Spectroscopic behavior of poly(vinyl alcohol) films with different molecular weights after UV irradiation, thermal annealing, and double treatment with UV irradiation and thermal annealing

El-Kader, K.M.A.

doi:10.1002/app.11743

Cited by 22 publications

(14 citation statements)

References 25 publications

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“…It was also observed that increasing PEG content into polymer blends increases the swelling ratios, and this is due to the increment in PVA hydrophilicity. In addition, it can be seen that the level of increase in swelling ratio (30,25,20, and 15 %) decreases with increasing PEG content (5, 10, 15, and 20 %). PEG is more hydrophilic than PVA so the swelling ratio increased with an increase in the molar ratio of hydrophilic groups of PEG component.…”

Section: Swelling Behavior and Gel Contentmentioning

confidence: 92%

“…The C = O bands were attributed to the carbonyl functional groups due to the residual acetate groups remaining after the manufacture of PVA from hydrolysis of poly (vinyl acetate) or oxidation during manufacturing and processing [24]. The values of C = O and/or C = C peak intensities indicate that PVA have the same resonating structure from alkene↔alkane and C = O↔C-Oand/or presence of hydrogen bond with oxygen of C = O group [25]. The absorption band at 1436 cm -1 is assigned as CH 2 bending vibration while the deformation vibration of C-CH 3 is associated with the absorption band at 1348 cm -1 .…”

Section: Fourier Transform Infra Red (Ftir) Spectroscopic Investigationmentioning

confidence: 99%

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Characterization of Electron Beam Irradiated Poly Vinyl Alcohol/Poly Ethylene Glycol Blends

Ali

Essa²

2013

J. Sci. Res.

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Poly vinyl alcohol (PVA) and poly ethylene glycol (PEG) blends were prepared and irradiated with different electron beam irradiation doses. The influence of the irradiation dose, and PEG content on the physico-chemical properties was investigated. The data regarding gel content demonstrated that the radiation-induced crosslinking of PVA and PVA/PEG samples increased as a result of increasing irradiation dose and decreasing PEG content. The swelling volume ratio shows an opposite behavior. The XRD parameters (crystllinity percent and d-spacing values) show a decreasing behavior for PVA and PVA/PEG blends as a result of either irradiation or blending PVA matrix with PEG. The DSC data illustrate a decreasing trend in melting point, glass transition temperature, and degree of crystallinity with increasing irradiation dose or PEG content. and unhydrolyzation properties, which makes it more environmentally friendly. In addition, PEG is more common which could reduce the cost of experiments and simplify the experiments process. PVA and PEG blends have been widely explored as water soluble polymers for numerous industrial, biomedical and pharmaceutical applications due to the advantages of nontoxic, non-carcinogenic and bioadhesive properties [8].The miscibility between the constituents of a polymer mixture is an important factor in the development of new materials based on polymeric blends. In miscible polymeric blends, there are often specific interactions between functional groups or polymer segments that lead to decrease of the Gibbs energy of mixing. Miscible polymer blends present only one phase, while immiscible blends present separated domains, and the final properties of polymer blends are directly related to the degree of their miscibilities [9]. In immiscible polymer blends, their physical properties are poor compared with those of parent polymers because of phase separations arising from weak interaction at the boundaries of component polymers. The miscibility and the physical properties of polymer blends can be improved by applying intermolecular interaction such as hydrogen bonding and dipole-dipole interaction between blend components. Intermolecular hydrogen bonding interaction by hydroxyl, halogen, carbonyl, and amide groups leads to the improvement of miscibility based on favorable enthalpic interaction between polymer chains. Addition of compatibilizer into immiscible polymer blends also improves the miscibility and the physical properties [6,[9][10][11][12]. For polymer-polymer miscibility investigations, the most useful techniques are electronic microscopy [13], spectroscopy [14], and thermal analysis [15]. Electron beam irradiation of polymer blends has been employed in improving the properties and miscibility of blends. High energy irradiation produces free radicals that can readily interact with each other forming crosslinking and strengthening the polymer structure. The objective of this study is to determine the effect of electron beam irradiation on the structural, physical and chemical propert...

