Amit Jadhav

Surface Deposition of Chitosan on Wool Substrate by Electrospraying

Electrospraying or electrohydrodynamic spraying is a technique of liquid atomisation by utilising electrical forces. In the electrospraying technique, the liquid at the outlet of a nozzle is subjected to an electrical shear stress by maintaining the nozzle at high electric potential. This produces a fine mist of extremely small and in some cases down to nanometer size droplets. The charge and size of the droplets can be controlled by adjusting the flow rate and voltage applied to the nozzle. Extending the scope of electrospraying, textile substrates can be coated with suitable polymer solution to enhance the surface functionalisation. This paper highlights the deposition of chitosan on wool subtrates using elctrospraying and its potential application in medical textiles.

The impact of super-absorbent materials on the thermo-physiological properties of textiles

The use of appropriate protective clothing systems in high-risk environments is absolutely essential. Such protective clothing may not provide the desired wearer comfort due to the complexities associated with the system. These constraints are largely due to the multiple layers involved in the protective ensemble. Firefighters’ protective clothing systems, in particular, have limited or no water vapor permeability. This prevents evaporative heat loss and leads to thermal strain and sweat accumulation. This accumulated sweat on the skin and on the internal layer close to the body causes considerable discomfort to the user due to the sensation of wetness. Extensive research has been done to improve the comfort properties of such protective clothing. This research adds yet another dimension where a new inner-layer construction has been developed with high liquid and vapor-absorption capacity that could assist in keeping the moisture and vapor away from the skin and, in addition, retain a dry microclimate close to the skin. The developed materials were tested for their biophysical properties that included tests such as thermal and water vapor resistance, air permeability and moisture management properties. Experimental results in this study indicated that super-absorbent materials, when incorporated into a woven textile material, showed enhanced wearer comfort. It was observed that these super-absorbent materials have the capability to quickly wick the moisture away from the body and, in doing so, have the tendency to keep the skin dry.

Towards sustainable and safe apparel cleaning methods: A review

Perchloroethylene (PERC) is a compound commonly used as a solvent in dry cleaning, despite its severe health and environmental impacts. In recent times chemicals such as hydrocarbons, GreenEarth(®), acetal and liquid carbon dioxide have emerged as less damaging substitutes for PERC, and an even more sustainable water-based wet cleaning process has been developed. We employed a systematic review approach to provide a comprehensive overview of the existing research evidence in the area of sustainable and safe apparel cleaning methods and care. Our review describes traditional professional dry cleaning methods, as well as those that utilise solvents other than PERC, and their ecological attributes. In addition, the new professional wet cleaning process is discussed. Finally, we address the health hazards of the various solvents used in dry cleaning and state-of-the-art solvent residue trace analysis techniques.

Study of Electrospraying Characteristics of Polymer Solution Coating on Textile Substrate

Electrospraying is a method of generating fine mist through electrostatic charging. It is a versatile method based on electrohydrodynamic process for forming small droplets. These droplets are highly charged. This prevents droplet coagulation and promotes self-dispersion which results in uniform coating on the target substrate. Electrospraying is inexpensive and an effective way to produce micro-scale coating. In this paper, an attempt was made to apply the electrospraying concept for coating textile surfaces. It was of interest to develop an understanding of the spraying characteristics of a polymer solution subjected to electrospraying and to determine the effect of the process parameters such as voltage, nozzle-collector distance and polymer concentration. Series of experiments were carried out employing different settings of process parameters. Thermoplastic polyurethane dissolved in tetrahydrofluran was used as a solution. The results provide some insight into selection of electrospraying parameters, and surface morphology of polymer deposition on fabric.

Influence of Applied Voltage on Droplet Size Distribution in Electrospraying of Thermoplastic Polyurethane

Textiles substrate coated with electrosprayed polymer droplets have a large specific surface area and sub micron range coating compared to commercial textiles, making them excellent candidates for use in medical and filtration applications. While the process of electrospraying is known for over half a century, current understanding of the process and the parameters that influence the properties of the polymer droplets produced from it is very limited. In this work, we have evaluated the influence of applied voltage on polymer droplet diameter. We find that applied voltage strongly affects the diameter of polymer droplet, and droplet diameter decreases with an increase in applied voltage.

