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What Are the Common Ways to Identify Textile Fibers?

fabrics

Samuel RyanSamuel |

With the continuous progress and development of science and technology, textile technology is also constantly updated and iterative, more and more materials can be used in the textile process. Since there are so many textiles on the market, do you know how to identify those textile fibers? Today we will introduce a few simple methods.

cotton

1. Burning method

In our daily life, we most commonly used, but also one of the most simple method is the burning method. Because different textile fibers have different chemical compositions, the characteristics of burning are also different. For example, whether they ignite easily, whether they show thermoplasticity, the smell of burning and the characteristics of the ash after burning. These aspects allow us to distinguish between textile fibers that are protein fibers and those that are cellulose fibers. Here are two simple examples, for example, silk burns with the smell of burning hair, bamboo fiber burns with the smell of burning paper.

2. Microscopic observation method

The morphology of different fibers under the microscope is different, including the cross-section of the fiber as well as the shape of the longitudinal cross-section. However, it should be noted that through the microscope can only identify the textile fibers belong to which fiber class. For example, the longitudinal form of silk under the microscope is smooth, while the cross-section is irregularly triangular; while the longitudinal state of polyester fibers is rod-shaped, and the cross-section of the smooth surface of the round. Of course, the use of the microscope here, the same need to pay attention to the operation of the microscope notes.

microscopy

3.Dissolving method

Compared with other fiber identification methods, the dissolution method can be said to be one of the most effective test method. Its basic principle is to place different fiber materials in different chemical solutions or placed in different temperatures of chemical solutions, according to their reaction with chemical solutions to do a simple identification.

The specific operation method is as follows: place the fiber material to be identified into the test tube, inject the chemical solution, and then gently stir with a glass rod to observe the dissolution of the fiber in the corresponding solution. It should be noted that if the fiber to be identified is very small, the fiber can be placed on a slide, and then drop into the corresponding solution, and finally observed under the microscope. Although the dissolution method is one of the most effective methods for detecting fibers, it is necessary to always observe the characteristics of the dissolution process, such as the temperature and speed of dissolution.

 

4. Melting point method

Different fiber materials, they melt at different temperatures, so according to the melting point to distinguish between the various fibers is also a feasible way. However, the determination of the melting point of fibers also requires the use of a microscope to determine the melting point of the fibers to be tested on a professional microscope with a heated carrier stage and a thermometer. It should be noted that the melting point method is particularly suitable for the identification of synthetic fibers, as their melting point is particularly pronounced compared to other fiber materials.

5. Reagent coloring method

As mentioned earlier, various fiber materials can show different forms under the microscope. With the different structure of the fibers, we can distinguish them by their coloring of iodine or potassium iodide solution. For example, for white fibers, we can distinguish them according to the degree of darkness or lightness of the color after coloring. If they are colored fibers, we need to discolor these fibers before coloring. Here the reagent preparation method is also very simple, only need to add 20 grams of iodine in one hundred milliliters of saturated potassium iodide solution can be prepared.

6. Dyeing method

The main principle of the dyeing method is to use the reaction of different fiber materials to the dyeing material as the basis for classification. Dyeing methods can be simply divided into two types, one is the cold dyeing method and the other is the boiling dyeing method.

For the cold dyeing method, 2.5 grams of direct indigo 2B, 3 grams of acid magenta 6B, and 5 grams each of picric acid and tannic acid are required. Pour the above ingredients into 50 ml of ethanol to dissolve completely and dilute with 500 ml of distilled water. Take out the fiber material to be identified and put it into the solution for dyeing. After the dyeing is completed, wash the fiber with cold water and squeeze out the water for observation.

In the case of the boiling dyeing method, it is necessary to prepare 1 gram each of acid magenta and concentrated saline light yellow, and 0.5 grams each of dispersed blue GF and tryptic bleach T. Unlike the cold dyeing method, after the completion of the dyeing of the fiber is removed, it needs to be placed in boiling water for 3 minutes, and then rinsed 3 times, and finally put into the concentration of 0.1% of the pancreatic plus bleaching T solution for cleaning, squeezing out the water for observation.

7. Infrared absorption spectroscopy

The principle of this method is that the chemical groups of different fibers are different, so in the infrared radiation will show different characteristic absorption bands. The characteristic absorption bands of different fiber materials will appear in different places, take polyester and acrylic as an example, polyester has characteristic absorption bands at 1725 cm, while acrylic will have characteristic absorption bands at 2240 cm. In practice, we need to compare the observed infrared absorption spectra with the known infrared absorption spectra to ultimately determine what the fiber material is.

In fact, the judgment methods of fiber materials are far more than the several listed above, and in the actual identification, it will not adopt only one method to identify the fiber materials, but through the comparison of many aspects to be able to come up with the final result. But the most commonly used is to use the combustion method to identify chemical fibers and natural fibers, as well as the microscope observation method to distinguish between plant fibers and animal fibers.