The Chemistry of Forensic Fiber Analysis
Yesterday evening (07 December 2022), Microtrace Research Microscopist Kelly Brinsko Beckert, MS delivered the featured presentation to the Joliet Section Meeting of the American Chemical Society. Her talk, entitled “The Chemistry of Forensic Fiber Analysis,” follows the “Chemistry of Fabrics” theme that the ACS has established for the upcoming National Chemistry Week (16-22 October 2022). Ms. Beckert’s paper explored the various laboratory analyses that may be performed during a forensic examination of a fiber, and how a fiber’s chemistry can impact everything from its cross section to its color and end-use.
Textile fibers include numerous types of fibers, from the natural fibers such as cotton, linen, and silk, to man-made fibers like rayon, polyester, and nylon. The physical, optical, and chemical properties of these fibers can be very different from each other, but one common feature they share is that they are comprised of long chains of molecules that form the basic structure of the fiber. The molecular chemistry of a fiber has a significant effect on its numerous attributes, from the formation of the fiber itself, and the subsequent manufacture into yarns and textiles, to the gross appearance and handle of the woven fabric. It is the chemistries of the polymers, colorants, and finishes that are responsible for these differences, many of which may be tested and exploited during a forensic fiber analysis. Fibers can be classified based on their morphology, optical properties, and molecular chemistry using a combination of microscopy, microchemistry, and infrared microspectroscopy. This talk will explore the various laboratory analyses that may be performed during a forensic examination of a fiber, and how a fiber’s chemistry can impact everything from its cross section to its color and end-use.