Azam Ali

Hydrophobic treatment of natural fibers and their composites—A review:

There is a growing interest in the development of natural fiber-reinforced composites, most likely due to their wide availability, low cost, environment friendliness, and sustainability. The market size for natural fiber-reinforced composites is projected to reach

Impact of hydrophobic treatment of jute on moisture regain and mechanical properties of composite material

5.83 billion by 2019, with a compound annual growth rate of 12.3%. The composite materials reinforced with wood, cotton, jute, flax or other natural fibers fall under this category. Meanwhile, some major factors limiting the large scale production of natural fiber composites include the tendency of natural fiber to absorb water, degradation by microorganisms and sunlight and ultimately low strength and service life. This paper has focused to review the different natural fiber treatments used to reduce the moisture absorption and fiber degradation. The effect of these treatments on the mechanical properties of these composites has also been summarized.

Electrical conductivity and physiological comfort of silver coated cotton fabrics

This study was aimed to investigate the effect of fluorocarbon, hydrocarbon, and hybrid fluorocarbon on the mechanical properties and moisture regain of jute fiber reinforced composite materials. A significant difference in moisture regain values of treated and untreated reinforcement samples was observed, when the concentration of chemical finish (hybrid fluorocarbs) was 40 g/L. The composite made from treated reinforcement regained very low moisture content as well as exhibited improved mechanical properties (tensile and flexural strength). Having both characteristics (hydrophilic and hydrophobic groups) in hybrid fluorocarbon, the treated jute fibers and corresponding composites showed better properties as compared to counterparts treated by other two chemicals, due to better interface.

Copper coated multifunctional cotton fabrics

Abstract The objective of present study was to develop multifunctional and wearable electrically conductive fabrics with acceptable comfort properties by in-situ deposition of silver particles. The effect of silver nitrate concentration and number of dips was investigated for change in electrical conductivity, EMI shielding, and antimicrobial properties of coated fabrics. The dynamic light scattering and SEM analysis were employed to study the morphology of deposited silver particles. The EMI shielding was found to increase with increase in concentration of silver particles. Later, the comfort and mechanical properties were studied. No significant decrease in air permeability and water vapor permeability was observed due to partial coverage of fabric pores by coating of silver particles. Moreover, the coated fabrics also showed promising behavior toward antimicrobial properties. When the durability of coated fabrics was examined against washing, the application of binder provided good retention of silver particles without loss of electrical conductivity of coated fabrics.

Wrinkle free plaited knitted fabrics without pre-heat setting

The present work deals with the development of electrically conductive cotton fabrics by in-situ deposition of copper particles. The dynamic light scattering, scanning electron microscope, and X-ray diffraction techniques were employed to study the morphology of deposited copper particles. The utility of conductive fabrics was analyzed for electromagnetic shielding ability over frequency range of 30 MHz to 1.5 GHz. The electromagnetic interference shielding was found to increase with increase in number of dips, which was attributed to increased reflection of EM waves due to dense, uniform, and percolated network of conductive copper particles on the surface. The sample produced from 100 and 150 dips exhibited the maximum shielding ability of 10 dB and 13 dB, respectively. Furthermore, the role of deposited copper particles on antibacterial properties was examined against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. The S. aureus showed more sensitivity towards copper particles as zone of inhibitions increased from 9.5 to 15.5 mm. At the end, the durability of fabrics was examined against washing after application of binder. The fabrics showed good retention of the copper particles, proved by scanning electron microscopic microstructures and small loss in the conductivity of the material after washing.

Comparative Performance of Copper and Silver Coated Stretchable Fabrics

Abstract Wrinkle free fabric at low cost is always a desirable aesthetic property. Different type of resins/finishes and pre-heat setting prior to processing are applied to avoid wrinkles in woven and hosiery, respectively. Current study is proposed to produce wrinkle free circular plaited knitted fabric by the elimination of a pre-boarding step. In this achievement, yarn covering parameters and compatibility of yarns with knitting machines are examined. Sock samples were analyzed for improved physical appearance (wrinkles) after various processes (pre-tumbling, dyeing, bleaching, and washing). Yarn specifications (sheath yarn fineness, sheath yarn texture i.e. shrink/un-shrink, covering air-knots) impact on socks physical appearance were also analyzed. The results clearly showed that by decreasing number of yarn covering air knots and sheath yarn fineness leads to prevention of wrinkle formation. The results also prove to be supportive for cost effectiveness by eliminating the pre-setting stage.

