In this work, Hydrogel nanocomposites were synthesized by solution polymerization of acrylic acid (AA) and itaconic acid (IA) in the presence of cotton fabric. Ammonium persulfate (APS) was used as the polymerization initiator in the presence of a crosslinker, methylene bisacrylamide (MBA). Insertion of Ag followed by reduction of Ag+ cations results in a Hydrogel nanocomposite. The structure and morphology of the resulting Ag nanoparticle-loaded grafted fabric was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Xray diffraction (XRD). The influence of both APS and MBA concentration on the swelling capacity of nanocomposites was also studied.

Hypothesis: Sensitizing the nanocomposite Hydrogel systems to multiple stimuli ensures increasing their efficiency from the viewpoint of the magnitude and rate of response of the system. Adding nanosilver to dual stimuli (pH and temperature) responsive chitosan/poly(vinyl alcohol)/nanoclay nanocomposite Hydrogel system increases the sensitivity of the chosen system to the third stimulus, i. e. the electric field, and enhances the overall rate of response of the system. Methods: The reduction of a silver salt to silver nanoparticles was performed by a green synthesis method within the nanocomposite Hydrogel system using chitosan as a reducing agent and poly(vinyl alcohol) as a stabilizer. Silver nanoparticle formation was investigated by UV-Vis spectroscopy. SEM was used to study the distribution of silver nanoparticles in the nanocomposite system. The structural characterization of nanocomposite Hydrogel was carried out by FTIR. Cyclic voltammetry was employed to evaluate the conductivity of the system. Findings: The peak observed at the wavelength of 410 nm confirmed the synthesis of nanosilver. The SEM micrograph showed the uniform distribution of nanosilver in the system. The results of the sensitivity of the responsive system to multiple stimuli indicated that the nanosilver increased the rate of response of the system in acidic and alkaline solutions. The maximum swelling rate of the system was at pH 2 and the temperature of 55° C, while the minimum rate was at pH 5 and the temperature of 20° C. The presence of nanosilver increased the rate of response of dual stimuli (pH and temperature) responsive system up to three times and its swelling rate to 1. 5 times. By applying an electric field at pH 2, the time of response of system decreased from hours to minutes and its swelling ratio increased up to 1. 7 times.

Films of chitosan/polyvinyl alcohol (PVA)/sepiolite nanocomposite were prepared by a simple and “green” route through solution mixing; followed by freezing–thawing cycles. The structures of nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis, X-ray diffractometry, and Fourier transform infrared spectroscopy. The SEM and TEM micrographs confirmed a needle-type dispersion of sepiolite nanoclay in the Hydrogel nanocomposites. The effects of sepiolite and chitosan/PVA weight ratio on the swelling of nanocomposites were investigated. The water absorbency of nanocomposites was decreased by introducing sepiolite nanoclay. The nanocomposites with high content of chitosan showed high swelling capacity. The nanocomposite films showed pH-dependent swelling behavior with a maximum water absorbency under acidic pH. The cefazolin with a broad-spectrum activity toward gram-positive and gram-negative bacteria was loaded in Hydrogels. The release of cefazolin from nanocomposites was evaluated at pH 7.4. The content of released drug was affected by both sepiolite amount and chitosan/PVA weight ratio. The nanocomposites films released more cefazolin than the neat Hydrogel film. Cefazolin-loaded nanocomposites showed the antibacterial activity with a large zone of inhibition against gram-positive Bacillus cereusbacterium.

