Optical Characterization of Some Modern “Eco‐Friendly” Fibers*

Abstract

Fibers that are termed "eco-friendly" or "biodegradable" by manufacturers are increasingly being used in textile products such as apparel and carpeting to appeal to the ever more environmentally aware public. As such, these modern fibers are expected to begin showing up more often in forensic casework, and it is important that the forensic examiner recognize them. This study employed polarized light microscopy (PLM) and Fourier transform infrared (FTIR) microspectroscopy to characterize selected fibers of azlon, polylactic acid (PLA), cellulose composites of alginate or chitin, and bamboo (viscose rayon). Fiber cross-sections, refractive indices, melting points, solubilities, and FTIR measurements were conducted. Results indicate that the azlons and PLA fibers are easily distinguishable from other textile fibers by their optical and chemical properties. The cellulose composites show only small differences in comparison with other cellulose-based fibers, while bamboo viscose rayon is indistinguishable from normal viscose rayon.

The Effects of Environmental Exposure on the Optical, Physical, and Chemical Properties of Manufactured Fibers of Natural Origin

“…0.03. These values are consistent with the modern generation of azlons compared to the azlons produced prior to the 1950s, which had much lower birefringence values of 0–0.006 . The modern fibers tested exhibited parallel extinction with some partial (undulose) extinction, and a positive sign of elongation.…”

“…Currently, new production methods, including incorporating polyvinyl alcohol into the spinning solution , have resulted in modern azlons. These azlons have different optical properties than their predecessors . Textiles may be 100% azlon or blended with cotton, silk, nylon, or wool.…”

“…PLA is currently being mass‐produced by companies in the United States. (Natureworks ® , LLC, Minnetonka, MN) , Japan (Kanebo ® , Tokyo) , and China . PLA textile products include apparel, upholstery, and carpet fibers.…”

Facile Preparation of Soy Protein/Poly(vinyl alcohol) Blend Fibers with High Mechanical Performance by Wet-Spinning

“…13 The absorption bands at 1636−1680, 1533−1559, and 1241−1472 cm −1 were ascribed to the amide I, amide II, and N−H bending (amide III) vibrations in peptide bonds forming the primary backbone of soy proteins. 13,14 This result indicated that the SP and PVA in the polar solvent (formic acid) had a good compatibility for homogeneous blending.…”

Soybean Protein Fibres (SPF)

“…The morphological structure of SPF consists of less oriented sheath and well oriented microfibrilar core. The fibres have about 10% of hydrophilic groups in amorphous regions (Mathur & Hira, 2004 (Brinsko, K. M., 2010).…”