Investigation of Mechanical and Thermomechanical Properties of Nanocellulose Coated Jute/Green Epoxy Composites

The present work described the development of multifunctional, electrically conductive and durable fabrics by coating of silver and copper particles using a dipping-drying method. The particles were directly grown on fabric structure to form electrically conductive fibers. Particles were found to fill the spaces between the microfibers, and were stacked together to form networks with high electrical conductivity. The electrically conductive fabrics showed low resistance with high stretch ability. The utility of conductive fabrics was analyzed for electromagnetic shielding ability over frequency range of 30 MHz to 1.5 GHz. The EMI shielding was found to increase with increase in concentration of copper and silver particles. Furthermore, the heating performance of the copper and silver coated fabric was studied through measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. The maximum temperature (119°C for silver and 112°C for copper) were obtained when the applied voltage was 10 V. Moreover, the role of deposited particles on antibacterial properties was examined against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. At the end, the durability of coated fabrics was examined against several washing cycles. The fabrics showed good retention of the particles, proved by small loss in the conductivity of the material after washing.

Electrical Conductivity of PLA Films Reinforced With Carbon Nano Particles from Waste Acrylic Fibers

The present study was aimed to investigate the effect of nanocellulose coating on the mechanical and thermomechanical properties of jute/green epoxy composites. Cellulose was purified from waste jute fibers, converted to nanocellulose by acid hydrolysis and subsequently 3, 5 and 10 wt% of nanocellulose suspensions were coated over woven jute reinforcement. The composites were prepared by hand layup and compression molding technique. The surface topologies of treated jute fibers, jute cellulose nanofibrils (CNF), nanocellulose coated jute fabrics and fractured surfaces of composites were characterized by scanning electron microscopy (SEM). The prepared composites were evaluated for tensile, flexural, fatigue, fracture toughness and dynamic mechanical properties. The results revealed the improvement in tensile modulus, flexural strength, flexural modulus, fatigue life and fracture toughness of composites with the increase in concentration of nanocellulose coating over jute reinforcement except the decrease in tensile strength. Dynamic mechanical analysis (DMA) results also showed the increase in storage modulus and reduction in tangent delta peak height of nanocellulose coated jute composites.

Development of UV Protective, Superhydrophobic and Antibacterial Textiles Using ZnO and TiO2 Nanoparticles

The acrylic fibrous waste was effectively transformed into activated carbon through physical activation in single stage carbonization under charcoal using at different carbonization temperatures 800, 1000 and 1200 °C. The characterization of carbonized fibers was performed with the help of XRD and EDX in order to find out the degree of crystallinity and proportion of different elements in carbonized fibres prepared at different temperatures. Later on, the carbonized fibers were pulverized in dry conditions by high energy planetary ball milling to get activated carbon micro/nano particles. In addition to refinement of size, the electrical conductivity of pulverized carbon particles was found to increase with increase in milling time. Subsequently, the particles were incorporated into poly lactic acid (PLA) in different loadings from 1 to 10% to develop conductive green composite films. The composite films were then characterized for electrical, thermo-mechanical and thermal properties.

Superhydrophobicity, UV protection and oil/water separation properties of fly ash/Trimethoxy(octadecyl)silane coated cotton fabrics

In this research work, multifunctional cotton fabric comprising of UV protection, superhydrophobicity and antibacterial activity has been developed using facile pad-dry-cure method. In the first step, the concentration of repellent chemical has been optimized. Then, formulations containing nanoparticles of ZnO or TiO2 along with optimized concentration of repellent chemical and organic-inorganic binder have been applied to cotton fabric followed by the evaluation of functional properties. The surface morphology and elemental composition of treated fabric has been characterized through SEM and EDX, respectively. The treated samples have shown promising UV protection, superhydrophobicity and antibacterial properties durable upto 20 washing cycles.