Volume 42, Issue 2

The interactions of hardness ions (i. e., Ca, Mg, Ba) with anionic polymeric scale inhibitors (SI) containing different functional groups has been investigated using a turbidity technique. It has been found that all SI tested form insoluble salts with hardness ions under the experimental conditions used (pH 7.0 to 10.0, 25 to 65 °C, 100 to 1,000 mg/L Ca). The results indicate that compatibility of hardness ions with SI decreases with increasing pH, temperature, and hardness ion concentrations and increases with increasing NaCl concentrations. It has also been found that compatibility of hardness ion with SI can be improved by incorporating bulkier and hydrophobic monomer into SI structure. In addition, the data suggest that SI architecture (i. e., molecular weight, monomer functional group, and nature of polymerization solvents) influences the interactions of hardness ions with SI in aqueous systems.

This paper reappraises the dry cleaning process using compressed Carbon Dioxide as washing fluid, specifically in view to cleaning enhancement options. At first, the cleaning cycle of the process is presented. Thereafter, suitable surfactant classes are discussed against the background of prolific as well as an environmentally benign process. Among the most promising structures are the alcohol ethoxylates. Their physical properties such as solubility, phase behaviour, and interfacial activity were intensely studied. The performance of test-formulations in cleaning tests is promising and already suitable for outer garment cleaning. A new way of enhanced mechanical action was already demonstrated in a lab-scale apparatus.

The objective of this work was the analysis of dynamic wetting behaviour of aqueous surfactant solutions on polymer surfaces in respect of spreading characteristics evaluation. Surfactants with different ionogeneity (ionics and non-ionics) in a wide concentration range were used in this study. The sessile drop method was used to measure the contact angle, base radius and height of a drop containing surfactant as functions of time. Five polymer surfaces of different surface free energy were well prepared and characterised for this study. The analysis of the time dependency of the drop base radius reveals that the long-term spreading behaviour for all surfactant solutions follows power law with exponent values much lower than 0.1 which agrees neither with the diffusion-controlled spreading nor with Tanner's law. On the basis of experimental results, we conclude that a transfer of surfactant molecules on the bare polymeric surface in front of the moving liquid takes place as described by Starov et al. The transfer time can be used as a spreading characteristic which decreases with increasing concentration as predicted by Starov et al.

This papers reports the results of studies on flocculation of kaolin suspension by anionic polyacrylamide (PAM-A) flocculants in the presence of surfactant. They were namely anionic Sodium Dodecyl Sulphate (SDS), cationic Cetyl Trimethyl Ammonium Bromide (CTAB) and a non-ionic surfactant of polyoxyethylenic ether with trade name Triton (TX 100). The adsorption of PAM-A for fresh kaolin as well as surfactant pretreatment kaolin corresponding to about 50% coverage on the surface. Pretreatment of kaolin with all three surfactants form bigger flocs with PAM-A. The highest settling rate is obtained by flocculation the SDS-pretreatment kaolin. The influence of simultaneous addition of PAM-A and surfactants from their mixtures on flocculation is dependent on the nature of mutual interaction of PAM-A and surfactant. Simultaneous addition of PAM-A with either SDS or TX 100 increases settling rate, whereas it decreases when added from its mixture with CTAB. On the other hand, the optimum dose of PAM-A and 0.2 g/kg SDS-pretreatment preconcentrate El-Tih Egyptian kaolin is applied. The flocculation product a kaolin concentrate of minimum TiO 2 content (0.27%) and the degree of whiteness (93.5) is obtained from TiO 2 content (1.52%) and the degree of whiteness (63) of the original.

This paper investigates the effects of counterion microenvironments on the phase properties of ionic surfactants. The results of different isomers of hydroxy naphthoic acids (x, y HNC) and the cationic surfactant hexadecyltrimethylammonium hydroxide (HTAOH) are included. Mixing 3,2 HNC, 2,1 HNC or 6,2 HNC with micellar solutions of HTAOH transforms the micellar microstructure into different morphologies depending on the counterion microenvironments. The vesicles at equal concentration ratio of 3,2 HNC/HTAOH and 2,1 HNC/HTAOH have been characterized by freeze fracture electron microscopy (FF-TEM) and small angle neutron scattering (SANS). 6,2 HNC/HTAOH system does not form a liquid crystalline phase (L α -phase) at and above the equal concentration ratio. With these systems the effects that the hydrophobic counterion microenvironments have on the aggregate microstructure, rheological behavior, Krafft temperature and other physiochemical properties are discussed.

Ten components of NaNSF were separated by thin layer chromatography (TLC) by using F254 silica gel plates as fixed phase and acidic alcohol solution as mobile phase. Adsorption of naphthalene sulphonate formaldehyde (NaNSF) on titania surface was studied through fundamental principles of surface physical chemistry, and the saturation adsorption of NaNSF was found to be much lower than that of dispersant in disperse dyes. This study is of reference significance to the investigation of mechanism of adsorption of dispersant on dyes, cement, and so on.