Masters Theses

Rongguo Zhao

Date of Award

5-1998

Degree Type

Thesis

Degree Name

Master of Science

Major

Textiles, Retail, and Consumer Sciences

Major Professor

Larry C. Wadsworth

Committee Members

Kermit E. Duckett, Gajanan S. Bhat, Dong Zhang, Qin Sun

Abstract

One of the objectives of this project is to improve the dyeability of PET and PP spunbond (SB) nonwoven webs by plasma treatment in order to develop environmentally friendly dyeing process. Because of the nature of chemical inertness and its super molecular structure, PET fibers are almost only colored by disperse dyeing. This technique usually produces more wastewater carrying disperse dyes, carriers and other potentially hazardous chemicals, which must be purified before being discharged into the environment. There is no effective way to color PP fiber by conventional dyes. Surface modification of these hydrophobic fibers has proven very important to reach this goal. Spunbond PET nonwoven webs were treated by (SO2+O2) plasma and (N2+H2+He) plasma. The effects of plasma treatment on the dyeability were studied by colorimetry and DSC analysis. Surface characterizations such as optical microscopy, scanning electron microscopy, and Fourier Transition Infrared spectroscopy (FTIR) were conducted. The research results showed that the dyeability of PET and PP SB webs was significantly improved by plasma treatment. Functional groups were introduced onto the fiber surface and crystallinity was increased with the plasma treatment time. Functional groups played the predominant role in improving dyeability even though the increased crystallinity potentially reduced this improvement. It was concluded that (SO2+O2) plasma and (N2+H2+He) plasma could make the PET and PP SB nonwoven webs easily colored by conventional water-soluble acid dye, which is more environmentally friendly. The (SO2+O2) plasma treated fiber demonstrated a "Skin-Core" type structure. The "Skin" is a polarized layer with many functional groups, which is approximately 1.8 microns in thickness. The "Core" is the inner of fiber without plasma affect. The "Skin" layer is the key in improving the dyeability of hydrophobic fibers. Surface chemical changes after oxygen-containing plasma treatment were detected by the means of FTIR.

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