Effect of Applied Voltage on Polymer Aggregation in Electrospraying of Thermoplastic Polymer

In an electrospraying process, the polymer solution interacts with the electric field. Charged polymeric solutions causing polymer liquids to move, break into drops or spray into fine droplets. Electrospraying has the ability to generate very small & uniform droplets of polymeric solution. It is envisaged that electrospraying is a promising technology to coat a polymer on surface at submicron range. The polymer aggregation is important while coating. The process parameters including applied voltage, nozzle-collector distance, solution flow rate, and solution concentration play an important role in polymer droplets aggregation on surface. This research paper investigates the effect of applied voltage on aggregation of polymer droplets.

Effect of Process Parameters on Jet Length in Electrospraying of Thermoplastic Polymer

Electrospraying is inexpensive and an effective way to produce submicron range coating. Spray Angle and Jet Length are important characteristics that affect coating quality while polymer solution subjected to electrospraying. It was of interest to determine the effect of the process parameters on Jet Length. In this paper, an attempt was made to apply the electrospraying concept for coating textile surfaces. Series of experiments were carried out employing different settings of process parameters such as voltage, nozzle-collector distance and polymer concentration. Thermoplastic polyurethane dissolved in tetrahydrofluran was used as a solution. The results provide some insight into the effect of electrospraying process parameters on Jet Length

Effect of Field Strength on Polymer Aggregation in Electrohydrodynamic Spraying of Thermoplastic Polyurethane

Polymer solution interacts with the electric field in an electrohydrodynamic (EHD) spraying process. Charged polymeric solution forces polymer liquids to move, break into spray of fine droplets. EHD spraying has the ability to generate very small & uniform droplets of polymeric solution. It is envisaged that EHD Spraying is a promising technology to coat a polymer on substrate at submicron range. The polymer aggregation is important while coating. The process parameters including applied voltage, nozzle-collector distance, solution flow rate, and solution concentration plays an important role in polymer droplets aggregation on surface. Field strength is also plays important role while EHD spraying. Field strength is the rate of change of potential with respect to distance. This research paper investigates the effect of field strength on aggregation of polymer droplets.

Thermal Comfort Characteristics of Knitted Fabrics for Abaya

Fabric material plays an important role in the thermal comfort of Abaya because it is the outer garment of Muslim women. Abaya is black in colour and covers the whole body except the hands, feet and face. It is mandatory to wear Abaya in the Saudi Arabia and certain parts of Middle East countries irrespective of the outside environmental temperature which could be up to 45°C. Therefore, the thermal transmission characteristics of the abaya are extremely important as human body responds to the external thermal environment through clothing. In a hot environment, it is extremely uncomfortable to wear several layers of clothing under the Abaya. Hence it is essential to enhance the thermal comfort of fabrics used for Abaya. This study investigated five selected knitted fabrics that could be used as Abaya fabrics for thermal resistance, air permeability, thermal comfort and vapour resistance. The results indicated that the fabrics with different knit structures, fibre composition and fabric weight have greater influence on thermal comfort performance.

Needleless Electrospinning and Electrospraying of Mixture of Polymer and Aerogel Particles on Textile

Needleless electrospinning and electrospraying of aerogel particles in comparatively lower electric voltage (9 kV) have been demonstrated in the paper. Aerogel particles were dispersed in polymer solution and then needlelessly electrospun/sprayed by creating high electric charge at the syringe tip using a curved wire. FTIR spectra and SEM images proved that aerogel particles were deposited onto the base textile. In case of electrospinning, a nanofibre web holding the aerogel particles covered the fabric surface, whereas in case of electrospraying, aerogel particles deposited with the microdroplets of the polymer. The electrospraying process showed great potential for fabric surface functionalization due to the high amount of particle deposition on fabric. The new approach can be applicable for transferring other particulate materials on fabric surface through needleless electrospinning and electrospraying processes.