The possibility of substitution of the conventional pentanol as cosurfactant by butyl lactate, on the preparation of O/W microemulsions in a system with SDS as anionic surfactant, is investigated. Whereas a narrow region of O/W microemulsion is described for the system with pentanol for a critical ratio 85/15 between water and SDS, butyl lactate leads to wider regions of solubility for different water/surfactant proportions, making easy the preparation of these microemulsions. Besides this advantage, being butyl lactate obtained from renewable resources and considered as a safe and biodegradable product, the microemulsions prepared with this cosurfactant could be applied in technological fields as cosmetic and dermopharmaceutical, where the biological agressivity of pentanol could avoid any practical application. As a complementary study, the influence that 1,3-butyleneglycol as polar cosolvent exert on the microemulsion regions, was also considered. Although according to experimental data given in the paper 1,3-butyleneglycol affects only slightly the O/W region of microemulsions, it can be foreseen that its presence could provide emollient characteristics to the final compositions.

Abstract New possibilities on the substitution of pentanol as cosurfactant on the preparation of microemulsions with anionic surfactants, are suggested. Alternative systems with more skin compatible ingredients as are oleic acid and glycols, allows to obtain microemulsions of potential application in fields as are the cosmetic and dermopharmaceutical ones, in which the requirements of harmlessness of the ingredients reduces the possibility of application of the conventional microemulsions with pentanol. The capacities of solubilizing hydrocarbon, were stated depending on the chain lenght of the glycol as well as on the ratio of combination water/glycol. The possibilities of the different systems were evidenced by means of the corresponding phase diagrams, resulting that the shorter the hydrocarbon chain lenght of the glycol is (ethylenegtycol), the wider is the realm of microemulsion obtained, and being established an optimal ratio water/glycol around 1/1. Moreover, the system with oleic acid and ethylene...

The good application properties of the alkylpolyglucosides and the development of economical and efficient production processes have promoted an increasing usage of these surfactants. From the study of two ecological properties, biodegradability and toxicity, the environmental compatibility of these surfactants have been evaluated. Different alkylglucosides have been studied: pure n-alkylglucosides (C8C12) and commercial alkylgtutxeides oligomeric mixtures. Total biodegradation was studied on both Ready Biodegradability tests and Simulation tests. Toxicity tests were carried out on both Daphnia magna and luminiscent bacteria (Photobacteriram phasphoreum). Results obtained in the study on the ecological properties of alkylpolyglucosides allow to conclude the environmental acceptability of this new class of nonionic surfactants.

SynopsisThis paper attempts to systematize the preparation of cosmetic formulations by means of phase diagrams. The general criteria used to adapt the usually complex cosmetic systems to simple ternary diagrams W/O/S, consists of grouping the different ingredients according to their functional characteristics (hydrophilics, lipophilics and amphiphilics) that are located respectively in the corresponding vertices W, O and S. Thus, the polar ingredients are always incorporated simultaneously as a single phase, over the initial combinations O/S according to the classical titration procedure. Selective incorporation of the polar ingredients by means of the so‐called double‐titration procedures was studied. Independent consideration of the polar ingredients leads to modelling of the system in a regular tetrahedron in which the components are located at the four vertices. Several possibilities of double‐titration procedures are considered in the tetrahedron depending on the different sequences of incorporating the polar ingredients. The results obtained show a critical influence of the double‐titration procedures on two main aspects: limits of existence of the transparent gel realms, and rheological behaviour of some selected compositions. The different possibilities compared with the fixed characteristics obtained by the conventional method of preparation constitute an advantage in adapting a final formulation to the specific needs.

A comparative study of the potential toxicity and environmental impact of CrIII (CrCI3.6H2O) and CrVI (K2Cr2O7) salts was carried out. This evaluation was carried out on three biological substrates: a microcrustaceum (Daphnia magna), a luminiscent marine bacterium (Photobacterium phosphoreum) and a mixed bacterial population responsible of aerobic biodegradation processes. In the two first bioassays, direct toxic effects were measured while in the third, potential toxicity was determined through its inhibition effect on the biodegradation process of an anionic surfactant, sodium dodecyl sulphate. The results obtained show that the toxicity depends on the biological substrate used. Usually, CrIII salts are thought to have lower toxicity than CrVI salts. This study, however, has shown that, towards bacterial populations, CrIII salt is more toxic than the coresponding to CrVI salt. This may be due to pH changes induced by CrIII in aqueous solutions.

SynopsisFrequently, the incoporation of the polar phase, as a second step in the formulation of a cosmetic, is considered as a simple dilution process. This work shows the influence of the polar phase on the final formulation, according to its constitution as well as the method of incorporation. Modelling the system through a regular tetrahedron suggests alternative ways to the usual method of incorporation (direct titration with a polar phase with a given composition), based on selective incorporation of the polar ingredients (double titration procedures). Depending on the constitution of the polar phase, it is possible to obtain different kinds of formulations (gel, liquids, …), and, depending on the different possibilities of incorporation of the polar ingredients, identical compositions can be formulated in terms of percentage of their components, but showing different rheological characteristics, allowing an adaptation to the required specific needs of formulation.

