No abstract

Superabsorbent hydrogels based on natural polymer, carboxymethyl cellulose (CMC)/ sodium alginate (SA) were prepared by 60 Co radiation as a source of initiation of crosslinking. The effect of different ratios of SA (20, 30, 40, and 50%) on the physical properties of the CMC/SA hydrogel such as gel fraction percentage (GF%), and swelling percentage (SW%) were investigated. It was found that the GF % decreases with increasing SA content in the hydrogel. While the SW% of CMC/SA hydrogel tends to increase with increasing SA content in the hydrogel at constant irradiation dose (2.5 kGy). Morphology of the hydrogels was examined using scanning electron microscopy, which indicates compatibility between CMC and SA. Thermal properties were also investigated using thermogravimetric analysis. It was found that the thermal properties of the hydrogel having different composition were almost the same. The results obtained from ultraviolet-visible spectrophotometric analysis show that the prepared hydrogels can be used in the removal of heavy metals from waste water. The ability to absorb these heavy metals is of great importance from the point of view of environmental pollution.

Superabsorbent hydrogels based on carboxymethyl cellulose and acrylic acid with clay montmorillonite (MMT) were synthesized using gamma irradiation. The effects of the radiation dose and MMT concentration on the physical properties such as gel fraction (%) and swelling behavior of the hydrogel were studied. Moreover, the morphological, structural, and thermal properties of the prepared hydrogels were characterized by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The swelling behavior of the as-prepared hydrogels in water, salt solutions, and different pH media was studied. The hydrogels showed higher swelling percentage in distilled water than in salt solutions. In addition, they exhibited higher swelling in basic medium rather than in acidic medium. Water retention (%) of these superabsorbent hydrogels decreased as the concentration of MMT increased in the hydrogel. The 1% MMT hydrogel could be considered as a water-managing material for agriculture and horticulture in desert and drought-prone areas. C

The graft copolymerization of acrylamide (AAm) monomer onto polyethylene-coated polypropylene (PE-co-PP) nonwoven fabric was carried out by the mutual irradiation method. The general peculiarities of the grafting have been studied by gravimetric, scanning electron microscope (SEM), mechanical properties, and Fourier transform infrared (FTIR) methods. The influence of absorbed dose, dose rate, as well as the monomer concentration on the degree of grafting has been determined. Metal ions uptake of Cu 2þ , Co 2þ , Ni 2þ by the grafted fabrics was evaluated.

In this work, poly(vinyl alcohol) (PVA)/clay hydrogel based on various ratios of clay (20%, 50%, and 60%) were prepared using freezing and thawing techniques followed by electron beam (EB) irradiation at different irradiation doses (20, 25, and 30 kGy). The physicochemical property of such hydrogel in terms of gel fraction (%) and water uptake (%) was investigated. The structure and property of the hydrogel were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM). Thermal property was investigated using differential scanning calorimetry and thermogravimetric analysis. The results indicated that the gel fraction (%) increases on increasing the clay content in the hydrogel at all irradiation doses. The results obtained by XRD and SEM show an intercalation and exfoliation between PVA and clay. The occurrence of one T g and T m of the hydrogel indicates the presence of complete miscibility between PVA and clay. Also, the prepared hydrogel exhibit high thermal stability by increasing clay content in the hydrogel. It was found that the prepared PVA/ clay hydrogel has a high water uptake, making it acceptable for the use in treatment of wastewater from heavy and toxic metal ions and dye wastes.