Characterization of poly(vinyl alcohol)/gold nanocomposites obtained by in situ gamma‐irradiation method

Abstract

Gamma-irradiation induced reduction of gold (Au) ions was performed in aqueous poly(vinyl alcohol) (PVA) solution. PVA/Au nanocomposites with different contents of inorganic phase were prepared by solvent evaporation. The colloids and corresponding nanocomposites show visible light absorption with strong excitonic peak in the wavelength range from 520 to 550 nm. Morphological and structural characterizations of gold nanoparticles (Au NPs) and nanocomposites were performed by TEM, XRD, and FTIR measurements. Also, Mie and Maxwell-Garnett theories were applied to calculate optical properties of Au colloids and PVA/Au nanocomposites, respectively. The changes of heat resistance upon the increase of inorganic phase were correlated to the decrease in crystal perfection of polymer. Improvement of thermal stability of nanocomposites, compared with the neat PVA, was observed when the content of inorganic phase exceeds 1 wt %.

Polyvinyl alcohol–In2O3 nanocomposite films: synthesis, characterization and gas sensing properties

“…37,38 A broad endothermic peak, in the temperature range 325-420 K with its maxima around 373 K observed for pristine PVA as well as PVA-IO1 is attributed to removal of free (moisture) as well as hydrogen bonded water and corresponding relaxation of intermolecular hydrogen bonds between the hydroxyl groups of PVA. 39 The absence of any such peak (exotherm) in the thermograms recorded during the cooling cycle confirms this relaxation phenomenon associated with the removal of water molecules. The third endothermic peak in the DSC thermograms with peak temperatures around 496 K, 493 K and 461 K for pristine PVA, PVA-IO1 and PVA-IO5 samples, respectively, corresponds to the melting temperature (T m ) of PVA.…”

“…Consequently, heat resistance of the nanocomposite film also decreases, leading to lower melting temperatures. 39 The crystallinity of PVA in the nanocomposite films may also decrease because In 2 O 3 nanocrystals prevent the interactions between the main chain and the formation of hydrogen bonds (see FTIR discussion and Fig. 3b).…”

In vitro silver ion release kinetics from nanosilver/poly(vinyl alcohol) hydrogels synthesized by gamma irradiation

“…This, in turn, affected the chain mobility of PVA and also acted as physical crosslinks . In addition, the disappearance of the band positioned around 1592 cm −1 , which was the result of β‐diketone in residual vinyl acetate groups in partially hydrolyzed PVA, was probably the consequence of interaction with Ag nanoparticles. The band at 1141 cm −1 corresponded to a symmetric CC stretching mode in the ordered/crystalline regions of the PVA matrix.…”

Poly(vinyl alcohol) foams reinforced with carbon nanotubes for stapedial annular ligament applications

“…However, the elastic modulus of PVA foam is in range of 0.007–0.024 MPa which is much below the required values of 0.065–5.5 MPa for SAL . Consequently, various nanofillers like gold nanoparticle, graphene oxide (GO), and biocompatible fillers such as nanoscale cellulose fibers, natural rubber, and nanocellulose have been used to improve the mechanical properties of PVA foams. Carbon nanotubes (CNTs) due to their unique structural, remarkable mechanical properties, high surface area of 50–1315 m 2 g −3 ,and high aspect ratio of greater than 1000 has been tried as promising nanofillers material for reinforcement of PVA‐based nanocomposites .…”