1、 Hand vision method

        It identifies fibers according to their appearance, color, hand feeling, stretching and other characteristics. It can be divided into natural fibers and chemical fibers. For example, natural fiber length uniformity is poor, while chemical fiber length is generally neat. Among natural fibers, cotton fiber is short and fine, often with impurities and defects. Hemp fiber feels rough and hard. Wool fiber is curly and elastic. Silk is long, slender and glossy.

        Among chemical fibers, viscose fibers have great differences in dry and wet strength, and spandex has high elongation. Using these characteristics, they can be distinguished. Other chemical fibers are difficult to distinguish by hand feeling and visual measurement because of their similar appearance characteristics and human behavior.

2、 Combustion experiment method

        Combustion method is a simple method to identify textile fibers. He roughly distinguishes fibers according to their burning characteristics. The method of identification is to take a small bunch of unknown fibers, clamp them with tweezers, slowly approach the flame, observe the burning state when the fibers approach the flame, contact the flame, leave the flame, as well as the smell emitted during combustion and the characteristics of residues after combustion, so as to roughly identify the fibers.

        Acetate fiber: melts and shrinks near fire. It burns immediately in case of fire, and the burning speed is slow. Although acetate fiber is also cellulose fiber, it is semi synthetic fiber after acetate esterification. The ash is black, loose and crisp. Unburned parts become hard lumps.

        Polyester: when burning, it curls, melts and smokes, and the flame is yellow. When burning, it emits fragrant fragrance, and the ashes are black brown glass balls, which can be broken by hand.

        Nylon (nylon): when in fire, it melts and burns slowly. When burning, it is smokeless or slightly white smoke. The flame is very small and blue. It smells of celery when burning. The ash is light brown glass, round and spherical, which is not easy to be broken.

        Nylon: it shrinks quickly when approaching the fire and goes out when leaving the fire. There is a pungent chlorine smell when burning. The ashes are amorphous black hard blocks.

        Vinylon: it shrinks fast when burning, but burns slowly. There are few flames and black smoke. There is aldehyde smell when burning. The ashes are brown amorphous hard blocks that can be crushed.

        Acrylic fiber: it melts while burning in case of fire, and the burning speed is very slow. The flame is white and bright. Sometimes there is a little black smoke and fishy smell. The ash is a small black hard ball, very fragile.

        It is easy to identify fibers by combustion method, but it is difficult to judge blended products. For interwoven fabrics, a yarn is taken from the warp and weft directions (i.e. the straight and horizontal directions) and burned separately

        Combustion method is only applicable to single component fibers, yarns and fabrics, while for mixed component fibers, yarns and fabrics, as well as fibers and textiles after flame retardant or other finishing, it is often difficult to identify with combustion due to changes in combustion characteristics

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