Antibacterial functionalization of cotton and cotton/polyester fabrics applying hybrid coating of copper/chitosan nanocomposites loaded polymer blends via gamma irradiation.

In the present work, copper/chitosan nanocomposites (Cu/CS) were prepared in an aqueous solution in the presence of CS as stabilizer and CuSO4·5H2O precursor. The Cu/CS NPs formation was proved through transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier Transform infrared (FT-IR) spectroscopy and XRD diffraction. Cotton and cotton/polyester fabrics were gamma-radiation grafted by padding to pickup of 100%, in nanocomposites based on Cu/CS NPs loaded in polymer blends of poly(vinyl alcohol) (PVA) and plasticized starch (PLST). The grafted fabrics were characterized in terms of tensile mechanical, crease recovery and water absorption properties. The results showed that cotton fabrics displayed higher water absorption (%) than cotton/polyester fabrics for all PVA/PLST compositions and water absorption was found to decrease with increasing the ratio of PVA in the PVA/PLST blends. Cotton/polyester fabrics displays crease recovery angle (CRA) value of 147.6 upon treated with PVA/PLST (80/20%) and gamma irradiated to 30 kGy compared to CRA value of 125.0 for cotton fabrics treated under the same conditions. For cotton fabrics, the tensile strength was largely depends on the irradiation dose, in which the tensile strength of the treated fabric with the different formulations is higher than the untreated fabric. The antimicrobial activity of the fabrics against gram-positive bacteria (Staphylococcus aurous) and gram-negative bacteria (Escherichia coli) was investigated. In case of gram-positive bacteria cotton fabric showed the highest impact, for both 50/50 and 20/80 PVA/PLST of 14 and 14.5 mm inhibition zone, whilst, cotton/polyester fabric recorded 6 and 5 mm inhibition zone against gram-negative bacteria for 50/50 and 20/80 PVA/PLST, respectively.

Radiation synthesis and drug delivery properties of interpenetrating networks (IPNs) based on poly(vinyl alcohol)/ methylcellulose blend hydrogels.

Gamma radiation was used to prepare blend hydrogels from poly(vinyl alcohol) (PVA) and low ratios of methylcellulose (MC). The structure-property behavior was characterized by IR spectroscopy, gel fraction, differential scanning calorimetry (DSC) and swelling at room temperature and different pH values. The PVA/MC hydrogels were used as a carrier for doxycycline hyclate (DOX-h) drug. The results showed that the gel fraction of PVA/MC hydrogels decreased greatly with increasing the ratio of MC in the initial feeding solution. The PVA/MC hydrogels displayed pH-sensitive swelling character. The drug uptake-release study indicated that PVA/MC hydrogels possessed controlled release behavior and that the release process depends on pH. In this respect, the release of DOX-h drug was significant in alkaline medium.

Swelling and mechanical properties of superabsorbent hydrogels based on Tara gum/acrylic acid synthesized by gamma radiation.

The main objective is to develop a new superabsorbent system especially for using in diaper applications. In this study, hydrogels based on Tara gum/acrylic acid (TG/AAc) were prepared by gamma irradiation, in the presence of N,N'-methylenebisacrylamide (MBAAm) as a crosslinking agent. The polymeric networks formed were characterized by FT-IR and evaluated by swelling studies as a function of MBAAm concentration, temperature and nature of the swelling medium. The swelling kinetics of the hydrogels was studied in terms of the diffusion exponent "n". The results showed that the water diffusion into hydrogels is a non-Fickian type. Mechanical measurements (stress-strain) curves of hydrogels were evaluated to calculate the shear modulus values and the average molecular weight between crosslinks (Mc). Moreover, the absorption under load at 37°C of water and urea aqueous solutions (as a major component of urine) by TG/AAc hydrogels was determined.