How to identify carbon fiber, glass fiber, polyester cotton, aramid fiber, Serofel fiber 5

The difference between glass fiber and carbon fiber!

Fiberglass compared to carbon fiber.

Low modulus, high elongation at break, inexpensive.

However, the self-weight, the workability is not good, and there may be an alkaline reaction with the concrete, purely from a technical point of view.

Fiberglass reinforced concrete columns work better.

Carbon fiber is better for bending reinforcement.

Polyester-cotton, aramid fibers.

Lean on the burn, observe the flames. The flame of the cotton is soft, and finally it burns to ashes, and the polyester will jump and emit black smoke, and burn into hard lumps. Polyester cotton is a combination of the two, and you can generally see the flame jumping, most of the cases are still soft, much like cotton, but in the end it produces a hard block, which is smaller than that of polyester.

Carbon fiber is black and conductive, you can test it with a resistance meter, and the high-temperature resistant lighter does not react at all, and the others are not resistant to high temperatures, and they are deformed as soon as they are burned with a lighter

Content from user: nalip

Experimental part. Textile fiber identification.

First, the purpose and requirements of the experiment, through the experiment, learn several common methods to identify textile fibers, and according to the appearance and internal properties of fibers, identify several common textile fibers. 2. Experimental methods and principles.

1. Hand feel visual method.

The psychological reaction to the feeling of touching the fabric with your hands, due to the different varieties of fabrics, the quality is also different, and the feel effect of the fabric is also quite different. For example, the hand touches the silk textile and feels cold; Pure wool fabric has a warm feeling.

In addition, people can also use the action of force, stretching and scratching with their hands, and then through the observation of their eyes and the feeling of their hands, they can judge the elasticity, strength, wrinkle resistance and fiber type of fabric.

2. Combustion method.

It is to distinguish the types of fibers by using the different chemical composition of fibers and their different combustion properties. Fiber categories are identified according to the state of the fibers when they are close to the flame, when they are in contact with the flame and when they leave the flame, as well as the odor produced during combustion and the characteristics of the residue after combustion.

3. Microscopic observation method.

Microscopy is used to observe the morphological characteristics of fibers to identify various fibers. For example: the natural twisting of cotton fibers, the scales of wool, the horizontal and vertical lines of hemp fibers.

3. Experimental instruments and materials.

Cotton, wool, polyester, viscose, hemp.

Alcohol lamp, tweezers, biological microscope, glass slide, coverslip.

Fourth, the experimental process.

1.Hand feel visual method.

1) Lack of amount of fiber.

2) ** Fiber color gloss.

3) Touch the textile fiber with your hands to feel whether the body and bones of the object are crisp and loose, the surface is smooth and rough, the thin and thick of the object, and the cold and warm of the fabric.

a.First, natural fibers and chemical fibers are identified by combustion.

b.In the case of natural fibers, various types of plant fibers and animal fibers are identified by microscopic observation. If it is a chemical fiber, it is distinguished one by one by combining the differences in the melting point, specific gravity, refractive index, and solubility properties of the fiber.

c.When identifying mixed fibers and blended yarns, it is generally possible to confirm the presence of several fibers with microscopic observation, and then identify them one by one with appropriate methods.

d.For dyed or finished fibers, dyeing stripping or other appropriate pretreatment is generally required to ensure reliable identification results.

Microscope Identification Method: Portable Microscope Recommended.

Compared with the traditional identification tool desktop microscope, the identification of textile fibers can only be limited to the experiment, and can not be universally applied to the factory workshop, or farm, at the transaction and delivery site, while the detection and identification of textile fibers is generally carried out in factories or farms for on-site identification.

The value of in-situ microscopy for textile identification:

1.data sharing; Anyty portable microscope generally integrates the function of digital imaging, and the data observed by the microscope can be presented to all the people present at the same time, which is convenient for discussion and communication.

2.Portability and simple operation; The Anyty portable microscope is highly portable, easy to carry, and simple to operate, which can break through the limitations of time and space, and can be observed in real time in any occasion, which is different from the immobility of traditional microscopes.

3.Inheritance, because the Anyty portable microscope has the function of taking pictures and videos, the images detected anywhere at any time can be stored and backed up, and each of the best identification results can become an accumulation of experience and provide reference materials for the next appraiser! Combustion properties of common fibers:

Fiber near flame phenomenon in the flame after leaving the flame odor ash.

Cotton, near the flame, instant combustion, continuous combustion, afterglow, burning paper smell, very little ash, fine and soft, gray and black flocculent.

