Vijay Baheti

Reinforcement of wet milled jute nano/micro particles in polyvinyl alcohol films

Textile industry generate significant amount of waste fibres in form of short lengths during mechanical processing. However these short fibres possess excellent properties suitable for many other applications. The objective of this work was to use them for the preparation of nanoparticles/nanofibres as fillers in biodegradable composite applications such as food packaging, agriculture mulch films, automotive plastics, etc. The present paper concerns with jute fibres as a source of nanocellulose for reinforcement of PVA mulch films. Jute fibres were first refined to micro/nanoscale particles in form of nanofibrillar cellulose (NFC) by high energy planetary ball milling process in dry and wet condition. Wet milling was observed more efficient than dry milling in terms of unimodality of size distribution with reduction in size below 500 nm after milling for 3 hours. Later the obtained particles were used as fillers in Poly vinyl alcohol (PVA) films and their reinforcement evaluated based on thermal properties. It was observed that glass transition temperature (Tg) of PVA films improved from 84.36 °C to 95.22 °C after addition of 5 % jute particles without affecting % crystallinity and melting temperature (Tm) of PVA. Dynamic mechanical analysis of composite films with 5 % jute particles showed higher value of 14×108 Pa for storage modulus in comparison to 9×108 Pa of neat composite film. The percolation effect was observed more above glass transition temperature which consequently resulted in improved transfer of stiffness from jute particles to PVA matrix above 50 °C. The percolation phenomena also explained the improvement in thermal stability by 10 °C for every increased loading of jute particles due to formation of hydrogen bonds with PVA matrix.

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

Novelties of 3-D woven composites and nanocomposites

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.

Optimized preparation of activated carbon nanoparticles from acrylic fibrous wastes

This research is aimed to investigate the mechanical behaviour of 3-D woven fabrics as compared to 2-D woven fabrics and subsequently to check its suitability for composite applications. Mechanical tests especially related to ballistic protection of these fabrics were carried out to see the effect of fabric structure on its mechanical properties. The tensile test showed higher strength for 3-D fabrics as compared to 2-D fabrics. Improvement in the breaking load and energy absorption of 3-D fabrics was also observed in the impact test. Furthermore, applicability of 2-D and 3-D glass woven fabrics for composites was also studied in this work. An exploratory work has been carried out in the field of three phase composite in which fly ash nanoparticles were incorporated in addition with glass fabrics while preparing composites. These fly ash nanoparticles were prepared by high-energy ball milling technique and its effects on mechanical properties of composites were observed. Three-point bending flexural test showed higher flexural strength and modulus of 3-D woven composite and addition of nanoparticles further enhanced the properties of composites. Impact test analysis revealed that the 3-D woven glass fabric/epoxy composites exhibit superior breaking load and total energy than those with 2-D plain woven fabric as reinforcement.

Influence of noncellulosic contents on nano scale refinement of waste jute fibers for reinforcement in polylactic acid films

In present study, activated carbon is prepared by controlled pyrolysis of acrylic fibrous waste under the layer of charcoal using physical activation in high temperature furnace. The main objective is to study the effect of four factors (i.e. final pyrolysis temperature, holding time at final temperature, heating rate per hour, and number of steps) on carbonization behavior of acrylic fibrous waste. The Box-Behnken design and response surface modeling was performed to get higher specific surface area and higher electrical conductivity. The development of porous morphology having higher surface area is found to increase with increase in pyrolysis temperature, increase in number of steps, decrease in holding time and decrease in heating rate till some optimum value. This behavior is attributed to gradual reaction of atmospheric oxygen with carbonized acrylic fibrous waste, which resulted into the opening of previously inaccessible pores through the removal of tars and disorganised carbon. Moreover, these four factors also found to have significant effect on the development of electrical conductivity of activated carbon. Later on, the carbonized acrylic fibrous waste was pulverized in dry conditions by high energy planetary ball milling to get activated carbon nanoparticles. In addition to refinement of size, the specific surface area and electrical conductivity of pulverized carbon particles was found to increase with increase in milling time. The activated carbon particles obtained after three hours of dry milling revealed the particle size of 521 nm, the electrical conductivity of 21.78 s/m for 0.5 wt % concentration of aqueous dispersion and the specific surface area of 432 m2/g.

Ball milling of jute fibre wastes to prepare nanocellulose

In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface.

Removal of methylene blue from aqueous media using activated carbon web

The objective of this work was to use the spinning waste in form of short fibres for the preparation of nano size fillers in nanocomposite applications. The present paper concerns with the jute fibres as the source to produce nanocellulose by high energy planetary ball milling process and its potential applications as fillers in biodegradable nanocomposite plastics used in automotives, packaging and agriculture applications. Influence of various milling conditions like nature of milling (i.e. dry or wet), milling time and ball size are studied on the particle size distribution and morphology of jute nanoparticles obtained. Wet milling in the deionised water resulted into particle size refinement below 500 nm with narrow size distribution after 3 hours of milling at the cost of small amount of contaminations introduced from milling media.

Electrical conductivity and physiological comfort of silver coated cotton fabrics

Abstract Activated carbon web is prepared by controlled pyrolysis of acrylic fibrous waste under the layer of charcoal using physical activation in high-temperature furnace. The carbonization was carried out at 1200 °C under different heating rate (i.e. 150 to 450 °C h−1) with different holding time (i.e. 0 to 60 min) to decide optimum pyrolysis parameters. The heating rate of 300 °C h−1 with no holding time revealed higher specific surface area of 280 m2 g−1. The prepared activated carbon web was later employed as adsorbent for removal of methylene blue from aqueous media. The effect of initial dye concentration, adsorbent dosage, stirring speed, and pH of solution was studied. The obtained results were later compared with adsorption isotherms (i.e. Langmuir and Freundlich). The Freundlich model was found to fit closely with results due to heterogeneous adsorption of dye molecules. Finally, virgin activated carbon and dye adsorbed activated carbon were tested for desorption behavior using differential scanning calorimetry and thermo gravimetric analysis. The significant reduction in desorption enthalpy from 172.46 to 52.43 J g−1 is attributed to less adsorption energies of dye molecules on the surface of activated carbon due to nonhomogeneous distribution of active sites.

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.

Development of flame retardant high loft polyester nonwovens

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.