Journal of Colloid Science最新文献

A model for diffusion in a glassy polymer 玻璃状聚合物中的扩散模型

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90071-1

W.R Vieth, K.J Sladek

{"title":"A model for diffusion in a glassy polymer","authors":"W.R Vieth, K.J Sladek","doi":"10.1016/0095-8522(65)90071-1","DOIUrl":"10.1016/0095-8522(65)90071-1","url":null,"abstract":"<div>A new technique for estimating diffusion rates in solid materials from transient sorption data was developed and applied to the diffusion of gases in polymer films. Specifically, the analysis developed here applies to solutes which are sorbed according to a particular isotherm: one described by a linear component (Henry's law) and a commonly observed nonlinear component (Langmuir equation). The linear component corresponds physically to gas dissolved in the amorphous regions of the polymer; the nonlinear, to gas trapped in polymer microvoids, analogous to the adherence of gas molecules to sites on the surface of porous adsorbents.By using this equilibrium isotherm together with the assumptions that the gas trapped in microvoids is immobilized, and that the driving force for diffusion is the concentration gradient of dissolved molecules, a mathematical description of transient sorption was developed; this diffusion model consisted of a nonlinear partial differential equation. With the use of a finite-difference technique, solutions to the equation were obtained; these were next applied to data for the solution of CO2 in a one mil “Mylar” polyester film at 40°C. The diffusivity was estimated to be 1.74 × 10−9 cm.2/sec. and the precision of the method was estimated at ±12%.In summary, the method developed has been successfully applied, and the proposed diffusion mechanism was thereby validated. It is believed that this method has wide potential applicability not only to the study of diffusion in polymers but also to the measurement of effective diffusivities of gases in porous catalysts.</div>","PeriodicalId":15437,"journal":{"name":"Journal of Colloid Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1965-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0095-8522(65)90071-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80594499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 289

Inorganic ion exchange membranes 无机离子交换膜

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90064-4

J.I Bregman, R.S Braman

引用次数: 28

Kinetics of water and salt transport in cellulose acetate reverse osmosis desalination membranes 醋酸纤维素反渗透脱盐膜中水盐运输动力学

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90072-3

Alan S Michaels, Harris J Bixler, Robert M Hodges Jr.

引用次数: 40

Properties of organic-water mixtures. IV. The effect of various salts on the miscibility gap of the glycerol triacetate-water system 有机-水混合物的性质。四、不同盐类对三乙酸甘油-水体系混相间隙的影响

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90070-X

Richard J Raridon, Kurt A Kraus

{"title":"Properties of organic-water mixtures. IV. The effect of various salts on the miscibility gap of the glycerol triacetate-water system","authors":"Richard J Raridon, Kurt A Kraus","doi":"10.1016/0095-8522(65)90070-X","DOIUrl":"10.1016/0095-8522(65)90070-X","url":null,"abstract":"<div>The effect of various salts on the miscibility gap of the glycerol triacetate (GTA)water system was examined at 25°C. Whereas addition of NaCl and KC1 reduces the mutual solubility of GTA and water, the addition of certain other salts, e.g., perchlorates, thiocyanates, iodides, bromides, salicylates, and zinc chloride, increases the mutual solubility of GTA and water to such an extent that complete miscibility may result.For the anions listed the “salting-in” effects are, in general, insensitive to the cation used or its charge. Plots of equivalents of salt required to produce miscibility vs. wt. percent GTA showed curves with maxima usually at about 40% GTA. Miscibility at the maximum required ca. 1 mole of perchlorate or salicylate ions per kilogram of solvent; for thiocyanates, iodides, bromides, and zinc chloride, the corresponding concentrations were usually larger.For several salts measurements were made in the temperature range 2° to 75°C. The mutual solubility of GTA and water in the absence of salts increases slightly with increasing temperature. Less NaC7H5O3 was required for miscibility at a higher temperature. However, for Mg(ClO4)2, KCNS, NaI, and CdBr2, more salt was required for miscibility at a higher temperature.</div>","PeriodicalId":15437,"journal":{"name":"Journal of Colloid Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1965-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0095-8522(65)90070-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88026773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Transmission of water and ions through crosslinked hydrophilic membranes 水和离子通过交联亲水性膜的传输