Hair: Melt away from the flame, melt and burn, refractory to burn, self-extinguishing, singe-hair, ash, crunchy, black, flocculent, fragile.

Silk melts away from the flame, silk sound, difficult to continue combustion, self-extinguishing, singeing smell, brittle, fluffy, black particles.

Nylon softens and shrinks, blue flame, difficult to continue to burn and self-extinguish, amino odor, light brown transparent bead-like, not fragile.

Polyester, near flame melting, dripping, blistering, continued burning, weak fragrance, hard round, black, light brown, not fragile.

Acrylic Melting near flame burning Melting and ignition Rapid ignition splash Pungent Fragile irregular black-brown lumpy or globular Brittle.

1. Combustion method: natural fiber burning goods have the smell of burning paper, and chemical fiber burning smells not very good.

2. Microscopic identification: natural fibers such as cotton fibers, wool scales, hemp fibers horizontal and vertical lines, silk triangular sections, chemical fiber no.

3. Drug coloring method: the physical and chemical properties of different fibers are different, usually iodine-potassium iodide is added to determine the variety of fiber.

Cellulose fiber refers to all fibers obtained from cellulose polymers, which can be divided into natural cellulose fibers, natural regenerated cellulose fibers and regenerated cellulose modified fibers. Natural cellulose fibers mainly include cotton, ramie, flax and other fibers. Regenerated cellulose fibers are mainly viscose, acetate and bamboo fibers.

Cellulose fiber has a series of characteristics that cannot be fully possessed by a series of synthetic fibers, such as good contact, wearing comfort, physiological safety, hygroscopicity and easy finishing, as well as the easy biodegradability of its products, so nonwovens with cellulose fiber as raw materials have unique uses in medical, nursing, hygiene products, cosmetics and other industrial fields. In developed countries in Europe, the United States and Japan, cellulose fiber has been widely used as an important nonwovens raw material. Biodegradable cellulose fibers include cotton fibers, viscose fibers, cellulose acetate fibers and lyocell fibers.

100 inspectionsFiber composition identification method:

Hand visual inspection method: This method is suitable for textile raw materials in the state of loose fibers.

1) Cotton fibers are shorter and thinner than ramie fibers and other hemp fibers, and are often accompanied by various impurities and defects.

2) Hemp fiber feels coarse and hard.

3) Wool fibers are crimped and elastic.

4) Silk is a filament, long and slender, with a special luster.

5) Among chemical fibers, only viscose fibers have a large difference in strength between dry and wet states.

6) Spandex yarn has a very large elasticity, and it can stretch up to more than five times its length at room temperature.

2.Microscopic observation method: It is to identify fibers according to the longitudinal and cross-sectional morphological characteristics of fibers.

1) Cotton fiber: cross-sectional shape: waist round, with a middle waist; Longitudinal morphology: flat bands with natural twists.

2) Hemp (ramie, flax, jute) fibers: cross-sectional morphology: waist round or polygonal, with a middle cavity; Longitudinal shape: with horizontal joints, vertical lines.

3) Wool fibers: cross-sectional morphology: round or nearly round, some with pith; Longitudinal morphology: scales on the surface.

4) Rabbit hair fiber: cross-sectional morphology: dumbbell type, with hair pith; Longitudinal morphology: scales on the surface.

5) Mulberry silk fiber: cross-sectional shape: irregular triangle; Longitudinal morphology: smooth and straight, longitudinally striped.

6) Ordinary viscose: cross-sectional shape: zigzag, leather core structure; Longitudinal morphology: longitudinally grooved.

7) Rich and strong fibers: cross-sectional morphology: less toothed, or round, oval; Longitudinal morphology: The surface is smooth.

8) Acetate: cross-sectional morphology: trefoil or irregular zigzag; Longitudinal morphology: There are longitudinal stripes on the surface.

9) Acrylic fibers: cross-sectional morphology: round, dumbbell-shaped or leaf-shaped; Longitudinal morphology: The surface is smooth or striated.

10) Chlorine fiber: cross-sectional morphology: nearly round; Longitudinal morphology: The surface is smooth.

11) Spandex fiber: cross-sectional form: irregular shape, round, potato-shaped; Longitudinal morphology: The surface is dark and deep, with unclear bony streaks.

12) Polyester, nylon, polypropylene fiber: cross-sectional form: round or special-shaped; Longitudinal Shape: Smooth.

13) Vinylon fiber: cross-sectional shape: waist round, leather core structure; Longitudinal shape: 1 2 grooves.

