Development of a nonaqueous solvent system for poly(vinyl alcohol) and its characterization

Abstract

Solubility of poly(vinyl alcohol) (PVA) in water prevents the preparation of various derivatives through homogeneous techniques as most of the derivatives thus formed are insoluble in aqueous medium. There are a number of solvents that can swell PVA under hot conditions but cannot dissolve PVA. In the present study, N,N-dimethyl acetamide (DMAc) has been identified as solvent in which PVA can be dissolved in the presence of an equimolar amount of lithium chloride (LiCl). 1 H nuclear magnetic resonance ( 1 H-NMR), 13 C-NMR, infrared (IR), and X-ray diffraction (XRD) studies have been carried out to characterize the regenerated poly(vinyl alcohol) (RPVA). DMAcLiCl is found to be a true solvent system for dissolution of PVA. An attempt has also been made to prepare poly(vinyl acetate) from this solution of PVA by a homogeneous technique.

Effect of Air Gap Distance on PES/PVA Hollow Fibre Membrane's Morphology and Performance

“…10 Nevertheless, lithium chloride (LiCl) has been noted to be able to solubilise PVA in DMAc solvent, with maximum solubility as high as 6.7 w/v% at 40°C as compared to DMSO which only exhibits swelling at the same temperature. 11 The incorporation of LiCl may induce an added benefit to the membrane's permeation as LiCl is also known to be a good pore former for membrane fabrication. 12,13 Based on the various reports collected, no definite conclusion could be made on the effect of air gaps on HF membrane morphology and performance spun with different formulations.…”

Surface properties of UV-irradiated poly(vinyl alcohol) films containing small amount of collagen

“…Due to solubility and biodegradability, PVA films are more and more common as packaging materials. Two technologies are used for PVA film production: casting from viscous water solution and/or blow extrusion from the melt [1][2][3]. Regardless of the method of PVA film preparation the surface of the film plays an important role in many applications.…”

Traitement et valorisation des sous-produits du bois. Application à l'élimination des colorants industriels

“…• la transformation des fonctions alcool primaire de la cellulose et de la lignine en fonction alcoolate (Schéma 1) ; • le greffage, selon la réaction ci-dessous [7,8], consiste à faire réagir l'alcoolate avec l'anhydride succinique dans la pyridine [9][10][11][12]. Le mélange est alors chauffé à reflux pendant des durées bien déter-minées.…”