M. R. Juliá

Wool Treatments with Mixtures of Sulphite and Amphiphilic Cationic Protein Hydrolysate

Derivatives of collagen and keratin hydrolysates are frequently used to improve the cuticular surface of human hair, mainly when an oxidative or reductive treatment is involved. In this paper, a similar reductive treatment applied to wool in the presence of an amphiphilic cationic protein hydrolysate leading to a considerable reduction in shrinkage with no significant change in physico-chemical properties, is reported. The influence of the experimental treatment conditions on the effectiveness of the process by evaluation of different parameters such as shrink-resistance, wetting time, cysteine formation, subjective handle assessment, mechanical properties and dyeing behaviour at low temperatures is studied and discussed.

The time dependence of chitosan/nonionic surfactant solution viscosity

The measurement of the viscosity of semiconcentrated chitosan (0.08–0.14%) solutions in the system with octaethyleneglycolmonon-dodecylether (C12E8) was carried out using Cannon-Fenske capillary viscometer. The interaction was—as expected—very weak, vut when the time dependent hydrodynamic behaviour of the system was considered, the interaction has been established at particular surfactant concentrations. The most significant time dependence is shown in a form of sudden viscosity drop in a region close to and above CMC value of the surfactant, which implied existence of the interaction between chitosan and surfactant. At low surfactant concentrations viscosity values vere constant with increasing surfactant concentration, but solution also showed time dependent decrease in the viscosity which has been connected with well known time dependent viscosity of pure chitosan solution.The viscometry enabled monitoring of the extent of chitosan/surfactant association by establishing the viscosity decrease rate constant. The rate constant was derived from the first order constant of the quadratic polynomial curves used for the approximation of experimental values when these are presented in the form of viscosity-time profiles. This method showed the existence of critical surfactant concentration values (C1,C2 andC3). These values are closely connected with the proposed interaction model which is based on the assumption that spherical surfactant micelles are bound by chitosan molecule.

Synthesis and properties of Nα-lauroyl-L-arginine dipeptides from collagen-lauroyl-L-arginine dipeptides from collagen

In order to obtain protein-based amphoteric surfactants with antimicrobial properties, Nα-lauroyl arginine dipeptides have been prepared by condensation between Nα-lauroyl arginine and amino acids which come from a collagen hydrolysate. Some surfactant properties and the minimum inhibitory concentration against Gram positive and Gram negative bacteria have been evaluated. All types of compounds presented a surfactant-like behavior. Furthermore, the compounds described in this paper may be considered as mild preservative or protective substances.

30—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART I: THE INFLUENCE OF THE SURFACTANT CHAIN LENGTH

A kinetic study of the formation of Hercosett–alkylsulphate aggregates is reported. The stability of the turbidity that the aggregates confer to the solution was investigated as a factor of time and the concentrations of each surfactant, i.e., C8−, C10−, C12−, and C14−alkylsulphates.

14—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART III: THE INFLUENCE OF ELECTROLYTES AT VARIOUS pH VALUES ON THE SHRINKAGE OF KNITTED WOOL FABRICS

The interaction between a cationic resin, such as Hercosett, and anionic surfactants is greatly affected by the pH of tbe media as well as by the presence of electrolytes in the treatment bath A study IS presented of how both factors affect tbe shrink-resist properties of the Hercosett-surfactant aggregates on wool fibres for knitted wool fabrics pre-treated with methylamine or hydrogen peroxide.

THE INTERACTION OF IONIC SURFACTANTS-RESINS FOR IMPROVING EXHAUSTION ADHESION AND SPREADING OF PREPOLYMERS ON KERATIN FIBRES

ABSTRACT A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C8-C14) in preventing the shrinkage of wool samples pretreated with hydrogen peroxide is reported and a kinetic study of the formation of these aggregates as well as a mechanism by which they exhaust on wool fibres are suggested.

31—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART II: THE INFLUENCE OF VARIOUS ALKYLSULPHATES ON THE SHRINKAGE OF KNITTED WOOL FABRICS

A study of the effect of the aggregates formed between Hercosett and alkylsulphates (C8–C14) in preventing the shrinkage of wool samples pre-treated with methylamine and hydrogen peroxide is reported. The amount of surfactant adsorbed on each pre-treated wool sample was estimated, and a mechanism by which the aggregate exhausts on the fibre is suggested.