3.Fluorescence method: The fibers are irradiated with ultraviolet fluorescent lamps, and the fibers are identified according to the different luminescent properties of various fibers and the different fluorescence colors of the fibers.

The fluorescent colors of the various fibers are shown specifically:

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: white purple shade.

6) Bright viscose: pale yellow purple shade.

7) Polyester fiber: white light and blue sky light are very bright.

8) Vinylon has bright fibers: pale yellow purple shade.

1. Microscopic observation method.

Longitudinal and cross-sectional sections of fibers are made, and the longitudinal and transverse morphology of fibers are observed under a microscope to identify fibers according to differences in morphological characteristics.

Second, the combustion method.

During the combustion process of different fibers, flames, smoke, odors, residues, etc. will be different, so the types of fibers can be distinguished according to the characteristics of the fibers during and after combustion.

3. Reagent chromogenic method.

Due to the different structures of various fibers and the different coloring reactions of iodine and potassium iodide solutions, the fibers can be identified by observing the color and swelling of the fibers after the action of the reagent. This identification only applies to white fibers, which can only be tested after they have faded. Reagent Preparation:

Dissolve 20 grams of iodine in 100 ml of saturated potassium iodide solution, mix well, and then soak the fiber for 1 minute, and judge according to its color after full washing.

Fourth, dyeing method.

The dyeing method is used to identify fibers, mainly by using the different reactions of various fibers to the dye. There are two types of dyeing methods: cold dyeing and boiling dyeing.

Fifth, the dissolution method.

The dissolution method is the most effective method to identify various fibers, and the principle is to use the dissolution characteristics of various fibers in different chemical solvents and at different temperatures to determine their varieties.

The fibers to be identified can be put into a test tube, injected with a certain solvent, and stirred with a glass rod to observe the dissolution of the fibers. If the amount of fiber is very small, the specimen can also be placed in a concave surface with a concave glass slide, dripping with solvent, covering the glass slide, and observing directly under the microscope. When identifying fibers by dissolution method, the concentration of solvent and heating temperature should be strictly controlled, and the dissolution rate of fibers should be noted.

The use of the dissolution method requires an accurate understanding of the various fiber chemistries, and the inspection procedure is complex. The use of microscopy and combustion is intuitive, but the inspector must have extensive practical experience; The chromogenic and dyeing methods of reagents are complex and can be used in special situations.

1.Put it in water, not much water absorption for fibers (except silk) 2Fibers that emit a chemical odor by burning them with fire.

3.More practical, touch by hand, smooth for fiber (except silk) 4Curl them up with your hands, and be untruthful for fibers.

5.With the eye, the ones that are too bright are the fibers.

6.Put it in the sun, absorb heat too quickly for the fibers.

This life experience only, for your reference!

A simple way to identify natural fibers is the combustion method,1Cellulose fibers such as cotton and linen, which burn without change, burn rapidly, and have the smell of burning paper Fine and light black or off-white powder;

2.Protein fibers, such as hair, silk, etc., melt, curl and shrink when burning, burn slowly, sometimes self-extinguishing, the most obvious is the smell of burning hair, crunchy small black slag;

3.Polyester Shrink and melt Burning, melting, black smoke Burning, emitting black smoke, easy to extinguish No special odor Hard and bright gray-black balls.

The difference between the combustion of other chemical fibers is not very large, just observe more.

Plant fibers (natural cellulose fibers).

Seed fiber: cotton.

Bast fibers: hemp (flax, ramie, jute, hibiscus).

Advantages: hydrophilic fiber, fast moisture absorption, fast drying, durable, good hand feel. Good conformability, no hairballs, no static electricity problems.

Disadvantages: poor luster, lack of elasticity and resilience. After pinching by hand, there are creases that appear to be sensitive, and shrinkage will occur when it encounters water.

Man-made fiber (recycled fiber) bridge ruler touch.

Man-made cellulose fibers:

Viscose, cupra, fuqiang, acetate.

Artificial Protein Fiber:

Soybean fiber, peanut fiber, casein fiber.

Artificial inorganic fibers:

Fiberglass, metallic fiber.

Synthetic fibersPolyester fibers: Polyester polypropylene fibers: polypropylene fibers: Polypropylene polyamide fibers:

Nylon polyacrylonitrile fiber: acrylic polyvinyl alcohol fiber: vinylon polyvinyl chloride fiber:

Chlorine polyurethane fiber: spandex Other fibers: aramid.