C Maltesh - Academia.edu (original) (raw)

Papers by C Maltesh

Research paper thumbnail of Effect of Solids Concentration on Polymer Adsorption and Conformation

Water Soluble Polymers

The effect of solids concentration on the adsorption and conformation of polymers at solid/liquid... more The effect of solids concentration on the adsorption and conformation of polymers at solid/liquid interface was investigated using depletion adsorption and fluorescence techniques. The fluorescence of pyrene labeled polyethylene oxide at silica/water interface as a function of solids concentration revealed a surprisingly measurable change in polymer conformation as the solids content was increased. Adsorption density as well as coiling of the polymers was found to decrease with increase in solids concentration. These changes are correlated with the rheological behavior of the suspensions.

Research paper thumbnail of CHARACfERIZATION OF SURFACTANT AND POLYMER AGGREGATES AT mE CERAMIC SOLID. SOLUTION INTERFACE USING IN-SITU SPEcrROSCOPIC TECHNIQUES

There has been an increasing awareness recently of the value of applying the principles of surfac... more There has been an increasing awareness recently of the value of applying the principles of surface and colloid science to ceramics processing. Colloidal processing techniques offer greater control over mixing and packing density variations as compared to dry powder routes. Particles in a colloidal suspension can be dispersed through particle-particle repulsive forces resultinf from electrostatic interactio~ steric hindrance, or a combination of both. Such particle-particle repulsion helps assure both the breakup of the soft agglomerates held together by van der Waal's forces and the formation of . well-dispersed suspensions, even in multi-phase systems. Colloidal suspensions may be effectively used to eliminate unwanted flaw origins, such as hard agglomerates and particles larger than a certain size2. It has thus become the major objective of ceramic processing engineers to achieve a better control of the state of the dispersion of the powder processed and of the consequent susp...

Research paper thumbnail of Behavior of hydrophobically modified and synthetic water-soluble polymers in solution and in the presence of sodium dodecylsulfate

In surfactant-polymer flooding for enhanced oil recovery, polymer-surfactant interactions can aff... more In surfactant-polymer flooding for enhanced oil recovery, polymer-surfactant interactions can affect the feasibility of the process due to changes in interfacial tension, slug viscosity and reagent consumption due to precipitation and adsorption, the latter leading to wettability changes as well. Lower interfacial tensions extract more oil and polymer solutions of higher viscosity are more efficient in pumping out the slug. Surface activity and viscosity changes of some polymeric surfactants are investigated using techniques of fluorescence spectroscopy, viscometry and surface tension

Research paper thumbnail of Polymer-Surfactant Interactions: Effects of Ionic Strength, Polymer Charge & Binding Density on Surfactant/Polymer Aggregates

Surfactant science series, 1996

Research paper thumbnail of Fundamentals of oleic acid adsorption on phosphate flotation feed during anionic conditioning

Minerals and Metallurgical Processing

ABSTRACT

Research paper thumbnail of Interactions Between Pentadecylethoxylated Nonylphenol and Tetradecyltrimethylammonium Chloride Mixtures at the Alumina—Water Interface

ACS Symposium Series, 1996

Research paper thumbnail of Evidence of complexation between poly(acrylic acid) and sodium dodecyl sulfate

Colloids and Surfaces, 1992

... Binana-Limbele and Zana [3] studied interactions between SIDS and sodium poly(acrylute) (NaPA... more ... Binana-Limbele and Zana [3] studied interactions between SIDS and sodium poly(acrylute) (NaPAA) using fluorescence and conductivity measurements. ... The results are given in Fig. 3 for the case of PAA alone as well as in i1C pCCsGlll:i: iri a iliieii amount of SDS. ...

Research paper thumbnail of Flocculation of oxides using polyethylene oxide

Research paper thumbnail of Polymers as rheology modifiers

Colloids and Surfaces, 1992

Research paper thumbnail of Controlled Adsorption of Surfactant and Polymer-Surfactant Mixtures for Enhanced Separation/Beneficiation of Minerals

Mineral Processing and Extractive Metallurgy Review, 1992

Surface characteristics of solids are often comple:(due to changes during particle preparation as... more Surface characteristics of solids are often comple:(due to changes during particle preparation as well as inter.lctions with the surrounding environment. The key to their separation and bc:neliciation lies in manipulation of the surface chilra.:teri$tics by treatment with select~d reagent:;. Controlled adsorption or surf3ctants. polymers or 3 combination or both can modiry th~ urfaceofthemineraltoachievethedesird˜results.Alterationorsurfacepropertiesofphosphateoresandmt˜aloxidesusingurface of the mineral to achieve the desir~d results. Alteration or surface properties of phosphate ores and m~tal oxides using urfaceofthemineraltoachievethedesird˜results.Alterationorsurfacepropertiesofphosphateoresandmt˜aloxidesusinguch methods as adsorption and dissolution is discussed in this paper. Responses to these treatments are examinc:d using !1otation. dissolutif!n and t1uorescence s~ctroscopic techniques.

