Take out several warp and weft yarns of two unknown webbings and burn them with a lighter. Observe some physical phenomena during the burning process to determine the raw materials of the warp and weft yarns. During the burning process, observe the flame, melting condition, odor emitted, and the condition of the ash after burning.
Nylon webbing: Melts and shrinks when close to the flame Melts and burns, drips and bubbles Does not continue to burn directly Smells like celery Hard, round, light, brown to gray, beaded
Polyester webbing: Melts and shrinks when close to the flame Melts and burns, drips and bubbles Can continue to burn, a few have smoke Very weak sweetness Hard round, black or light brown
Cotton fiber and hemp fiber
Both cotton fiber and hemp fiber burn as soon as they are close to the flame, burn quickly, and the flame is yellow with blue smoke. The difference between the two in the odor emitted by burning and the ash after burning is that cotton burns and emits the smell of paper, while hemp burns and emits the smell of plant ash; after burning, cotton has very little powder ash, which is black or gray, while hemp produces a small amount of grayish white powder ash.
Nylon and Polyester
Nylon (nylon) is the scientific name of polyamide fiber. It shrinks and melts into a white gel when it is close to the flame. It melts, drips and bubbles in the flame. There is no flame when it burns. It is difficult to continue burning without the flame. It emits a celery smell. After cooling, the light brown molten material is not easy to grind.
Polyester is the scientific name of polyester fiber. It is easy to ignite. It shrinks when it is close to the flame. It emits black smoke while melting. It has a yellow flame and emits an aromatic smell. The ashes after burning are dark brown lumps and can be crushed with fingers.
Acrylic and Polypropylene (PP)
Acrylic is the scientific name of polyacrylonitrile fiber. It softens and shrinks when it is close to the flame. It emits black smoke after ignition. The flame is white. It burns quickly after leaving the flame and emits the acrid smell of burnt meat. The ashes after burning are irregular black lumps and are easy to break with hands.
The scientific name of polypropylene is polypropylene fiber. It melts and shrinks when it is close to the flame. It is flammable. It burns slowly and emits black smoke when it is away from the flame. The upper end of the flame is yellow, the lower end is blue, and it emits a petroleum smell. The ashes after burning are hard, round, light yellow-brown particles, which are easy to break by hand.
Vinylon and chlorofiber
The scientific name of chlorofiber is polyvinyl alcohol formal fiber. It is not easy to ignite. It melts and shrinks when it is close to the flame. There is a little flame at the top when it burns. When the fibers are melted into a gelatinous state, the flame becomes larger, there is thick black smoke, and it emits a bitter and fragrant smell. After burning, small black beads are left, which can be crushed with fingers.
Chlorofiber is the scientific name of polyvinyl chloride fiber. It is difficult to burn and will go out when it is away from the flame. The flame is yellow, and the lower end is green and white smoke. It emits a pungent, spicy and sour smell. After burning, the ashes are black-brown irregular hard lumps, which are not easy to break with fingers.
Spandex and fluorofiber
The scientific name of spandex is polyurethane fiber. It melts and burns when it is close to the fire. The flame is blue when it burns. It continues to melt and burn away from the fire, emitting a special irritating odor. After burning, the ashes are soft and fluffy black ash. Fluorocarbon is scientifically known as polytetrafluoroethylene fiber, and ISO organization calls it fluorite fiber. It only melts near flames, is difficult to ignite, does not burn, and has a blue-green carbonization at the edge of the flame. It melts and decomposes, and the gas is toxic. The melt is hard round black beads. Fluorocarbon fiber is often used in the textile industry to make high-performance sewing threads.
