Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Engineering Science (Interdepartmental Program)

First Advisor

John R. Collier


Rayon/nylon sheath/core composite fibers with enhanced adhesion were produced using a wire coating type process. One objective of this research was to determine an effective coupling agent and the most appropriate application conditions for maximum interfacial adhesion in the rayon/nylon bicomponent fibers. The second objective was to characterize the interfacial adhesion between the core fiber and the rayon skin. It was found that fumaric acid (FA) was an effective adhesion promotor for rayon/nylon composite fibers since it has difunctionality and steric hinderance necessary to form covalent bonds to both layers. After removal of the spin finish by water washing the nylon core fibers were pretreated with fumaric acid (FA) as an adhesion promoter and then were coated with viscose rayon. The results indicated that the interfacial adhesion in the rayon/nylon composite fibers was significantly improved under the application conditions of 1.0% with 36 second pretreatment time, 1.5% with 18 second pretreatment, and 2% with 9 second pretreatment time. After curing, the FA formed amide bonds to the nylon and ester bonds to the rayon. A fiber pull adhesion test method was developed to test the interfacial adhesion. This method effectively determined the adhesion between the core and the skin. Coating weight loss and interfacial shear stress were determined from the fiber pull adhesion test. A scanning electron microscope (SEM) was used to observe the cross sectional and longitudinal surfaces of these composite fibers before and after the adhesion test to confirm the fiber pull adhesion test results. The fiber linear density and moisture regain were determined. Bending properties of the fabrics made from coated and uncoated fibers were also determined and compared to similar properties of the fibers.