Vinyl alcohol

About: Vinyl alcohol is a research topic. Over the lifetime, 13839 publications have been published within this topic receiving 315464 citations. The topic is also known as: Ethenol & Hydroxyethene.

Preparation and Characterization of Pol(vinyl Alcohol）/ Cellulose Nanocomposites

Abstract: In this study, nanocomposite membranes were prepared from poly (vinyl alcohol) (PVA) with different amounts of cellulose nanocrystals as filler and characterized by thermogravimetry (TG). Swelling sorption behavior of various feed alcohol mixtures was investigated at 80°C, and found that NCC in PVA matrix could help to reduce the overall membrane swelling. Mechanical properties of the nanocomposite membranes were examined in relation to NCC content in the composite. Optimal NCC content in the composite was found to be 3 wt% in terms of its overall properties as compared to neat PVA film. With the addition of 3 wt% NCC to PVOH the ultimate tensile strength showed improvement compared to pure PVA. The PVA/ NCC nanocomposite membrane had shown increases in elongation at low filler loadings. The TG analysis demonstrated that the nanocomposite membranes exhibited higher thermal resistance.

Fourier Transform Infrared Spectroscopic Investigation of the Electric-Field-Induced Reorientation of the Nematic 7CPB with Different Prealignment

Abstract: Time-resolved Fourier transform infrared (FT-IR) polarization spectroscopy was employed to study the electric-field-induced reorientation of nematic p-cyanophenyl-p-n-heptylbenzoate (7CPB) in the bulk of the cell and near (within 1 μm) the surface of the electrodes. The initial orientation of 7CPB on the germanium electrodes was varied in order to obtain information concerning the behavior of the liquid crystalline molecules in the boundary region. Model systems containing the 7CPB on rubbed polyimide and poly(vinyl alcohol), non-rubbed polyimide and poly(vinyl alcohol), and blank germanium were prepared and investigated.

Self-healing polymer–clay hybrids by facile complexation of a waterborne polymer with a clay

Abstract: Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay via mixing in an aqueous medium and subsequent casting. Without using chemical crosslinking agents or heat treatment, the poly(vinyl alcohol)–clay hybrid adhered strongly to substrates, showing self-healing when immersed in water (25 °C). The healing was completed within 1 min by soaking a damaged poly(vinyl alcohol)–clay film under such conditions as in cold water (2 °C), simulated seawater, steam, HCl solutions (pH = 1) and NaOH solutions (pH = 14). The healing was seen repeatedly 10 times.

Drug Amorphous Solid Dispersions Based on Poly(vinyl Alcohol): Evaluating the Effect of Poly(propylene Succinate) as Plasticizer.

Abstract: Although significant actions have been taken towards the utilization of poly(vinyl alcohol) (PVA) in the preparation of drug amorphous solid dispersions (ASDs) using fusion-based techniques (such as melt-quench cooling and hot-melt extrusion), several drawbacks regarding its rather high melting temperature and its thermal degradation profile make the use of the polymer extremely challenging. This is especially important when the active pharmaceutical ingredient (API) has a lower melting temperature (than PVA) or when it is thermally labile. In this vein, a previous study showed that newly synthesized polyester-based plasticizers may improve the processability and the thermal properties of PVA. However, the effects of such polyester-based plasticizers on the drug’s physicochemical and pharmaco-technical properties are yet unknown. Hence, the aim of the present study is to extend our previous findings and evaluate the use of poly(propylene succinate) (PPSu, i.e., the most promising plasticizer in regard to PVA) in the preparation of drug-loaded PVA-based ASDs. Dronedarone (DRN), a poorly water-soluble API, was selected as a model drug, and drug ASDs (using either neat PVA or PVA-PPSu) were prepared using the melt-mixing/quench cooling approach at low melting temperatures (i.e., 170 °C). DSC and pXRD analysis showed that a portion of the API remained crystalline in the ASDs prepared only with the use of neat PVA, while the samples having PPSu as a plasticizer were completely amorphous. Further evaluation with ATR-FTIR spectroscopy revealed the formation of significant intermolecular interactions between the API and the PVA-PPSu matrix, which could explain the system’s physical stability during storage. Finally, dissolution studies, conducted under nonsink conditions, revealed that the use of PVA-PPSu is able to maintain DRN’s sustained supersaturation for up to 8 h.

Fabrication of a sensitive electrochemical sensor based on modified screen printed electrode for hydrazine analysis in water samples

Abstract: One of the new electrochemical sensors to detect (N2H4) has been constructed on the basis of the screen printed electrode (SPE) modified with poly(vinyl alcohol)/chitosan/TiO2/chlorophyll nanocompo...