechanisms the main modifications induced by several types of irradiation techniques. Acid dyes are the most common in use for polyamide dyeing, but some problems are very well known, as difficulties to manage uniformity and fastness. The necessary pH to achieve a good exhaustion of dye in the fiber must be carefully controlled and sometimes is excessively low. Reactive dyes are very important for the dyeing of cellulosic and protein fibers, but in polyamide the results are not equivalent due to paler colors obtained (Soleimani et al., 2006). Reactive dyes for cellulose are similar to acid dyes in their chromophoric structure, but they possess reactive groups able to react chemically with the fiber in the presence of alkali. Only few of these dyes have been developed for polyamide application with ability to react with amino groups in fiber structure without the need of alkaline fixation. Stanalan (Dystar) and Eriofast (Ciba) are well known dyes for this purpose. Reactive dyes for cotton fibers, Procion (Dystar), Kayacelon (Nippon Kayaku), and Drimarene (Clariant) were tested for polyamide dyeing at boiling temperature and different pH showing distinct results. At pH 4, the most convenient result was obtained due to a high protonation of nucleophilic amino groups, contributing to electrostatic attraction between anionic dye and positively charged fiber (Soleimani et al., 2006).

Double dielectric barrier (DBD) plasma-assisted deposition of chemical stabilized nanoparticles on polyamide 6,6 and polyester fabrics

The development of new multifunctional textiles containing nanoparticles (NPs) has a special interest in several applications for pharmaceutical and medical products. Cu, Zn and Ag are the most promising antimicrobial NPs, exhibiting strong antibacterial activities. However, most of antimicrobial textiles coated with NPs are not able to perform a controlled release of NPs because of the high degree of aggregation. The aim of this study is to assess the effect of NPs stabilizers such as citrate, alginate and polyvinyl alcohol (PVA) in Cu, Zn and Ag NPs dispersions. The obtained dispersions were used to develop a new class of antibacterial NPs coatings onto polyamide 6,6 (PA66) and polyester fabrics (PES) by Double Dielectric Barrier (DBD) plasma discharge. Dynamic light scattering (DLS) was used to evaluate the best dispersing agent in terms of size, polydispersity index and zeta potential. Coating efficiency was evaluated by SEM, XPS and FTIR. The washing fastness of the coatings developed was also tested. The results show that the best dispersions were obtained using 2.5% of citrate for ZnO, 5% Alginate for Cu and 2.5% alginate for Ag NPs. SEM, XPS and FTIR analysis shows that DBD is an efficient deposition technique only for Ag and Cu NPs and that better perform in PA66 than PES fabric. The DBD deposition in air display similar results in term of NPS deposition of usually more efficient plasma jets using carrier gas such as N2 and Ar.

Synthesis and Characterization of Poly (N-Isopropylacrylamide) Zno Nanocomposites for Textile Applications

Department of Science and Technology (DST), India and Fundacao para a Ciencia e a Tecnologia (FCT), Portugal .