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90073-5

R.F Baddour, D.J Graves, W.R Vieth

{"title":"Transmission of water and ions through crosslinked hydrophilic membranes","authors":"R.F Baddour, D.J Graves, W.R Vieth","doi":"10.1016/0095-8522(65)90073-5","DOIUrl":"10.1016/0095-8522(65)90073-5","url":null,"abstract":"<div>In order to develop better semipermeable membranes for reverse osmosis, the mechanism of water transport must be determined. An evaluation of existing theories led to the hypothesis that degree of crosslinking and polar group content of a polymer were important factors in determining its semipermeability.This hypothesis was tested by preparing a series of crosslinked reinforced mem branes by polymerization in a thin film between two plates. These membranes were copolymers of ethylene glycol monomethacrylate (EGM), ethyl methacrylate (EM), and ethylene glycol dimethacrylate (EGD). High-pressure reverse osmosis experiments with a sodium chloride solution and water sorption tests were then conducted and the results were correlated with the degree of crosslinking and hydroxyl content of the membranes.For copolymers of EGM and EGD, the degree of salt rejection rose as the membrane was more tightly crosslinked, then dropped off sharply. The rise was attributed to a decrease in translational motion of the polymer chain segments relative to one another, with associated hindrance to ion diffusion. The fall was due to monomersolvent incompatibility during polymerization with attendant precipitation of the polymer forming under these conditions, resulting in macrovoids in the membrane structure. As a result, water flux increased as the membrane was more highly crosslinked. Crosslinking had a great effect on water sorption.Copolymers containing EM showed virtually none of the semipermeability of EGM polymers. Water flux dropped off very rapidly, and salt rejection was not measurable. Perhaps most striking was the fact that water sorption tests showed a direct proportionality between hydroxyl content of the polymer and water sorption capacity.</div>","PeriodicalId":15437,"journal":{"name":"Journal of Colloid Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1965-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0095-8522(65)90073-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81530039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Editors' note 编者注

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90063-2

Milton Kerker, A.C Zettlemoyer

引用次数: 0

The permeation of lipid substances through porous membranes 脂质物质通过多孔膜的渗透

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90065-6

Charles W Carr

引用次数: 1

A theory of active transport 主动运输理论

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90067-X

Richard Conley La Force

引用次数: 1

A physical interpretation of the ionic fluxes in excitable membranes 可激膜中离子通量的物理解释

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90066-8

Martin Blank

{"title":"A physical interpretation of the ionic fluxes in excitable membranes","authors":"Martin Blank","doi":"10.1016/0095-8522(65)90066-8","DOIUrl":"10.1016/0095-8522(65)90066-8","url":null,"abstract":"<div>A mechanism is proposed for the ionic fluxes in excitable membranes based on recent studies of monolayer permeation and of interfacial ionic transport. The excitable membrane is assumed to be a homogeneous lipid bilayer with anionic groups on the inner and outer surfaces and nonselectively adsorbed cations at these sites. The bound ions are in high concentration at the membrane surface and they cause the enhanced ionic fluxes when released during activity. The free ions, which are in equilibrium with the adsorbed ions, give rise to the resting ionic fluxes. Starting with the steady state ionic concentration gradients, the current due to “depolarizing electrodes” causes the concentration of potassium ions near the outer surface to increase, and it is assumed that these ions exchange with and release the bound sodium ions. Because of the increased sodium concentration at the membrane surface, there is an increased sodium ion flux across the membrane. This flux causes a release and a reverse flux of potassium ions by a similar process. The fluxes have been calculated in terms of several membrane parameters, and they can account qualitatively for the ion fluxes and permeability ratios at rest and during activity, the actions of some ions and pharmacologic agents, the effects of ion depletion, etc. Therefore, the mechanism provides a basis for explaining the ionic events at excitable membranes in terms of physical processes at the membrane level.</div>","PeriodicalId":15437,"journal":{"name":"Journal of Colloid Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1965-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0095-8522(65)90066-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16914017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Dynamics of water transport in swelling membranes 水在膨胀膜中的运输动力学

Journal of Colloid Science Pub Date : 1965-12-01 DOI: 10.1016/0095-8522(65)90068-1

I Fatt, Thomas K Goldstick

引用次数: 83