Dragan Jocic

Shrinkage Properties of Wool Treated with Low Temperature Plasma and Chitosan Biopolymer

Low temperature plasma treatments of wool modify only the cuticle surface of the fibers, improving their surface wettability, dyeability, fiber cohesion, and shrink resistance. The shrink-resist properties obtained with plasma treatment do not impart a machine-washable finish, which is an important end-user demand. However, the shrink resistance of air plasma. treated wool is suitably enhanced by a subsequent biopolymer chitosan application. Using a qualitative colorimetric method, chitosan adsorption is shown to increase after treatment with air plasma. SEM observations yield information about the etching effect and chitosan adsorp tion. Given that both kinds of treatments, air plasma and chitosan, are environmentally acceptable, a new ecological shrink-proofing process is proposed.

Shrinkage Properties of Peroxide-Enzyme-Biopolymer Treated Wool

Incorporating an enzyme in the alkaline peroxide treatment bath enhances wool wet-tability and the effectiveness of subsequently applied chitosan biopolymer. Wool whiteness is also significantly enhanced. Wool knitted fabric thus treated is shrink resistant at the machine-washable level, which is one of the most important end-user demands. The formation of ionic bonds between the new sulphonic groups generated on the wool fiber surface and chitosan contribute to the shrink resistance of H2O2 + enzyme/chitosan treated wool. As a result of excessive increases in enzyme concentration in the peroxide bath, the wool surface cysteic acid content decreases, thus diminishing both the efficiency of post-applied chitosan solution and the shrink resistance.

Influence of a Chlorination Treatment on Wool Dyeing

We examined the exhaustion and penetration of four wool dyes with different struc tures and different dyeing characteristics on untreated and Basolan DC treated wool fibers. The results indicate that chlorination contributes considerably to an increase in the rate of dye exhaustion as well as dye penetration rates. A comparison of these parameters shows that in the case of chlorinated wool, surface adsorption processes precede dye penetration, indicating a change in the surface characteristics of the wool. We measured the extent of wool damage using the alkaline solubility method, and found that chlorinated wool could compensate for differences in dyeing behavior of different wool dyes.

The Influence of Surface Modification on Related Functional Properties of Wool and Hemp

The new concept of the combined treatment consisting of specific fibre surface tailoring and activation prior to biopolymer or enzyme post-application is introduced. Low-temperature plasma treatment is considered as very useful for superficial treatment of wool and hemp. Some interesting combinations of low-temperature plasma and enzymatic treatments are presented in this paper. These treatments result in an increase in wettability, dimensional stability, polymer adhesion and dyeability of both, wool and hemp fabrics.

CONDUCTIVITY MEASUREMENT : A SIMPLE METHOD FOR DETERMINING DYE/SURFACTANT INTERACTION

Surfactants present in the dyebath are responsible for a considerable change in the state of dye in solution, predominately caused by interactions between dye and sur factant. Among several known methods for investigating these interactions, the con ductivity measurement is a simple and accessible method for determining the degree of interaction between direct or acid dye and nonylphenolethoxylates. In order to explain the results conveniently, a fraction named the conductance ratio is defined and used as a measure of the degree of dye /surfactant interaction. The kind of surfactant does indeed exert significant influence on the degree of interaction.