Abstract：
Solution dyed fibers are synthetic fibers colored through the addition of insoluble pigmentation to the polymer prior to extrusion. This is in contrast to most textile fibers, which are traditionally colored via immersion in liquid dyebaths following extrusion. Solution dyed fibers are increasing in market share in numerous applications (e.g., apparel, carpet, upholstery), and thus, the microscopic characteristics and variety of pigments used to color them represent unexploited properties in forensic fiber comparisons. This paper presents the development of a microscopical process to first recognize a fiber as solution dyed and subsequently characterize the color and optical properties of each type of pigment found in a given fiber. To this end, a set of 76 fibers, representing polypropylene, nylon, polyester, and rayon, spanning all nominal colors and several consumer applications were analyzed longitudinally and in cross section using a combination of polarized light, fluorescence, and oil immersion microscopy. A given fiber contained between one and six different pigments, and a total of 260 pigments (not all unique) were recognized within this set of fibers. Pigment morphologies were categorized as angular, elongated, rounded, finely divided, or streaky, and about 40% of the pigments fluoresced. Ultimately, this body of data is intended to provide trace evidence examiners with a specific approach to recognize and begin to exploit pigmented fibers encountered in casework.
摘要：
溶液染色纤维是通过在挤出之前向聚合物中添加不溶性色素而着色的合成纤维。这与大多数纺织纤维相反，传统上是通过挤压后浸入液体染浴中着色的。溶液染色纤维在许多应用中的市场份额正在增加(例如，服装,地毯,室内装潢)，因此，在法医纤维比较中，用于着色的颜料的微观特征和种类代表了未利用的特性。本文介绍了一种显微工艺的开发，该工艺首先将纤维识别为溶液染色，然后表征给定纤维中每种颜料的颜色和光学特性。为此,一组76根纤维，代表聚丙烯，尼龙,聚酯,还有人造丝,跨越所有的标称颜色和几个消费应用进行了纵向和横截面分析，使用偏振光的组合，荧光，和油浸显微镜。给定的纤维含有一到六种不同的颜料，并且在这组纤维中识别出总共260种颜料(并非全部是独特的)。颜料形态被分类为角形，细长的，圆形,细碎的,或者条纹，约40%的颜料发出荧光。最终,这些数据旨在为痕迹证据审查员提供一种特定的方法，以识别并开始利用案例工作中遇到的色素纤维。
