Semester

Summer

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Suzanne Bell.

Abstract

Fibers are commonly encountered trace evidence materials that are observed and analyzed in forensic science. The analysis of fibers currently relies upon chromatography, microscopy, spectroscopy, and mass spectrometry (1, 2). While most features of fibers are easily established, the determination and comparison of one important attribute, color, is complex(3, 4). Factors such as environmental conditions may play an important role when identifying, analyzing and comparing color between questions and known fiber samples.;While color can be evaluated subjectively, it can also be characterized instrumentally. This property may observe subtle or significant differences when fibers have been exposed to aging and laundering. These changes cannot be adequately characterized without instrumental analysis. To standardize and quantify these changes, the Commission Internationale de l'Eclairage (CIE) color characterization system was used in this project.;For the comparison of color, microscopical examination remains the key tool (5). The Microspectrophotometry (MSP) instrumentation has become a standard analytical method used for measuring color in trace evidence. It is the preferred and accepted method because it is non-destructive. In this study, ultraviolet-visible Microspectrophotometry (UV-Vis MSP or MSP) in transmittance measurement was used to analyze the kinetics of color on aged and laundered textile fibers. In transmittance microscopy, the transmittance curve of a colored sample is an objective description of its physical characteristics, free from the subjective influence that occurs with the human eye when it perceives color (6). Therefore, the purpose of this research is to objectively measure color change on aged and laundered textile fibers using colorimetry, and statistically evaluating the data obtained to determine how aging and laundering alter the colorimetric data.;Color changes were observed on fibers subjected to the process of aging and washing. Both treatments affected the degradation of color microscopically in fibers. The artificial aging of fibers was seen to affect the saturation of color more than the gloss of the color. The process treatment of washing and aging was seen to affect the gloss of fiber more than the saturation of color within the fiber. Using colorimetry, statistical methods were able to determined where the changes took place and by how much. Unfortunately, CIELab values were unequally affected between colors such that an overall pattern of degradation could not be calculated.

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