Shouhua Niu

Surface Characteristics of Wool and Poly ( ethylene Terephthalate) Fabrics and Film Treated with Low-Temperature Plasma Under Atmospheric Pressure

Wool and poly ( ethylene terephthalate) fabrics and film were treated with low-tem perature plasmas of helium/argon or acetone/argon under atmospheric pressure for 10 to 180 seconds. Although argon itself cannot independently generate a plasma under atmospheric pressure by applying high frequency voltage, it is easily generated by adding a small quantity of helium or acetone to argon gas. Wettability of the fabrics and surface tension of the film increased considerably with the treatment within 30 seconds. ESCA analysis was used to elucidate the surface chemical composition of fibers treated with atmospheric low-temperature plasma. Relative O1 s intensity in creased considerably and oxygen was incorporated in the form of —CO— and —COO— on the fiber surface. From these results, it appears that low-temperature plasma by atmospheric pressure discharge is effective for modifying the polymer surface, as it acts in the same fashion as low-temperature plasma by glow discharge.

Dyeing Properties of Wool Treated with Low-Temperature Plasma Under Atmospheric Pressure

Merino wool top was treated with low-temperature plasmas of helium/ argon and acetone/argon under atmospheric pressure for 30 seconds and then dyed with two leveling-type acid dyes, CI acid orange 7 and CI acid red 18, and two milling-type acid dyes, CI acid blue 113 and CI acid blue 83. Dyeing rate and saturation dye exhaustion increased with the atmospheric low-temperature plasma treatments as with the dyeing of wools pretreated with low-temperature plasma by glow discharge of O2 and CF4. In particular, helium/ argon plasma was much more effective than acetone / argon plasma at improving dyeing properties, except for CI acid blue 113.

Effect of Crosslinking Agents on Water Repellency of Cotton Fabrics Treated with Fluorocarbon Resin

Cotton fabrics and cellulose films treated with fluorocarbon resin (Asahi Guard AG-480 ) with and without crosslinking agents (isocyanate blocked copolymer and aziridine) were washed and subsequently heat treated. Water repellency of the fabrics decreased with washing and recovered with heat treatment. The decreased water re pellency with washing was controlled by using the resin with a crosslinking agent. To investigate surface tension and surface chemical composition of the fabrics after washing and subsequent heat treatment, the contact angle to water and critical surface tension of the films were measured along with an ESCA analysis of the fabrics. Adding cross linking agents to the fluorocarbon resin treatment controlled the decrease in F1s intensity and the increase in O1s intensity with subsequent washing.

Effect of Heat-Setting Temperature on Alkali Hydrolysis of Poly ( ethylene Terephthalate) Fibers

Poly(ethylene terephthalate) (PET) fiber was heat set at 100 to 220°C and then hydrolyzed with 10% aqueous sodium hydroxide solution at 90°C for 60 and 120 minutes. Weight loss from the alkali hydrolysis initially decreased with increased heat- setting temperature up to 140°C and then increased at temperatures above 140°C. This phenomenon is similar to those with hydrazine treatment and with disperse dyeing of heat-set PET fibers and can be attributed to changes in the fine structure, especially in the amorphous regions of the fiber, caused by heat-setting treatment at different temperatures. Crystallinity and disperse dye uptake for the hydrolyzed PET fiber increased with hydrolysis, indicating differences in the fine structure from the outer to the inner regions of the fiber.

EFFECT OF HEAT-SETTING TEMPERATURE ON THE HYDRAZINE TREATMENT OF POLY (ETHYLENE TEREPHTHALATE) PARTIALLY ORIENTED YARN

Poly (ethylene terephthalate) partially oriented yarn (PET POY) was heat set at 100 to 220°c in a fixed state and then treated with hydrazine. Although crystallinity of the heat-set PET POY increased with increased heat-setting temperature, weight loss from the hydrazine treatment initially decreased at a temperature up to 120°c and subsequently increased above 120°c. The hydrazinolyzed POY fiber is dyeable with acid dyes because of the hydrazide groups incorporated by hydrazinolysis. Nitrogen content and dye exhaustion with CI acid orange 7 showed trends similar to the weight loss of the hydrazinolyzed POY fibers. On the other hand, the dyeability of the hydrazinolyzed POY fibers with CI disperse violet 1 was lower than that of the untreated fibers. Many cracks appeared on the surface of the hydrazinolyzed fibers, and they were smallest on the fibers that were heat set at 120°c.