Semester

Summer

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Forensic and Investigative Science

Committtee Chair

Patrick Buzzini

Committee Co-Chair

Suzanne Bell

Committee Member

Jacqueline Speir

Abstract

The goal of this study was to determine what characteristics of synthetic wigs are polymorphs; and to report the most discriminating analytical methods for microscopical and chemical examinations of wig fibers for the detection of the most variable features. Synthetic wig fibers are manufactured to take on the appearance of natural hair for either cosmetic or costume use. Subsequently, the characteristics of wig fibers, especially as a collective group within a single wig, can vary greatly from those synthetic fibers collected from garments and household items. A number of samples were collected from 50 brown, blonde and black wigs made of modacrylic, polyvinyl chloride, polypropylene, and nylon fibers. These samples were first studied with light microscopy using both bright field illumination and double polarization. The physical and optical properties of the fibers were documented including: color, longitudinal appearance, the density of the delustrant particles, the force of birefringence, and the sign of elongation. Feature vectors based upon cross-sectional shape and color were compared using cosine similarity measurements to show the high discrimination potential of these two characteristics. Fourier Transform infrared spectroscopy (FTIR) confirmed modacrylic to be the most popular fiber type. Further discrimination of modacrylic fibers based upon the presence of additives and solvent residue was achieved using principal component analysis (PCA) coupled with hierarchical clustering analysis (HCA). Thin-layer chromatography (TLC) indicated there is a wider range of complex dyes that are applied than previously expected.

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