Cotton fiber consumption is higher than any other natural fiber due to its superior mechanical and physical properties. In the conventional reactive dyeing process, the dye undergoes hydrolysis due to hydrogen bonding and weak Van der Waals forces, yielding poor washing color fastness. Additionally, the post-dyeing wash-off process consumes significant amounts of water, energy, and time in order to remove the unreacted and hydrolyzed dye. Therefore, reactive dyes are predominantly utilized to color cotton fabrics as the covalent bond formed between dye and fiber results in excellent washing fastness for a wide range of colors, and improved ease of use. To support more efficient, economical, and sustainable reactive dyeing, polymers can be used as effective dye transfer inhibitors (DTIs) in the reactive wash-off process. In this study, poly(vinylpyrrolidone) (PVP) homopolymer and poly(vinylpyrrolidone)-co-poly(vinylimidazole) (PVP-co-PVI) were synthesized at different molecular weights. These polymers were then employed as DTIs to evaluate their performance during the wash-off process for dyed cotton fabrics treated with three reactive dyes (Reactive Red 195, Reactive Blue 221, and Reactive Yellow 145). It is noteworthy to mention that the alternative wash-off procedure involved only three stages, in contrast to the series of washing steps necessary in the conventional method. Evaluation of the DTIs was focused on parameters such as color strength, washing fastness, chemical oxygen demand (COD), as well as energy, water, and time consumption. The findings revealed that while the polymer DTIs generated minor differences in dyed fabric colors in comparison to conventional dyeing, they significantly improved washing fastness. The polymer DTIs studied display excellent potential to provide a much more sustainable dyeing process by saving 90% energy, 40% water, and 50% time versus conventional wash-off processing. The wastewater COD values from the polymer-assisted reactive dye wash-off process were higher for all reactive dyes tested than those from conventional processing. While the higher COD values are attributed to the lower water volumes, this finding highlights the need for further studies. In summary, PVP polymers successfully served as DTIs in the reactive dyeing washing-off process, providing massive water-energy-time efficiency improvements and, subsequently, a more sustainable process for cotton fabric dyeing.

Photochemical degradation contributes to the environmental fate of many pesticides, chemicals, and industrial waste in surface waters. Photochemical degradation (PCD) of Nitrobenzene (NB) has been studied using a UV light source and Fenton reagent under different experimental conditions. The effect of concentration on PCD of NB was monitored and recorded in the range 0.5 x10-4M to 3.0x10-4M. The concentration of H2O2 was performed from 5.0 x10-4M to 2.5 x10-4M and Fe(II) from 1.0 x10-4M to 5.0 x10-4M respectively.In terms of concentration, the absorbance increases with increasing the concentration of the solution of NB, H2O2 and Fe(II). The initial rate of PCD was recorded at fixed pH 2.42 of solution. Two optimums for pH were found for PCD of Nitrobenzene ranging from pH 2.42 to 4.20. The intermediates formed during PCD of NB were identified, by which a mechanism was then suggested that PCD is actually found to follow pseudo first order kinetics.

Biopolymers and water-soluble nontoxic synthetic polymer composites using silver nanoparticles are astute approaches for antibacterial film fabrication. Moreover, surface treatment of the biopolymeric composite film by cold plasma can enhance the biocidal activity. Silver nanoparticles were synthesized by using the reduction method. Films were fabricated with different ratios of rice starch and polyvinylpyrrolidones (PVP) (1:0, 1:1, and 3:1), with and without silver (Ag) nanoparticles. A plasma jet was used to treat the film's surfaces by placing the Film 0.5 cm below the plasma discharge. Surface morphology was monitored by scanning electron microscopy (SEM), and the existence of Ag nanoparticles in the film was confirmed by X-ray diffraction (XRD). The UV-vis spectrum at 420 nm confirms Ag nanoparticles, which have an average hydrodynamic radius of 207.3 ± 21 nm, measured by a Zetasizer, and an average particle size of 69.85 ± 2.13 nm, analyzed by transmission electron microscopy (TEM). Moisture content, water absorption, swelling properties, tensile strength, contact angle, and DSC and TGA of all films were studied. It was observed that the moisture content, moisture absorption, and tensile strength increased after the addition of PVP, with few exceptions. All these properties were improved in plasma-treated films. Crystallinity, thermal stability, and glass transition temperature (T _g) were also enhanced when the surface of the films was treated with cold plasma. The antibacterial activity of these films was evaluated by using the agar diffusion method, and silver nanoparticle-containing films showed good antibacterial properties, which increased significantly after plasma jet treatment of the films. The findings indicated that the plasma surface-treated silver nanoparticle-incorporated rice starch-PVP composite film has the potential to be used as an antibacterial film. These films can be used as bandages for wound healing and antibacterial packaging.

Oxanorbornene cored 0.5, 1.5 and 2.5 generation ester terminated PAMAM dendronized monomers with 2 and 6 carbon-containing alkyl spacer in the middle of oxanorbornene core and dendronized branching were synthesized. Monomers were polymerized through the ring-opening metathesis polymerization (ROMP) technique by using 2nd and 3rd generation Grubbs catalysts to get dendronized ROMP polymers. It was found that Grubbs 3rd generation catalyst works well for 0.5 generation dendronized ROMP polymer whereas Grubbs 2nd generation catalyst works for the higher generation. We also found the linker effect during polymerization as six-carbon linker monomers polymerize with high yield along with higher generation. Finally, dendronized ROMP-based PAMAM encapsulated zero valent Cu nanoparticle was synthesized by using a reducing agent, NaBH₄. The catalytic activity of this nanoparticle was further investigated from the reduction of 4-nitrophenol to 4-aminophenol. Graphical abstract