Fibers Identification

The identification of textile fibers is a task frequently performed in a textile laboratory. The need to identify fibers arises in fibers research as well as during fabric production and processing. The identification of an unknown fiber in a yam 

Purpose To make some observations about the reaction of various fibers to an open flame. 

Procedure Obtain 1-2 cm lengths or tufts of the various fibers or yams to be tested from the samples provided. Perform the following tasks and carefully record the information in Worksheet 1 provided below. Worksheets may be adjusted as necessary to suit the purpose of the reader. 

Hold the individual fiber samples to be tested in tweezers or tongs and bring the fibers slowly to the side of a Bunsen burner flame. Make observations. What is the initial reaction Does the fiber shrink Melt Anything else  

Place the fiber in the flame and slowly withdraw it. Does the fiber bum  

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Polyester composition can be determined by hydrolytic depolymerization followed by gas chromatography (28) to analyze for monomers, comonomers, oligomers, and other components including side-reaction products (ie, DEG, vinyl groups, aldehydes), plasticizers, and finishes. Mass spectroscopy and infrared spectroscopy can provide valuable composition information, including end group analysis (47,101,102). X-ray fluorescence is commonly used to determine metals content of polymers, from sources including catalysts, delusterants, or tracer materials added for fiber identification purposes (28,102,103). 

Plant-fiber identification is described in TAPPI T8 and TIO. In order to identify synthetic fibers, it usually is necessary to conduct solubihty and physical properties tests in addition to light microscopy observations. Systematic sampling is required to obtain quantitative information on sample composition. Because different types of pulps contain varying numbers of fibers per unit weight, it is necessary to multiply the total number of each kind of fiber by a relative weight factor, thereby the weight percentage that each fiber type contributes to the sample can be deterrnined. 

Optical properties of fibers are measured by light microscopy methods. ASTM D276 describes the procedure for fiber identification using refractive indexes and birefringence. Other methods for determining fiber optical properties have been discussed (3,38—44). However, different methods of determining optical properties may give different results (42). 

Asbestos fiber identification can also be achieved through transmission or scanning electron microscopy (tern, sem) techniques which are especially usefiil with very short fibers, or with extremely small samples (see Microscopy). With appropriate peripheral instmmentation, these techniques can yield the elemental composition of the fibers using energy dispersive x-ray fluorescence, or the crystal stmcture from electron diffraction, selected area electron diffraction (saed). 

This Chapter provides information on available certified reference and quahty control materials relevant for use in the measurement of airborne contaminants in occupational hygiene. The majority of measurements made in this area worldwide are solvents, dust (total, respirable), elements, oil mist, quartz, fiber identification (asbestos, man-made fibers), mists and gases. 

Merrit, J. (1994), Fiber identification, Textile Consero. Newsl. 27, 9-12. 

Hall, D. M. Practical Fiber Identification Auburn University Auburn, Alabama, 1982. 

Table I. Fiber Identification and Elemental Analyses of Tunacunnhee Fabric Pseudomorphs...

Graff, J. H. A Color Atlas for Fiber Identification The Institute of Paper Chemistry Appleton, Wisconsin, 1940. 

Worksheet 2 Fiber identification by solubility synthetic fibers... 

Details of single fiber analysis have been given by Bresee. Therefore, in this chapter, only highlights of some of the important methods for fiber identification have been considered. 

There is no set procedure for fiber identification. The following is a suggested approach. 

The main practical use of fiber density is in fiber identification. 

Three methods are common, viz, the liquid displacement method, the sink-float method and the density gradient column method. Each of these is a common, standard technique and is fully described in ISO 10119, 1992 (for the determination of the density of carbon fiber), and also in ASTM D 276-87 (reapproved in 1993), which in fact also refers to ASTM D 1505, ASTM D 792, and AATCC, Method 20 (1990) (Fiber identification), each of which deals with the above techniques. ISO 10119 is a very good and concise description of the techniques. However the measurement liquids specified in ISO 10119 of ethanol, methanol, acetone, tricloroethane, and carbon tetrachloride, although suitable for carbon fibers, are not at all suitable for the general range of textile polymers, with the exception perhaps of ethanol and methanol. ASTM D 276 87 recommends the use of / -Heptane for universal application, except, of course for the olefins, such as polyethylene. A range of typical fiber densities is given in Table 4. 

Fibers represent a special case, as such optical properties as refractive index and birefringence are important not so much for their influence on the appearance or performance of the product but as an aid to fiber identification. Fiber optical properties are considered in Chapter 19. Although similar identification techniques are applicable to transparent plastics in general, such tests are not widely used outside the forensic. science... 

Bhatia and Gupta [23] give the reaction to coloring agents for four different fibers, which can be useful in fiber identification. These are listed below ... 

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