The conventional identification methods of textile fibers include hand feeling, burning method, microscope observation, chemical dissolution, coloring agent, fluorescent color, melting point method, gravity method, birefringence method, system identification method and so on.
The way of hand feeling is based on the appearance, color, length, thickness, strength, elasticity, touch and impurity of fiber. It relies on human sensory organs to identify fibers. For example, the difference in length of natural fibers, length uniformity, and chemical fiber length are usually more neat; cotton fiber is thin and soft, short length, often with various impurities and defects; hemp feeling is coarse; wool fiber is long, curled, soft and flexible; silk with special luster fiber is thin and soft.
Dry and wet strength difference of viscose fiber of chemical fiber in the wet strength, especially low, can change its strength to distinguish it from other fiber soaked observation, and synthetic fibers due to its appearance. To a certain extent, and the difference between using visual method is difficult to handle, must be identified by other methods. But the nitrogen fiber is elastic fiber. Its biggest feature is high elongation and high elasticity. It can stretch to more than 5 times at room temperature, which can be identified by this characteristic.
Combustion is one of the most common methods to identify fiber. It uses the chemical composition of the fiber, and its combustion characteristics are different to distinguish the kinds of fibers. According to all kinds of fibers near flame, contact flame, different phenomena after leaving the flame, and the odor generated during combustion and the state of residues after combustion, we can distinguish fiber categories.