Microgel-based surface modifying system for stimuli-responsive functional finishing of cotton

An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as chitosan, results in a microgel that is responsive to both temperature and pH, the microparticulate hydrogel of poly-NiPAAmchitosan copolymer (PNCS) was synthesized using surfactant-free emulsion method. The microparticle size in dry (collapsed) state is estimated at 200nm by SEM and TEM, and effect of temperature and pH on microparticles was investigated by DLS and UV–vis spectrophotometry. The incorporation of PNCS microparticles to cotton material was done by a simple pad-dry-cure procedure from aqueous microparticle dispersion that contained 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli-responsiveness of modified cotton fabric has been confirmed in terms of regulating its water uptake in dependence of pH and temperature

Attachment of β-Cyclodextrins on Cotton and Influence of β-Cyclodextrin on Ester Formation with BTCA on Cotton

Cotton was treated with β-cyclodextrin (BCD) and two derivatives of β-cyclodextrin (2-hydroxypropyl-β-cyclodextrin and monochlorotriazinyl-B-cyclodextrin) to assess the optimal type for fixation with cotton. The experimental results showed that treatment of cotton with BCD using the crosslinker BTCA resulted in higher fixation than the treatments with the other two derivatives. The concentration of BTCA used did not significantly influuence the amount of fixation of BCD on cotton. FTIR-ATR spectroscopic analysis showed that the amount of ester formed on the fabric was influenced by the addition of BCD on cotton with BTCA in comparison to crosslinking of only BTCA with cotton. The laundering tests showed relatively poor washfastness of the β-cyclodextrins on the fabrics

Integrated approach to optimization of an ultrasonic processor

In an ultrasonic processor, the input electrical energy undergoes many transformations before getting converted into the cavitation energy, which is dissipated in the medium to bring out the physical/chemical change. An investigation of the influence of free and dissolved gas content of the system on the efficiency of this energy transformation chain is attempted. The results of the experiments reveal that the cavitation intensity produced in the medium varies significantly with the gas content of the system. A unified physical model, which combines basic theories of acoustics and bubble dynamics, has been used to explain the experimental results. An attempt has been made to establish the mechanism of the steps in the energy transformation chain, the involved physical parameters, and interrelations between them. It has been found that the influence of free and dissolved gas content of the medium on the overall energy transformation occurs through a complex inter-dependence of several parameters. Thus, simultaneous optimization of individual steps in the energy transformation chain, with an integrated approach, is necessary for the optimization of an ultrasonic processor. The present study puts forth a simple methodology, with the gas content of the system as manipulation parameter, for this purpose

Acoustical characteristics of textile materials

An attempt is made to identify the acoustical characteristics of textile materials using precision woven monofilament fabrics as model textiles. The experiments try to eliminate the effect of entrapped air pockets in the fabric on an ultrasound wave field. The results of the experiment reveal that the power consumption of the ultrasound horn remains practically constant after introducing the textile at different positions in the standing wave field. Measurements of transmitted acoustic pressure amplitude through the textile reveal that fabrics form an almost transparent boundary for acoustic waves. A simple model involving the structural and hydrodynamic characteristics of the textiles is proposed to determine their acoustic impedance, and the results of the experiments are explained on the basis of this model. The overall conclusion of the study is that in the absence of entrapped air, textiles do not have any individual impact on the ultrasound wave field. \ud \u

Applications of B-cyclodextrins in textiles

In this paper, the general features of β-cyclodextrin and their applications in the textile industry have been reviewed. The use of β-cyclodextrin in the textile industry is of great significance due to its wide range of application. One of the key aspects is the attachment technique of β-cyclodextrin to the textile's surface. This review deals with this in depth. Some quantification and characterization methods of Textile-β-cyclodextrin are discussed. In the last few years, the new direction in textile research is the functionalisation of textile systems. It is believed that β-cyclodextrin will play a very important role in these new developments. β-cyclodextrin can act as a host for various guest molecules. This enables the development of fabrics that release chemical compounds such as fragrances and antimicrobial agents. It is concluded that there are many possibilities for the development of new textile products with advanced properties based on β-cyclodextrin

Mechanism of mass-transfer enhancement in textiles by ultrasound

The intensification of wet textile processes, such as cleaning and dyeing, by application of ultrasound is well known. In these processes, mass transfer in the interyarn and intrayarn pores of the textile is the basic physical phenomenon. The results of experiments on textile cleaning, based on basic principles of acoustics and cavitation, coupled with analysis of the surface and cross section of the ultrasound-treated textile and high-speed imaging of the cleaning process, are reported. It is revealed that transient cavitation in the vicinity of the textile surface, and not the ultrasound wave itself, is the physical mechanism responsible for the enhanced cleaning effect. Intense microconvection due to the transient bubble motion driven by ultrasound enhances fluid flow and, thus, mass transfer through the textile

XPS and contact angle study of cotton surface oxidation by catalytic bleaching

Surface chemistry and wetting properties of cotton fibres as affected by catalytic bleaching have been investigated. Two types of cotton fabric have been analysed: the regular and a model cotton fabric. In the regular – double scoured cotton fabric, cellulose was contaminated with both non-removable and removable impurities including different pigments. The model cotton fabric, previously freed of most removable impurities, was stained for the purpose of this study with one pigment only, i.e. morin, a component that is typically found in native cotton fibre. Bleaching effectiveness of the catalyst based bleaches has been compared to the non-catalyst based bleaching systems. Surface chemical changes of cotton have been identified by XPS. Contact angle and capillary constant of the cotton fabric have been measured applying the Washburn method. This approach has provided the tool to explore and to quantify the chemical and physical effects on cotton fibre after catalytic bleaching. The interrelationship between an increase in capillary constant and the removal of non-cellulosic impurities, characterised by the C1 component in C 1s XPS spectrum, has been elucidated