IR spectroscopic study of hydration of cellulose acetates and polyvinyl acetate

Kalutskaya, E.P.; Gusev, S. A.

doi:10.1016/0032-3950(83)90463-x

Cited by 5 publications

(8 citation statements)

References 5 publications

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“…The further increase in PVA beyond 30.0 × 10 −5 mol dm −3 again leads to the decrease in the values of the rate constant. The break point in the curve for the rate constant versus PVA coincides with the change in aggregation behavior of PVA studied by other methods (Kalutskaya and Gusev, ; Nagarajan, ; Satokawa and Shikata, ).…”

Section: Resultssupporting

confidence: 80%

Studies on the Hydration Behavior of Polyvinyl Alcohol in Aqueous Solution: A Kinetic Approach through the Hydrolysis of Benzocaine

Rahman

Rafiquee

2019

J Surfact & Detergents

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The present work investigates the structural and dynamical features of Polyvinyl alcohol (PVA) and surfactant–PVA system through the change in the rate of hydrolysis of benzocaine. The UV–Vis spectra of benzocaine showed that the absorbance values at λmax (284 nm) increased with the increase in PVA. The rate of hydrolysis decreased in the dilute‐ and high‐concentration regions of PVA, whereas it remains unchanged in the mid‐concentration range of PVA, known as the polymer–polymer interaction region. These observations correspond to the structural changes in PVA with the increase in PVA concentration in aqueous solution. The aggregation behavior of PVA was further studied using transmission electron microscopy micrographs. The rate constant for the hydrolysis of benzocaine showed peaked behavior with the increase in [CTABr] in the CTABr‐PVA mixed system. The sodium dodecyl sulphate (SDS) molecules modify the PVA chains into a more compact form, and so, the hydration number around PVA is decreased. Consequently, the less hydrophilic benzocaine entangles with SDS‐PVA, whereas OH– ions aggregate into the aqueous pseudophase, resulting in a decrease in the rate of hydrolysis in the SDS–PVA mixed medium. The calculated value of binding constant increased with the increase in PVA in both CTABr‐PVA and SDS‐PVA mixed systems.

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Section: Resultssupporting

confidence: 80%

Studies on the Hydration Behavior of Polyvinyl Alcohol in Aqueous Solution: A Kinetic Approach through the Hydrolysis of Benzocaine

Rahman

Rafiquee

2019

J Surfact & Detergents

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“…According to them, the band attributed to the carbonyl stretching v(C=O), which is around 1,735-1,740 cm −1 , shifts gradually towards lower frequencies upon hydration. A similar phenomenon has also been reported by other researchers [19,20]. In actual applications, high resistance towards dimensional change upon changing temperature and relative humidity is essential to optical films.…”

Section: Introductionsupporting

confidence: 86%

“…For all ATR-FTIR measurements, the peak intensity for 50% humidity is almost at an intermediate value between those of 0% and 100% humidity. In cellulose esters, water molecules could form hydrogen bonds with the hydroxyl and the carbonyl groups [20,23]. Considering that CAP and CTA contain only a small amount of the hydroxyl group, hydrogen bonding between carbonyl groups and water molecules would mainly be responsible for the decrease in orientation birefringence upon hydration.…”

Section: Atr Spectramentioning

confidence: 99%

Effect of Moisture on the Orientation Birefringence of Cellulose Esters

et al. 2011

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Orientation birefringence and its wavelength dispersion are studied for hot-drawn films of cellulose esters such as cellulose triacetate (CTA), cellulose diacetate (CDA), and cellulose acetate propionate (CAP) exposed to three different humidities of environments. Hot-drawn CTA films show negative birefringence that decreases with increasing wavelength. On the other hand, CDA and CAP films show positive birefringence that increases with increasing wavelength, i.e., the so-called extraordinary wavelength dispersion of birefringence. Upon exposure to high humidity environment, the orientation birefringence of CDA and CAP decreases. The decrease is prominent for the samples containing a large amount of water. CTA, however, shows an increase in magnitude of its negative orientation birefringence with increasing moisture content. The results can be explained by the increase of the polarizability anisotropy perpendicular to the stretching direction in the cellulose esters. It is found from ATR-FTIR measurements that hydrogen bonds are formed between carbonyl groups of cellulose esters and water molecules. Considering that orientation birefringence of cellulose esters is determined mainly by ester groups, the formation of hydrogen bonds contributes to the polarizability anisotropy, thus affecting the orientation birefringence.

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Section: Clusterization Of Absorbed Watermentioning

confidence: 99%

“…For this purpose, of special interest are experimental data [30] on IR-spectra of water in CA in CTA films. The authors of this work [30], attribute great importance to local energetic bonds with ester groups. Nevertheless, the analysis of presented dependencies of optical density (D) of the main bands of IRabsorption of water on the value of P/Ps (25OC) indicates their compliance with Eq.…”

Section: Clusterization Of Absorbed Watermentioning

confidence: 99%

The Entropic Mechanism of Water Solvation of Polymers

Mikheev

Заиков

2000

International Journal of Polymeric Materials and Polymeric Biom

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Computational analysis of isotherms of equilibrium water absorption by polymers indicates the isotherms follow the theory of volume-centered filling of micropores regardless of the hydrophilicity of polymers. Structure of a microporous adsorbent, absent in the initial state, is formed through reorganization of chains of the molecular-chain sponge during adsorption. Thus, a part of chain units is combined in micropores isolating water molecules as clusters, and another part is redistributed around the clusters as a fringe that stabilizes the system by increasing the configuration entropy.The problem of the physical state of sorbed water in polymers is important from positions of the mechanisms of its diffusion in polymeric membranes, its effect on physical properties of polymers, participation in dyeing and fading of fabrics, superseding of stabilizers and plasticizers, and also in guided delivering of drugs in the organism from polymeric units of medical use.

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IR spectroscopic study of hydration of cellulose acetates and polyvinyl acetate

Cited by 5 publications

References 5 publications

Studies on the Hydration Behavior of Polyvinyl Alcohol in Aqueous Solution: A Kinetic Approach through the Hydrolysis of Benzocaine

Studies on the Hydration Behavior of Polyvinyl Alcohol in Aqueous Solution: A Kinetic Approach through the Hydrolysis of Benzocaine

Effect of Moisture on the Orientation Birefringence of Cellulose Esters

The Entropic Mechanism of Water Solvation of Polymers

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