Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

A new approach to functionalize the surface of polyester textiles is described in this study. Functionalization was achieved by incorporating pH/temperature-responsive polyelectrolyte microgels into the textile surface layer using UV irradiation. The aim of functionalization was to regulate polyester wettability according to ambient conditions by imparting stimuli-responsiveness from the microgel to the textile itself. Microgels consisted of pH/thermo-responsive microparticles of poly(N-isopropylacrylamide-co-acrylic acid) either alone or complexed with the pH-responsive natural polysaccharide chitosan. Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, ζ-potential measurements, and topographical analysis were used for surface characterization. Wettability of polyester textiles was assessed by dynamic wetting, water vapor transfer, and moisture regain measurements. One of the main findings showed that the polyester surface was rendered pH-responsive, both in acidic and alkaline pH region, owing to the microgel incorporation. With a marked relaxation in their structure and an increase in their microporosity, the functionalized textiles exhibited higher water vapor transfer rates both at 20 and 40 °C, and 65% relative humidity compared with the reference polyester. Also, at 40 °C, i.e., above the microgel Lower Critical Solution Temperature, the functionalized polyester textiles had lower moisture regains than the reference. Finally, the type of the incorporated microgel affected significantly the polyester total absorption times, with an up to 300% increase in one case and an up to 80% decrease in another case. These findings are promising for the development of functional textile materials with possible applications in biotechnology, technical, and protective clothin

Intensification of mass transfer in wet textile processes by power ultrasound

In industrial textile pre-treatment and finishing processes, mass transfer and mass transport are often rate-limiting. As a result, these processes require a relatively long residence time, large amounts of water and chemicals, and are also energy-consuming. In most of these processes, diffusion and convection in the inter-yarn and intra-yarn pores of the fabric are the limiting mass transport mechanisms. Intensification of mass transport, preferentially in the intra yarn pores, is key to the improvement of the efficiency of wet textile processes. Power ultrasound is a promising technique for accelerating mass transport in textile materials. In this paper, the intensification of mass transfer in textiles under the influence of ultrasound on the basis of a total system approach is described. EMPA 101-test fabric was selected as a model for the cleaning process. This study focuses on two aspects, the mechanism of the ultrasound-assisted cleaning process and the effect of the presence of the cloth on the ultrasound wave field generated in a bath. It has been found that the dissolved gas content in the system plays a dominant role in the cleaning process. The cleaning effects observed are explained by two different mechanisms: small-amplitude acoustic bubble oscillations and micro-jets (resulting from the collapse of acoustic bubbles in the boundary layer between the fabric and the bulk fluid) that give rise to convective mass transfer in the intra-yarn pores. It has also been observed that the overall power consumption of the system varies with the position of the fabric in the acoustic field. This variation is explained on the basis of a model involving the specific flow resistance of the fabric and the physical properties of the standing waves

Functionalization of cotton with poly-NiPAAm/chitosan microgel: Part II. Stimuli-responsive liquid management properties

An innovative strategy for functional finishing of cotton involves application of stimuli-responsive surface modifying system based on temperature- and pH-responsive poly-NiPAAm/chitosan microgel. The stimuli-responsiveness implied to cotton is the consequence of swelling/collapse of the microgel particles incorporated to the fibre surface, which produces an active liquid management system. The performance of functionalized cotton fabric in terms of liquid management properties was assessed by choosing appropriate techniques (water uptake; thin-layer wicking; water retention capacity; and drying capability) and discussion of the results was based on the types of water that are expected to be present in hydrated cotton and stimuli-responsive microgel

Gas-liquid dispersing characteristics of turbine agitators

Applied Science

Role of mechanical action in low-temperature cotton scouring with F. solani pisi cutinase and pectate lyase

The two principal reasons that can hinder industrial success of bioscouring are the inability to remove cotton waxes at low-temperature and that bioscouring is a slow diffusion controlled process. The main objective of this paper is to develop an improved cotton scouring process by applying mechanical action and enzyme treatment to efficiently remove the cuticle and primary wall compounds from the cotton fibre. The role of the mechanical action for improving the bioscouring process is discussed. To study the effect, a known amount of mechanical energy was applied using the ‘wedge apparatus’ before and after the enzyme treatment. The effect of mechanical action was evaluated for a faster scouring process with cutinase, pectinase and optimum incubation conditions such as pH, temperature, ionic strength, enzyme concentration, and incubation time were determined.\ud \ud It is demonstrated that cutinase from fungus Fusarium solani pisi is effective in the degradation of cotton waxes at low-temperature in less than 30 min after applying mechanical action. Wax removal with cutinase reduces pectinase incubation time and increases hydrolytic rate of pectinase. By the introduction of mechanical energy a fast one-step low-temperature enzymatic cotton scouring process is developed at lab scale