In this study, removal of three toxic chemical pollutants, such as crystal violet (CV) dye, tetracycline (TC) drug, and phenol (PH) using sodium alginate-g-poly (acrylicacid-co-sodium, 4-ethenylbenzenesulfonate, hydrate)/Zinc oxide, and SA-g-poly(AC-co-EBS)/ZnO Hydrogel composite was prepared by co-polymerization method by addition of free radicals. The Hydrogel composite was characterized by TEM, FESEM, and XRD. Removal of laboratory sample aqueous pollutants (dyes, drugs, and phenol) using Hydrogel composite to give low absorbance (0.0001) utilizing UV-Vis spectrophotometer for at a chosen wavelength for 2 h. Comparative between ((SA-g-(PAAc-co-EBS)/ZnO, (SA-g-(PAAc-co-EBS), and ZnO NPs) surfaces as adsorbents. The best results of the percentage of removal (E%) of three pollutants arrange in order increasing (SA-g-(PAAC-co-EBS)/ZnO NPs > SA-g-(PAAC-co-EBS) > ZnO NPs), the good results of the percentage removal (E%) of Hydrogel composite, (92, 451%, 87.56%, and 82.56%) for CV, TC, and PH, respectively. Likewise, comparative between the amount of Zinc oxide nanoparticles (ZnO NPs) decorated of (SA-g-(PAAC-co-EBS) using (0.05, 0.08, 0.1, and 0.15 g). The good results of the percentage of removal (E%) of three pollutants about 0.1 g ZnO NPs. Re-cyclability and desorption studies indicated the best re-cycling performance of the prepared composite. Based on the results, the prepared Hydrogel composites can be useful as a promising, ecological, cost-effective, and efficient material for dyes decontamination. Studies was carry out using several desorption agents at concentration (0.01 N) like HNO3, NaOH, H3PO4, H2SO4, HCl, and water. The Hydrogel composite, was regeneration with 100% can be desorbed in diluted hydrochloric acid (0.01 N). The isotherm Freundlich and Langmuir models are also introduced, it has been found that all results follow the Freundlich model in the presence of three pollutants; this nonlinearity is higher when using the Freundlich model.

In this research, a novel generation of stoppers for in-service natural gas distribution and transportation pipelines was prepared on the basis of nanocomposite Hydrogels for preventing the gas leakage during the welding operation. The nanocomposite Hydrogel stoppers were prepared on the basis of polyvinyl alcohol as the matrix phase and montmorillonite nanoclay as the reinforcing phase. Some structural, physical and mechanical properties of the prepared stoppers were experimentally investigated and their dehydration kinetics and the stopping performances were also evaluated. The results showed that the nanocomposite Hydrogel stoppers possibly had an exfoliated morphology and the presence of montmorillonite in their structures increases the crosslinking and improves the mechanical properties (up to 280% increase in the elastic modulus and a 43% decrease in the elongation at break). The results obtained from the dehydration tests demonstrated that the weights of prepared stoppers are reduced to 60-70 % of their initial weights during the first hour of the dehydration process. The results obtained from the stopping performance showed that the prepared nanocomposite Hydrogel stoppers could undergo the gas pressure up to 9 psi. It was observed that the stopping ability and the maximum endurable pressure of the prepared nanocomposite Hydrogel stoppers are increased by increasing the diameter and length of the stopper. The accomplished experiments for investigating the stopping ability of the nanocomposite Hydrogel stoppers proved their unique performances in perfect sealing and preventing gas leakage in natural gas pipelines. In general, it can be expressed that the prepared nanocomposite Hydrogels are suitable candidates to be used as novel stoppers during the welding operation in the natural gas distribution and transportation pipelines.

Superabsorbent nanocomposite was synthesized via copolymerization of acrylic acid (AA) and polyethylene glycol (PEG) onto carrageenan. The copolymerization reaction was carried out in aqueous medium and in the presence of ammonium persulfate (APS) as initiator, N, N`-methylene bisacrylamid (MBA) as cross linker and montmorillonite (MMT) as nanoclay. The superabsorbent nanocomposite structure was confirmed by FT-IR spectroscopy and X-ray diffraction. The swelling behavior of superabsorbent nanocomposite was also investigated in distilled water and various salt solutions. Thermal properties of synthesized superabsorbent nanocomposite were studied by using thermal gravimetric analysis, differential thermal gravimeter and differential scanning calorimeter. It was observed that the high thermal resistance of nanocomposite Hydrogel and Hydrogel carrageenan is high.