Fluorescence refers to a cold luminescence phenomenon of photoluminescence. When a substance at room temperature is irradiated by incident light of a certain wavelength (usually ultraviolet or X-ray), it absorbs light energy and enters an excited state, and immediately de-excites and emits outgoing light with a wavelength longer than that of the incident light (usually the wavelength is Visible light band); and once the incident light is stopped, the luminescence phenomenon disappears immediately. Outgoing light with this property is called fluorescence. In daily life, people usually refer to all kinds of weak light as fluorescence in a broad sense, without carefully investigating and distinguishing their light-emitting principles. Fluorescence has a wide range of applications in the fields of biochemistry and medicine. People can stick fluorescent chemical groups to biological macromolecules through chemical reactions, and then sensitively detect these biological macromolecules by observing the fluorescence emitted by the tracer groups.
Let's see how to distinguish non-woven fabrics by fluorescence method:
Fluorescence method:
The non-woven fibers are irradiated by ultraviolet fluorescent lamps, and the non-woven fibers are identified according to the different properties of the non-woven fibers and the different fluorescent colors of the non-woven fibers. The fluorescent color of various non-woven fibers specifically shows:
(1) Cotton and wool fibers: light yellow;
(2) Mercerized cotton fiber: light red;
(3) Jute (raw) fiber: purple-brown;
(4) jute, silk, nylon fiber: light blue;
(5) Viscose fiber: white and purple shade;
(6) Bright viscose fiber: light yellow and purple shade;
(7) Polyester fiber: white light and blue sky light are very bright;
(8) Vinyl fiber: light yellow and purple shade.