Research paper thumbnail of Effect of the degree of hydrolysis of polyacrylamide on its interactions with poly(ethylene oxide) and poly(vinylpyrrolidone)

Macromolecules, 1991

ABSTRACT

Research paper thumbnail of Aggregation behavior of and surface tension reduction by comblike amphiphilic polymers

Research paper thumbnail of Effect of binding of cations to polyethylene glycol on its interactions with sodium dodecyl sulfate

Langmuir, 1992

Interactions between polyethylene glycol and sodium dodecyl sulfate have been studied using fluor... more Interactions between polyethylene glycol and sodium dodecyl sulfate have been studied using fluorescence spectroscopy. Changes in polymer conformation on its association with the surfactant were monitored using polymers end-labeled with pyrene. The effect of various salts of sodium, cesium, lithium, and magnesium on the binding between polymer and surfactant was determined. The conformation of the polyethylene glycol is affected significantly by sodium dodecyl sulfate binding. Initial binding of the polyethylene glycol is affected significantly by sodium dodecyl sulfate binding. Initial binding of the surfactant causes the polymer to coil whereas saturation of the polymer by the surfactant causes the coiled polymer to stretch out. The amount of surfactant bound to the polymer depends on the cations in the solution as well as the affinity of the cation toward polyethylene glycol. The stronger the binding of the cation to polyethylene glycol the less is the interaction between sodium dodecyl sulfate and the polymer. 29 refs., 6 figs., 2 tabs.

Research paper thumbnail of Electrolyte Effects on the Surface Tension and Micellization of n -Dodecyl β- d -Maltoside Solutions

Research paper thumbnail of Visualizing Flocculation and Adsorption Processes in Papermaking Using Fluorescence Microscopy

Langmuir, 2000

... The sheets were then pulped in deionized water and mechanically refined (Canadian Standard Fr... more ... The sheets were then pulped in deionized water and mechanically refined (Canadian Standard Freeness 40 350−360 mL) using a ... We believe that the method and data presented in this paper are an important finding for papermaking and will ... (2) Smook, GA Handbook For Pulp ...

Research paper thumbnail of Stability of Graphite Suspensions in the Presence of an Amphiphilic Comb-Like Polymer

Journal of Dispersion Science and Technology, 1992

ABSTRACT

Research paper thumbnail of Adsorption of Cationic Flocculants to Paper Slurries

Journal of Colloid and Interface Science, 2002

Polymers of varying molecular weights and charges are extensively used for diverse papermaking op... more Polymers of varying molecular weights and charges are extensively used for diverse papermaking operations such as retention, drainage, and waste treatment/recovery. Owing to the heterogeneous nature of both the polymer and the paper slurry and to the high shear environment in which paper is made, it is a challenging task to study polymer adsorption in this system and, more importantly, to be able to correlate the results with paper machine performance. In this study, the technique of fluorescence microscopy was adapted to determine the adsorption characteristics of a fluorescent cationic flocculant on three different papermaking slurries. In the absence of fillers and dissolved and colloidal substances (DCS), polymer is shown to adsorb on high surface area regions of the fiber resulting from mechanical fiber processing operations. However, in a composite alkaline furnish containing CaCO 3 filler and under conditions and time scales prevalent on a papermachine, the polymer preferentially adsorbs to the filler. The filler flocs in turn are adsorbed to the fibrils. In a mechanical furnish with DCS, polymer-DCS complexes are formed that alter the adsorption characteristics of the polymer. Results are discussed in terms of kinetics of adsorption, shear-induced collisions, and interactions with solution species. Furthermore, the utility of the fluorescence microscopy technique to study adsorption in complex industrial matrices is demonstrated.

Research paper thumbnail of Size of the Sodium Dodecylsulfate Aggregate Bound to Polyethylene Glycol: Effect of Different Cations

Journal of Colloid and Interface Science, 1993

ABSTRACT

Research paper thumbnail of Adsorption ofn-Dodecyl-β-d-maltoside on Solids

Journal of Colloid and Interface Science, 1997

ABSTRACT

Research paper thumbnail of Binding of sodium dodecyl sulfate to polyethylene oxide at the silica—water interface

Journal of Colloid and Interface Science, 1992

... of 23,000 (polydispersity index 1.08 ) from Polymer Laboratories, Inc., UK, and sodium dodecy... more ... of 23,000 (polydispersity index 1.08 ) from Polymer Laboratories, Inc., UK, and sodium dodecyl sulfate ( 99 purity) from ICN Pharmaceuticals were used as received. Triply distilled water was used for all experiments. Methods For polymer adsorption tests, 0.4 g of silica was con ...

