Pervaporative separation of a 1‐methoxy propanol and water mixture

Mandal, Sangita; Pangarkar, Vishwas G.

doi:10.1002/app.11183

Cited by 25 publications

(22 citation statements)

References 16 publications

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“…27,[30][31][32] The calculated degrees of crystallinity are listed in Table I. It was evident from the data that the degree of crystallinity of the samples increased with the concentration of the NaOH solution (see Fig.…”

Section: Resultsmentioning

confidence: 97%

Synthesis and characterization of novel, highly crystalline poly(vinyl alcohol) microspheres for chemoembolization therapy

Semenzim

Basso

Silva

et al. 2011

J of Applied Polymer Sci

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Biodegradable polymeric microspheres can be used to deliver drugs through controlled rate and targeted processes. The drug is released from the particles by drug leaching or degradation of the polymeric matrix. Crystallinity can play a very important role in the degradation of polymeric matrixes; it can affect the drug-release rate, especially in chemoembolization. Most commercial embolic agents have a low degree of crystallinity, and the correlation between the drug-delivery rate and the degree of crystallinity is not fully understood. This study presents the appropriated synthesis conditions for the preparation of highly crystalline poly(vinyl alcohol) and poly(vinyl alcohol)/poly(vinyl acetate) microspheres and physicochemical characterizations by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and cross-polarization/magic angle spinning nuclear magnetic resonance.

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Section: Resultsmentioning

confidence: 97%

Synthesis and characterization of novel, highly crystalline poly(vinyl alcohol) microspheres for chemoembolization therapy

Semenzim

Basso

Silva

et al. 2011

J of Applied Polymer Sci

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“…PVA is generally a semicrystalline polymer, and its crystallinity can be determined by DSC [38]. The degree of crystallinity of the PVA membranes in the present study was accordingly calculated from the DSC experiments using…”

Section: Bulk Structure Of Pva Membranesmentioning

confidence: 99%

Investigation on surface molecular conformations and pervaporation performance of the poly(vinyl alcohol) (PVA) membrane

Zhang

Wang

2009

Journal of Colloid and Interface Science

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“…It was noticed that in the dense polymeric membrane the gap among the chains provides the pathway of the permeates. However, the average inter-chain distance among the amorphous flexible chains is 0.4-0.5 nm and the van der Waals radius of water and ethanol molecules are 0.26 and 0.52 nm, 23 respectively. It would make more obstacles for ethanol than water.…”

Section: Resultsmentioning

confidence: 95%

Pervaporation of Ethanol/Water Mixtures Using Novel Hydrophobic Membranes Based on Concentrated Emulsion Polymerization

Shi

Zhang

et al. 2005

Polym J

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ABSTRACT:A pervaporation membrane was prepared via the concentrated emulsion polymerization method. The concentrated emulsion formed was pre-polymerized, after which a mixture of another hydrophobic monomer, a crosslinker and an initiator were added with stirring to the system. The gel formed was located between two glass plates and subjected to polymerization. The membrane copied the structure of its precursor concentrated emulsion and composed of closely packed latexes that squeezed each other. The micro-channel among the latexes provided additional pathways for the permeates. The morphologies of the concentrated emulsion and membrane were examined via optical and electron microscopies. The pervaporation performance of the membrane in the extraction of ethanol from ethanol/water mixtures was investigated. In certain ranges of composition, the flux and selectivity simultaneously increased. [DOI 10.1295/polymj.37.925] KEY WORDS Pervaporation Membrane / Ethanol / Concentrated Emulsion /The emphasis in this paper is on a new method to prepare pervaporation membranes. The prepared membranes will be used to pervaporate ethanol from ethanol/water mixtures. While the pervaporation of water from ethanol/water mixtures was investigated in a large numbers of papers, 1-6 the pervaporation of ethanol from such mixtures was examined in much fewer papers and is more difficult to achieve.Between ethanol and water, ethanol is more hydrophobic; for this reason, hydrophobic materials were naturally selected to pervaporate ethanol from ethanol/water mixtures.7-10 Most of the membranes were based on homopolymers or copolymers of siloxanes. However, polydimethylsiloxane membranes prepared using conventional methods, such as solvent casting and hot pressing, were dense membranes. Their total permeation rates were between 7 and 160 g/(m 2 Áh), with selectivity between 2.4 and 6.7 (30-37 C, 10 wt % ethanol in water), and an increase in selectivity was often associated with a decrease in the flux. 11,12Such performances are not satisfactory in applications.It was noticed that the polymeric membrane prepared via traditional methods are all dense ones, [13][14][15][16] in which the gap among the chains provides the pathway of the permeates. However, the average interchain distance among the amorphous flexible chains is 0.4-0.5 nm 17 and the van der Waals radius of ethanol molecules is 0.52 nm. For this reason, the interchain gap is not big enough for ethanol molecules to diffuse. In other words, the separation selectivity is not only controlled by the polarity, but also by the size of the molecule. For the purpose of preferably separation of ethanol from water, additional larger pathway for permeates should be provided. Among various preparation methods developed, concentrated emulsion polymerization constitutes the first choice.A series of hydrophilic/hydrophobic composite membranes was prepared via the concentrated emulsion polymerization method. 18,19 In a concentrated emulsion, the volume fraction of the dispersed phase is larger t...

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Pervaporative separation of a 1‐methoxy propanol and water mixture

Cited by 25 publications

References 16 publications

Synthesis and characterization of novel, highly crystalline poly(vinyl alcohol) microspheres for chemoembolization therapy

Synthesis and characterization of novel, highly crystalline poly(vinyl alcohol) microspheres for chemoembolization therapy

Investigation on surface molecular conformations and pervaporation performance of the poly(vinyl alcohol) (PVA) membrane

Pervaporation of Ethanol/Water Mixtures Using Novel Hydrophobic Membranes Based on Concentrated Emulsion Polymerization

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