Presence Of Nonionic Polymers Research Articles

Differential behavior of sodium laurylsulfate micelles in the presence of nonionic polymers

HypothesisTheory and practice have proven that the cleansing properties and irritation potential of surfactants can be controlled with the addition of co-surfactants or polymers. The size of the surfactant-polymer nanoassembly, which differs from the pure surfactant micelle, has been postulated to be the cause of the differences in a surfactant system’s ability to disrupt the skin barrier. However, a firm structure–function relationship connecting polymer and surfactant under a consumer relevant condition is yet to be established. It is therefore hypothesized that apart from the size, the shape and the chemical nature of the polymer might play crucial roles. ExperimentsWe used combined small-angle neutron scattering, nuclear magnetic resonance spectroscopy, tensiometry, and dye solubilization methods to investigate the shape, size, and intermolecular interactions involved in sodium laurylsulfate-based systems in the presence of two industrially important and chemically distinct polymers, polyethylene glycol and polyvinyl alcohol, adopting a consumer relevant protocol. FindingsApart from size, shape and inter-micellar interactions fine-tuned by the presence of the polymers are found to be the important factors. Secondly, the physicochemical property of the polymer including chemical structure, conformation, hydrophilicity, presence of side groups, all can have crucial influence on polymer-surfactant interaction, micelle formation, and micelle stability.

Chitosan as a potential stabilizing agent for titania nanoparticle dispersions for preparation of multifunctional cotton fabric

Titania (TiO2) nanoparticle dispersions in water were prepared using chitosan (CS) as the stabilizing agent. The dispersion stability was evaluated with respect to storage time, hydrodynamic particle size, and zeta potential. The effect of the molecular weight of CS and presence of non-ionic polymers (poly(vinyl alcohol) and poly(ethylene glycol)) as co-dispersants was investigated. Despite the increase in size of dispersed particles, the long-term storage stability of the dispersions improved with increasing concentration and molecular weight of CS. The TiO2/CS dispersions were applied on cotton fabric and characterized. The presence of CS did not seriously affect the photocatalytic self-cleaning activity (SCA) of TiO2; with CS, a SCA of 89% was achieved compared with a value of 96% without CS. In addition, the TiO2/CS-treated cotton fabrics provided UV protection and significant antimicrobial activity.

Colloidal behavior of aqueous montmorillonite suspensions in the presence of non-ionic polymer

In this paper we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of polyethylene oxide (PEO), then we were investigated the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non ionic polymer with molecular weight 6×103 g/mol. of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by X-rays diffraction also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel- Bulkley rheological model is used for the correlation of our experimental results.

Colloidal Behavior of Aqueous Montmorillonite Suspensions in the Presence of Non-ionic Polymer

In this paper, we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of PEO (polyethylene oxide). Then we are going to investigate the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non-ionic polymer with molecular weight 6x10 3 g/mol. of varying concentration mass (0.7%, 1%, 2% and 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by XRD (X-rays diffraction) also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand.

Analysis of the Interactions of Polyvinylpyrrolidone with Conventional Anionic and Dimeric Anionic Surfactant

Classical physical method has been applied in the present study of interaction between water soluble polymer with anionic dimeric and conventional anionic surfactants. Micellization activity of carboxylate-based anionic dimeric (CAD) as well as sodium dodecyl sulfate (SDS) surfactants in the presence of nonionic polymer, that is, polyvinylpyrrolidone (PVP), has been studied through conductometric and surface tensiometric measurements. From these methods the critical aggregation concentrations (CACs), critical micelle concentrations (CMCs), and the effective degree of counterion binding (β) were determined. For the evaluation of behavior of CAD toward the PVP various thermodynamic properties viz. standard Gibbs energy of micellization, standard enthalpy, and entropy of micellization of CAD/PVP mixed system have also been estimated and discussed. The results exhibit that anionic dimeric surfactant interacts strongly with PVP as compared to conventional surfactant.

