Effects of Hydrogen Peroxide on Common Aviation Textiles
Modern transportation systems are subject to unintentional contamination from infected passengers, as well as deliberate contamination from criminals and political adversaries. Hydrogen peroxide has been used for years as a disinfectant in the medical community and is under consideration in the dilute vapor form as a decontaminant/disinfectant/sterilant for transportation vehicles like aircraft, buses, subway trains, ambulances, etc. Although the biological efficacy of STERIS Corporation’s Vaporized Hydrogen Peroxide (VHP® a registered trademark of the STERIS Corporation, Mentor, OH) technology has been demonstrated elsewhere, the compatibility of the process with typical aircraft materials has not been rigorously established. The present report documents a materials compatibility evaluation involving the effects of hydrogen peroxide exposure on the mechanical properties and flammability of the following commercial-grade textile materials: wool, nylon, polyester, Nomex®, and leather.
Effect of Urea on Bleaching of Wool with Hydrogen Peroxide Under Alkaline and Acidic Conditions
The effect of urea on the alkaline and acidic hydrogen peroxide bleaching of wool has been investigated. There was an improvement in the whiteness of the wool or, alternatively, a considerable reduction in the bleaching time using a concentration of 100-200 g/l urea in the bleaching bath. No significant differences were observed at lower concentration of urea (less than 100 g/l) in the bleach bath. Alkali solubility of wool flannel increases with urea concentration during bleaching and often remains within tolerable limits.
On a correlation between the surface chemistry and the felting behavior of wool
The felting behavior of wool fibers is found to be correlated with their flocculation properties. The interaction between the fibers is suggested as the common factor responsible for this correlation. It is observed that in a felting medium there is attraction between natural wool fibers. Such attraction is observed to be greatly diminished, or absent, after the wool has been shrinkproffed by any one of several chemical modification treatments. Hydrophobic attraction and electrostatic repulsion are proposed as significant components of the interaction between fibers in aqueous media. These components are linked to the surface chemistry of natural and chemically modified wool. It is proposed that the hydrophobic nature of the fiber surface promotes the felting shrinkage of natural wool fabrics, that shrink-resist chemical treatments of wool top make the fiber surface more hydrophilic and may increase the electrostatic repulsion between fibers, and that the influence of surfactants on felting depends on the adsorption energy of the surfactant at the fiber surface. These ideas are presented as a guide for the development of further shrink-resist chemical modifications of wool.