Three ammonium halide type surfactants were tested under standard laboratory condition for biodegradability and acute toxicity to Daphnia magna and in the Microtox test with the luminescent bacterium Photobacterium phosphoreum. The tested compounds are dimethyldistearylammonium chloride (DSDMAC), cetyltrimethylammonium bromide (HTMAB) and cetylbenzyldimethylammonium chloride (HBDMAC). The results indicate DSDMAC is less toxic than the other two surfactants and that it biodegrades rapidly at both lower (2.5 mg/L) and higher (10 mg/L) concentrations.

SynopsisMulticomponent gel formulations capable of assimilating, simultaneously, several active ingredients of potential application in the cosmetic field were studied.The possibility of formation of a transparent gel was determined using a method which consisted in the optimization of several lipophilic basic compositions, composed of oil, a mixture of surfactants, a sunscreen agent, several vitamins and antioxidants situated in the base of a regular tetrahedron that symbolized the considered system. To this, a polar phase made of water, a cosolvent and urea in appropriate proportions and situated in the fourth vertex, was progressively added.It may be concluded, that the use of phase diagrams on cosmetic systems, constitutes a useful way to select the components and their mutual ratios, allowing an adaptation to the specific requested conditions of formulation.

Alkyl sulphates of the general formula CH2n + 1-O-SO3Na and alkyl sulphonates of the general formula CnH2n + 1-SO3Na, where n = 8, 10, 12, 14 in each series have been tested for biodegradability with the modified OECD screening test No. 301 E, and for toxicity with Daphnia magna and with Photobacterium phosphoreum (the Microtox(TM) test)). The results show that both alkyl sulphates and alkyl sulphonates are biodegraded with the alkyl sulphates degrading more rapidly under the test conditions. The alkyl sulphates also have higher toxicity to both test species and for both alkyl sulphates and sulphonates the toxicity increases linearly with increasing molecular weight of the surfactant.

The aim of this work has been to undertake a systematic study of wool chemical reactivity against sodium hypochlorite solutions at different pH levels in the absence and presence of surfactant solutions. The degradative effect on wool fibers of the oxidative treatments has been considered in terms of the cysteic acid formed as a consequence of cystine residue rupture. In addition, the adsorption of the surfactant by the fibers during the chlorination treatments has been determined, in an attempt to correlate both parameters (cysteic acid and surfactant adsorption) in order to optimize the process.

SynopsisDiffusion tests of anionic, amphoteric and mixtures of amphoteric/anionic surfactants have been performed using a collagen film.A sensitive potentiometric method has been developed to determine the surfactant diffused avoiding the interferences observed in the usual analytical measurements due to the simultaneous presence of amphoteric/anionic surfactants.From the results obtained it is evident that the surfactant mixtures exhibit a synergistic behaviour as there is a mutual inhibition of the surfactant diffused through the collagen film.Empirical equations have been derived to describe the diffusion process of both the individual surfactants and mixtures of surfactants which allow the diffusion of the individual surfactants and the inhibition of diffusion in mixtures to be quantified.

The physicochemical properties of dispersions made with the cationic resin Hercosett 57 and anionic surfactants have been investigated. The influence of the hydrocarbon chain and the anionic groups of surfactants has been investigated to determine the relationship between the components and their interactions. The application of resin surfactant complexes on untreated wool samples to confer shrink resistance has also been investigated.

Synopsis From a dermatological point of view, it is important to know what is the irritation potential of surfactants on human skin. Recent research trends have been oriented towards the establishment of new 'in vitro' techniques that will avoid animal experimentation. In this paper, some results on the rate of diffusion of different anionic surfactants through both cellulose acetate and collagen membranes are described. A correlation between results of diffusion through the protein membrane and results published on the same surfactants and their irritation potential during 'in vivo' experiments appears possible.

Hercosett resin was applied to untreated wool samples using dispersions made with a cationic Hercosett resin and different optical brightener agents in order to improve both brightness and shrinkproofing properties. The brighteners used in this work were Blankophor BA liq B, Uvitex CF-200, Univtex NFW, and Uvitex WGS. The physi cochemical properties of the dispersion systems were also investigated.

The use of micellar systems as vehicles for applying Hercosett resin and hydrogen peroxide on virgin wool has been investigated. For this purpose phase diagrams of micellar solutions with Hercosett resin and nucleophilic reagent were produced to determine the corresponding areas of monophasic solubility. The shrink resistance conferred to treated wool and the damage produced in the physico-chemical properties of keratin fibers have also been investigated.

Anti‐shrinkage procedures based on the deposition of Hercosett on untreated wool fibres combined with either the use of an amphoteric surfactant or mixed micelles of amphoteric/anionic surfactants are described. Specific molar ratios of the surfactants were found to promote good stability of the bath, giving area felting shrinkage values of the treated fabrics less than 10%.

ABSTRACT Microemulsion regions in systems of commercial nonionic surfactant, water and aliphatic hydrocarbon have been determined. The influence of hydrocarbon chain length, nature of surfactant and temperature in microemulsion formation was studied. Textile deter-gency tests of these microemulsions, in conditions of minimum mechanical energy and at low temperature showed that they are highly efficient to promote soil removal.

A study is reported of the adsorption mechanism of two ionic surfactants (sodium dodecyl sulphate and hexadecyl trimethyl ammonium bromide)on wool in relation to the temperature or time of treatment, either in aqueous or in aqueous-ethanolic media. From the results obtained, the effects of these ionic surfactants on acid and alkaline treatments of wool were evaluated by the alkali-solubility test, determination of the cystine content of the fibres, and analysis of the new amino acids formed during the treatment of wool fibres with methylamine or dimethylamine.