Structural properties of γ‐irradiated poly(vinyl alcohol)/poly(ethylene glycol) polymer blends

Abstract

ABSTRACT:The effect of various doses of ␥ radiation on the structural properties of water-soluble polymer blends based on poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG) has been investigated. Although the aqueous solutions of individual PVA and PEG homopolymers were homogeneous and clear, films transparent to visual observation were only formed by solution casting of pure PVA and those blends containing low ratios of PEG up to 30%. The structure-property behavior of this range of blends before and after ␥ irradiation was investigated by light reflectance and UV absorbance, differential scanning calorimetry (DSC), IR spectroscopy, and tensile mechanical testing. The DSC thermograms of PVA/PEG blends, before or after ␥ irradiation, showed a solely endothermic peak over the temperature range 40 -140°C, which may have arisen from the melting of the PEG component or from the glass transition of PVA/PEG as a miscible blend in accordance with those calculated on the basis of the theoretical Fox equation. Also, these thermograms did not clearly show any transition that arised from the pure PVA component. However, the improvement in tensile mechanical properties of PVA/PEG blends, the reflectance, and the optical absorption measurements support the idea of improved miscibility after ␥ irradiation.

Chitosan‐based interpolymeric pH‐responsive hydrogels for in vitro drug release

“…However, ChVA1 seems to possess relatively higher extent of hydrogen bonding than the separate components of the blend. 26 The intensity of the OÀ ÀH band decreases upon irradiation of Ch/PVA blends up to 20 Kgy, compared with the nonirradiated films and inversely related to the irradiation dose, which is in good agreement with results in the literature. 26 This means that radicals are formed on the macromolecules resulted in self-crosslinking of PVA chains during irradiation and the extent of these effects depends mainly on the irradiation dose.…”

“…26 The intensity of the OÀ ÀH band decreases upon irradiation of Ch/PVA blends up to 20 Kgy, compared with the nonirradiated films and inversely related to the irradiation dose, which is in good agreement with results in the literature. 26 This means that radicals are formed on the macromolecules resulted in self-crosslinking of PVA chains during irradiation and the extent of these effects depends mainly on the irradiation dose. 27 It has been suggested that alkoxy radicals formed by g-irradiation of PVA decay mainly by formation of a-carbon radicals or by formation of an aldehyde and terminal alkyl radicals, which can readily converted into a-carbon radical.…”

Effect of Gamma irradiation on the nanofree volume and electrical properties of PVA/PEG/reduced graphene oxide nanocomposites

“…Also, it seemed that the irradiation increases the crystallinity since the intensity of the band around 1111 cm -1 which is correlated to the crystallinity has been increased and became sharper than the nonirradiated ones. This result is in good agreement with those of XRD pattern [3,32]. Fig.…”

“…Lifetime spectra for the samples of PVA/PEG doped with different amounts of RGO before and after exposure to 100 of γ-radiation have been analysed using LT program to obtain free volume 3 and I 3 3 is found to decrease from (1.849 to 1.645 ns) and from (1.862 to 1.776 ns) for nonirradiated and irradiated samples respectively with increasing the nanoscale RGO filler to the polymer matrix. Fig.…”

“…Over recent years, polymer nanocomposites have become the subject of extensive studies due to their promising novel properties compared to their individual components. Polymer blending and doping with nano-sized fillers will result in new nanocomposites with enhanced physical properties such as electrical and thermal conductivity, chemical stability, flexibility and easy processability [1][2][3][4][5]. Polyvinyl alcohol (PVA) is a semi-crystalline, water soluble and biodegradable polymer which has potential application owing to its stability and easy processability.…”