Nucleation, growth and coalescence phenomena of air bubbles on quartz particles in different aqueous solutions

Understanding the generation and behaviour of air bubbles in the presence of different reagents is important in the solid/liquid separation processes used to treat mineral and water and wastewater by flocculation–flotation. The presence of large air bubbles in aerated flocs, which have higher up-rising rates, can lead to the development of higher capacity units. The present work evaluated the generation and behaviour of air bubbles on hydrophilic particles of quartz in water and other aqueous solutions (10 mg L−1 920SH non-ionic polymer, 30 mg L−1 DF250 surfactant and 50 mg L−1 Flotigan EDA amine). The operating parameters were the air bubble growth time, contact angle, adhesion, attachment and detachment. The main results showed that the air bubbles grew more readily in the presence of non-ionic polymers and after adhesion in non-ionic polymer and water. The formation of large bubbles in aerated flocs in an effort to develop industrial flocculation–flotation operations with higher throughputs units is di...

A conductometric investigation of hydroxypropylmethyl cellulose/sodium dodecyl sulfate/nonionic surfactant systems

Surfactant mixtures are very often used in various cosmetic and pharmaceutical products because they commonly act in synergism and provide more favorable properties than the single surfactants. At the same time, the 9 presence of polymers in mixtures of surfactants may lead to molecular interactions thereby affecting product stability and activity. For these reasons it is very important to determine the surfactant interactions influence on 1micellization and mixed micellization, as well as polymer-surfactants mixed micelles interactions. In this work we examined self-aggregation of nonionic surfactants, polysorbate 20 (Tween 20), polyoxyethylene octylphenyl ether (Triton X100) and polyoxyethylene-polyoxypropylene block copolymer (Pluronic F68) with ionic surfactant, sodium dodecylsulfate, in aqueous solution at 40?C using conductometric titration method. It was found that concentration region for mixed micelle formation depends on nonionic surfactant characteristics and its concentration. Formation of surfactants mixed micelles in the presence of nonionic polymer, hydroxypropylmethyl cellulose, and their binding to polymer hydrophobic sites, were investigated too. Analysis of obtained results points to different kinds of interactions in investigated systems, which are crucial for their application.

Investigations of flocculation possibilities of the water alumina suspension in the presence of nonionic polymer

The effect of solution pH and molecular weight of polyethylene glycol (PEG) and polyethylene oxide (PEO) on their adsorption as well as stability of the colloidal Al2O3 water suspension was studied. The following methods were applied: turbidimetry, spectrophotometry, viscosimetry, potentiometric titration and microelectrophoresis.It was shown that the increasing solution pH affects conformation of the adsorbed macromolecules which affects the stability properties of such systems. The polymer adsorption causes deterioration of the stability conditions of the investigated alumina systems in comparison to those without polymer at all investigated pH values. At pH 3 and 6 the effect of the suspension destabilization is significantly smaller than at pH 9. The most effective flocculent of Al2O3 water suspension is PEO of the molecular weight 218,000 at pH 9.

Comparative Study of Effect of Surfactant‐Polymer Interactions on Properties of Alkyl Polyglucosides and Alpha Olefin Sulphonate

AbstractThe properties of Alpha Olefin Sulphonate (AOS) and Alkyl polyglucosides (APG) were studied in the presence and absence of nonionic polymers such as polyethylene glycol, poly vinyl pyrrolidone and methyl cellulose and hydroxy propyl cellulose. Properties like surface tension, foaming, viscosity and emulsification were studied at a constant concentration of polymer (0.1%) and varying concentrations of surfactant. It was found that at low surfactant concentrations there is an association between surfactant and polymer at the liquid/air surface in the case of an anionic surfactant and a nonionic polymer, which is not seen in the case of nonionic surfactants and nonionic polymers. A nonionic polymer reduces the surface tension of AOS by forming a surfactant‐polymer complex which in turn increases the foamability, emulsifying property and viscosity of solution. APG does not show any effect on its surface tension in the presence of nonionic polymers but its foamability and emulsifying properties are improved. Reduction in surface tension is not the only reason behind increased foamability in the presence of the polymer. Higher molecular weight polymers give a rich, creamy foam because of increased viscosity in the surfactant solution as compared to lower molecular weight polymers.