Research paper thumbnail of Effect of Solids Concentration on Polymer Adsorption and Conformation

Water Soluble Polymers

The effect of solids concentration on the adsorption and conformation of polymers at solid/liquid... more The effect of solids concentration on the adsorption and conformation of polymers at solid/liquid interface was investigated using depletion adsorption and fluorescence techniques. The fluorescence of pyrene labeled polyethylene oxide at silica/water interface as a function of solids concentration revealed a surprisingly measurable change in polymer conformation as the solids content was increased. Adsorption density as well as coiling of the polymers was found to decrease with increase in solids concentration. These changes are correlated with the rheological behavior of the suspensions.

Research paper thumbnail of CHARACfERIZATION OF SURFACTANT AND POLYMER AGGREGATES AT mE CERAMIC SOLID. SOLUTION INTERFACE USING IN-SITU SPEcrROSCOPIC TECHNIQUES

There has been an increasing awareness recently of the value of applying the principles of surfac... more There has been an increasing awareness recently of the value of applying the principles of surface and colloid science to ceramics processing. Colloidal processing techniques offer greater control over mixing and packing density variations as compared to dry powder routes. Particles in a colloidal suspension can be dispersed through particle-particle repulsive forces resultinf from electrostatic interactio~ steric hindrance, or a combination of both. Such particle-particle repulsion helps assure both the breakup of the soft agglomerates held together by van der Waal's forces and the formation of . well-dispersed suspensions, even in multi-phase systems. Colloidal suspensions may be effectively used to eliminate unwanted flaw origins, such as hard agglomerates and particles larger than a certain size2. It has thus become the major objective of ceramic processing engineers to achieve a better control of the state of the dispersion of the powder processed and of the consequent susp...

Research paper thumbnail of Behavior of hydrophobically modified and synthetic water-soluble polymers in solution and in the presence of sodium dodecylsulfate

In surfactant-polymer flooding for enhanced oil recovery, polymer-surfactant interactions can aff... more In surfactant-polymer flooding for enhanced oil recovery, polymer-surfactant interactions can affect the feasibility of the process due to changes in interfacial tension, slug viscosity and reagent consumption due to precipitation and adsorption, the latter leading to wettability changes as well. Lower interfacial tensions extract more oil and polymer solutions of higher viscosity are more efficient in pumping out the slug. Surface activity and viscosity changes of some polymeric surfactants are investigated using techniques of fluorescence spectroscopy, viscometry and surface tension

Research paper thumbnail of Polymer-Surfactant Interactions: Effects of Ionic Strength, Polymer Charge & Binding Density on Surfactant/Polymer Aggregates

Surfactant science series, 1996

Research paper thumbnail of Fundamentals of oleic acid adsorption on phosphate flotation feed during anionic conditioning

Minerals and Metallurgical Processing

ABSTRACT

Research paper thumbnail of Interactions Between Pentadecylethoxylated Nonylphenol and Tetradecyltrimethylammonium Chloride Mixtures at the Alumina—Water Interface

ACS Symposium Series, 1996

Research paper thumbnail of Evidence of complexation between poly(acrylic acid) and sodium dodecyl sulfate

Colloids and Surfaces, 1992

... Binana-Limbele and Zana [3] studied interactions between SIDS and sodium poly(acrylute) (NaPA... more ... Binana-Limbele and Zana [3] studied interactions between SIDS and sodium poly(acrylute) (NaPAA) using fluorescence and conductivity measurements. ... The results are given in Fig. 3 for the case of PAA alone as well as in i1C pCCsGlll:i: iri a iliieii amount of SDS. ...

Research paper thumbnail of Flocculation of oxides using polyethylene oxide

Research paper thumbnail of Polymers as rheology modifiers

Colloids and Surfaces, 1992

Research paper thumbnail of Controlled Adsorption of Surfactant and Polymer-Surfactant Mixtures for Enhanced Separation/Beneficiation of Minerals

Mineral Processing and Extractive Metallurgy Review, 1992

Surface characteristics of solids are often comple:(due to changes during particle preparation as... more Surface characteristics of solids are often comple:(due to changes during particle preparation as well as inter.lctions with the surrounding environment. The key to their separation and bc:neliciation lies in manipulation of the surface chilra.:teri$tics by treatment with select~d reagent:;. Controlled adsorption or surf3ctants. polymers or 3 combination or both can modiry th~ urfaceofthemineraltoachievethedesird˜results.Alterationorsurfacepropertiesofphosphateoresandmt˜aloxidesusingurface of the mineral to achieve the desir~d results. Alteration or surface properties of phosphate ores and m~tal oxides using urfaceofthemineraltoachievethedesird˜results.Alterationorsurfacepropertiesofphosphateoresandmt˜aloxidesusinguch methods as adsorption and dissolution is discussed in this paper. Responses to these treatments are examinc:d using !1otation. dissolutif!n and t1uorescence s~ctroscopic techniques.