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Section: Swelling Behavior and Gel Contentmentioning

confidence: 92%

Section: Fourier Transform Infra Red (Ftir) Spectroscopic Investigationmentioning

confidence: 99%

Characterization of Electron Beam Irradiated Poly Vinyl Alcohol/Poly Ethylene Glycol Blends

Ali

Essa²

2013

J. Sci. Res.

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“…PVA film practically does not absorb above 250 nm, which is obvious because of the very high hydrolysis degree of the rough polymer. Abd El Kader 44 reported that PVA samples in UV region, show two absorption bands at 284 and 327 nm, related to high energy absorption assigned as p-p* bonds (mainly C¼ ¼O and/or C¼ ¼C), which are present in the tail head of the polymer, and influenced by its molecular weight. The presence of cellulose in PVA matrix reduces the transmission capability of the polymer and this effect is influenced by the CNC content.…”

Section: Articlementioning

confidence: 99%

Cellulose nanocrystals extracted from okra fibers in PVA nanocomposites

Fortunati

Puglia

Monti

et al. 2012

J of Applied Polymer Sci

142

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Cellulose nanocrystals (CNC) were extracted from okra bahmia (Abelmoschus Esculentus) bast fibers and inserted in different tenors (1, 2, 5, and 10 wt %) as the reinforcement of a poly(vinyl alcohol) (PVA) matrix. The extraction of cellulose was carried out in a two-step procedure: the first chemical treatment led to the production of holocellulose by the gradual removal of lignin, while the subsequent sulphuric acid hydrolysis process allowed obtaining cellulose nanocrystals in an aqueous suspension. The dispersion of CNC in the composite appeared effective at low cellulose content (1 wt %), while it presented more problems for higher contents. However, a 5 wt % cellulose content proved ideal to promote a direct mechanical interaction between the PVA and cellulose structures. Thermal analysis demonstrated that the presence of okra did not have a large effect on glass transition temperature, while it sensibly modified the melting temperature of the PVA matrix, as well as the crystallization temperature, due to the nucleating action of the nanofillers. FTIR spectroscopy performed during the exposure to UV light underlined that no oxidative reactions occur after a short-time exposure and that a longer irradiation times are required to produce oxidation on neat matrix and PVA/CNC nanocomposites. The results confirmed that the presence of CNC does not affect the stability of the neat PVA matrix to the photodegradation after UV irradiation.

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“…The UV peak is a signature of the van Hove singularity in the graphene density of states [32]. The PVA only shows significant absorption for shorter wavelengths [33]. Fig.2a plots a typical Raman spectrum of an exfoliated flake on Si/SiO 2 .…”

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confidence: 99%

Sub 200 fs pulse generation from a graphene mode-locked fiber laser

Popa¹,

Sun²,

Torrisi³

et al. 2010

Applied Physics Letters

428

248

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Ultrafast fiber lasers with short pulses and broad bandwidth are in great demand for a variety of applications, such as spectroscopy, biomedical diagnosis and optical communications. In particular sub-200fs pulses are required for ultrafast spectroscopy with high temporal resolution. Graphene is an ideal ultra-wide-band saturable absorber. We report the generation of 174fs pulses from a graphene-based fiber laser.

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Spectroscopic behavior of poly(vinyl alcohol) films with different molecular weights after UV irradiation, thermal annealing, and double treatment with UV irradiation and thermal annealing

Cited by 22 publications

References 25 publications

Characterization of Electron Beam Irradiated Poly Vinyl Alcohol/Poly Ethylene Glycol Blends

Characterization of Electron Beam Irradiated Poly Vinyl Alcohol/Poly Ethylene Glycol Blends

Cellulose nanocrystals extracted from okra fibers in PVA nanocomposites

Sub 200 fs pulse generation from a graphene mode-locked fiber laser

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