Influence of nonionic polymers on the rheological and electrical properties of Egyptian bentonite

AbstractThe rheological properties of Egyptian bentonite suspensions in the presence of nonionic polymers were investigated. Two different types of nonionic polymers were studied: poly(ethylene glycol) (molecular weight = 6000 g/mol) and poly(vinyl pyrrolidone) (molecular weight = 40,000 g/mol). The rheological properties (plastic viscosity, apparent viscosity, and yield point) of concentrated clay suspensions (6–8% w/w) at different temperatures after 24 h were determined. As the nonionic polymer concentrations increased, the rheological properties of the bentonite suspensions showed a slight increase, especially at an 8% clay content. The electrical properties (electrophoretic mobility and ζ potential) of Egyptian bentonite in the presence of different nonionic polymers were measured with a ζ meter. The results showed that the ζ potential of this bentonite was higher with 200 mg/L poly (vinyl pyrrolidone) than with 1000 mg/L poly(ethylene glycol). Potential energy profiles for bentonite suspensions for these nonionic polymers were constructed to show that the net energy barrier for bentonite suspensions followed repulsion or attraction between particles. These profiles showed that the potential energy profile of a bentonite suspension with 200 mg/L poly(vinyl pyrrolidone) produced a high repulsion potential energy between clay surfaces; that is, the suspension stability improved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Influence of non-ionic polymers on the rheological behaviour of Na+-montmorillonite clay suspensions. Part II. Homopolymer ethyleneoxide and polypropylene oxide–polyethylene oxide ABA copolymers

The rheological behaviour of Na+-montmorillonite suspensions in the presence of non-ionic polymers has been systematically investigated. Two different series of non-ionic polymers were studied. The first consisted of ABA block copolymers of polyethylene oxide–polypropylene oxide–polyethylene oxide (PEO–PPO–PEO or PE series), of varying ethylene oxide chain length. The second was a linear polyethylene oxide polymer of different molecular weights (PEO series). Thus the role of the polymer structure and ethylene oxide chain length on the rheological behaviour of the clay suspensions was addressed. Adsorption measurements were made with the purpose of quantifying the amount of polymer adsorbed on the Na+-montmorillonite surface. Rheological properties of concentrated clay suspensions (3–6% w/w) were determined as the polymers gradually covered the clay particles. Flow curves were obtained from shear stress–shear rate measurements, and were fitted to the Herschel–Bulkley model. The viscoelastic properties of the suspensions were determined from dynamic oscillatory measurements. These results demonstrate that adsorption of non-ionic polymers on the Na+-montmorillonite particles led to a gradual stabilisation of the suspension. The stability was enhanced for a longer ethylene oxide chain length and was found to depend on polymer structure.

Micellar properties of aqueous solutions of hexadecyltrimethylammonium salts in the presence of nonionic polymer

Aqueous solutions of cetyltrimethylammonium surfactant molecules (CTAX; X - =Cl - , ClO 3 - , NO 3 - ) in the presence of nonionic polymer (poly(propylene oxide), MW=1000; poly(vinyl alcohol)-poly(vinyl acetate), MW=110 000) were investigated by means of photophysical techniques. The results presented give further evidence for the topology of a micell-polymer complex where a polymer chain is wrapped around several aggregates and only disturbs the hydrophobic outer part of the micelles by means of its penetrating segments. The presence of these segments induces the release of H 2 O molecules and causes a reduced counterion binding. Consequently, micelle-polymer complexes provide a more hydrophobic environment for solubilisates and are characterized by a lower micellar aggregation number

Effect of polymers on the stability of colloids flocculation of polystyrene latex by polyethers

The stability of a polystyrene latex in the presence of nonionic polymers and electrolytes has been studied by measuring the change in optical density of the latex with time. The relationship between flocculation rate and polymer concentration generally shows a characteristic maximum which shifts to lower polymer weight concentration with increasing molecular weight. The dependence of the flocculation rate curve on electrolyte concentration, and on the molecular weight and structure of the polymer, has been investigated, and the results are discussed in terms of a simple heterogeneous coagulation model.

Enhancement of enzymatic catalysis of cross-linked dextran in the presence of non-ionic polymer.

Die enzymatische Spaltung von vernetztem und gefarbtem Dextran mit Dextranase wird in Gegenwart von neutralem (nicht ionogenem) Polymer-Polyethyleneglykol erhoht.

Enzymatic reactions in the presence of non-ionic polymers.

Die enzymatische Spaltungsgeschwindigkeit von synthetischer hochmolekularer Stärke mitα-Amylase wird in Gegenwart von neutralen (nicht ionogenen) Polymeren erhöht. Die katalytische Wirkung hängt von der Konzentration des Polymeren und dessen Molekulargewicht ab. Die Zunahme derα-Amylase-Hemmung durch spezifischeα-Amylase-Antikörper in Gegenwart von neutralem Dextran wird nachgewiesen.