Research paper thumbnail of Effect of the degree of hydrolysis of polyacrylamide on its interactions with poly(ethylene oxide) and poly(vinylpyrrolidone)

Macromolecules, 1991

ABSTRACT

Research paper thumbnail of Aggregation behavior of and surface tension reduction by comblike amphiphilic polymers

Research paper thumbnail of Effect of binding of cations to polyethylene glycol on its interactions with sodium dodecyl sulfate

Langmuir, 1992

Interactions between polyethylene glycol and sodium dodecyl sulfate have been studied using fluor... more Interactions between polyethylene glycol and sodium dodecyl sulfate have been studied using fluorescence spectroscopy. Changes in polymer conformation on its association with the surfactant were monitored using polymers end-labeled with pyrene. The effect of various salts of sodium, cesium, lithium, and magnesium on the binding between polymer and surfactant was determined. The conformation of the polyethylene glycol is affected significantly by sodium dodecyl sulfate binding. Initial binding of the polyethylene glycol is affected significantly by sodium dodecyl sulfate binding. Initial binding of the surfactant causes the polymer to coil whereas saturation of the polymer by the surfactant causes the coiled polymer to stretch out. The amount of surfactant bound to the polymer depends on the cations in the solution as well as the affinity of the cation toward polyethylene glycol. The stronger the binding of the cation to polyethylene glycol the less is the interaction between sodium dodecyl sulfate and the polymer. 29 refs., 6 figs., 2 tabs.

Research paper thumbnail of Electrolyte Effects on the Surface Tension and Micellization of n -Dodecyl β- d -Maltoside Solutions

Research paper thumbnail of Visualizing Flocculation and Adsorption Processes in Papermaking Using Fluorescence Microscopy

Langmuir, 2000

... The sheets were then pulped in deionized water and mechanically refined (Canadian Standard Fr... more ... The sheets were then pulped in deionized water and mechanically refined (Canadian Standard Freeness 40 350−360 mL) using a ... We believe that the method and data presented in this paper are an important finding for papermaking and will ... (2) Smook, GA Handbook For Pulp ...

Research paper thumbnail of Stability of Graphite Suspensions in the Presence of an Amphiphilic Comb-Like Polymer

Journal of Dispersion Science and Technology, 1992

ABSTRACT

Research paper thumbnail of Adsorption of Cationic Flocculants to Paper Slurries

Journal of Colloid and Interface Science, 2002

Polymers of varying molecular weights and charges are extensively used for diverse papermaking op... more Polymers of varying molecular weights and charges are extensively used for diverse papermaking operations such as retention, drainage, and waste treatment/recovery. Owing to the heterogeneous nature of both the polymer and the paper slurry and to the high shear environment in which paper is made, it is a challenging task to study polymer adsorption in this system and, more importantly, to be able to correlate the results with paper machine performance. In this study, the technique of fluorescence microscopy was adapted to determine the adsorption characteristics of a fluorescent cationic flocculant on three different papermaking slurries. In the absence of fillers and dissolved and colloidal substances (DCS), polymer is shown to adsorb on high surface area regions of the fiber resulting from mechanical fiber processing operations. However, in a composite alkaline furnish containing CaCO 3 filler and under conditions and time scales prevalent on a papermachine, the polymer preferentially adsorbs to the filler. The filler flocs in turn are adsorbed to the fibrils. In a mechanical furnish with DCS, polymer-DCS complexes are formed that alter the adsorption characteristics of the polymer. Results are discussed in terms of kinetics of adsorption, shear-induced collisions, and interactions with solution species. Furthermore, the utility of the fluorescence microscopy technique to study adsorption in complex industrial matrices is demonstrated.

Research paper thumbnail of Size of the Sodium Dodecylsulfate Aggregate Bound to Polyethylene Glycol: Effect of Different Cations

Journal of Colloid and Interface Science, 1993

ABSTRACT

Research paper thumbnail of Adsorption ofn-Dodecyl-β-d-maltoside on Solids

Journal of Colloid and Interface Science, 1997

ABSTRACT

Research paper thumbnail of Binding of sodium dodecyl sulfate to polyethylene oxide at the silica—water interface

Journal of Colloid and Interface Science, 1992

... of 23,000 (polydispersity index 1.08 ) from Polymer Laboratories, Inc., UK, and sodium dodecy... more ... of 23,000 (polydispersity index 1.08 ) from Polymer Laboratories, Inc., UK, and sodium dodecyl sulfate ( 99 purity) from ICN Pharmaceuticals were used as received. Triply distilled water was used for all experiments. Methods For polymer adsorption tests, 0.4 g of silica was con ...