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What are the characteristics of glass fiber?

2022-09-23 Page view : 3 views

Glass fiber (original name in English: glass fiber or fiberglass) is an inorganic non-metallic material with excellent performance. Brittle, poor wear resistance. It is made of glass balls or waste glass through high temperature melting, wire drawing, winding, weaving and other processes. 1/20-1/5 of the filaments, each bundle of fiber strands is composed of hundreds or even thousands of monofilaments. Glass fibers are usually used as reinforcing materials in composite materials, electrical insulating materials and thermal insulation materials, circuit substrates and other fields of the national economy.

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Glass is generally regarded as a hard and fragile object, and it is not suitable for use as a structural material. However, if it is drawn into filaments, its strength is greatly increased and it has flexibility. Therefore, it can finally become an excellent structural material after being given a shape with resin.fiberglass increase in strength as their diameter decreases.

Features introduction

Raw material and its application fiberglass has higher temperature resistance, non-combustibility, corrosion resistance, good heat insulation and sound insulation (especially glass wool) than organic fiber, high tensile strength and good electrical insulation (such as alkali-free glass fiber). But it is brittle and has poor wear resistance. Glass fiber is mainly used as electrical insulating material, industrial filter material, anti-corrosion, moisture-proof, heat-insulating, sound-insulating, shock-absorbing material. It can also be used as a reinforcing material to make reinforced plastics (see color pictures) or reinforced rubber, reinforced gypsum and reinforced cement and other products. Coating fiberglass with organic materials can improve their flexibility and can be used to make packaging cloths, window screens, wall coverings, covering cloths, protective clothing and electrical and sound insulation materials. As a reinforcing material, glass fiber has the following characteristics, which make the use of glass fiber far more extensive than other types of fibers, and the development speed is also far ahead. Its characteristics are listed as follows: (1) High tensile strength, small elongation (3% ). (2) High elastic coefficient and good rigidity. (3) The amount of elongation within the elastic limit is large and the tensile strength is high, so the absorption of impact energy is large. (4) It is an inorganic fiber, which is non-flammable and has good chemical resistance. (5) Low water absorption. (6) Scale stability and heat resistance are good. (7) It has good processability and can be made into different forms of products such as strands, bundles, felts, and woven fabrics. (8) Transparent through light. (9) The development of a surface treatment agent with good adhesion to resin has been completed. (10) The price is cheap. (11) It is not easy to burn and can be melted into glass beads at high temperature.

main ingredient

Its main components are silicon dioxide, aluminum oxide, calcium oxide, boron oxide, magnesium oxide, sodium oxide, etc. According to the alkali content in the glass, it can be divided into alkali-free glass fiber (sodium oxide 0% to 2%, belonging to aluminum Borosilicate glass), medium alkali glass fiber (8% to 12% sodium oxide, belonging to soda lime silicate glass with or without boron) and high alkali glass fiber (more than 13% sodium oxide, belonging to soda lime silicate glass).

Glass fiber can be divided into continuous fiber, fixed-length fiber and glass wool according to shape and length; according to glass composition, it can be divided into alkali-free, chemical-resistant, high-alkali, medium-alkali, high-strength, high-elastic-modulus and alkali-resistant glass fiber, etc. The main raw materials for producing glass fiber are: quartz sand, alumina and pyrophyllite, limestone, dolomite, boric acid, soda ash, mirabilite, fluorite, etc. The production methods are roughly divided into two categories: one is to directly make molten glass into fibers; the other is to first make molten glass into glass balls or rods with a diameter of 20 mm, and then heat and remelt them in various ways to make glass balls or rods with a diameter of 3 to 3 mm. 80μm very fine fibers. The infinitely long fibers drawn by the mechanical drawing method of platinum alloy plates are called continuous glass fibers(G3 G4 Fiberglass manufacturer ), commonly known as long fibers. Discontinuous fibers made by rollers or air flow are called fixed-length glass fibers, commonly known as short fibers. Thin, short, flocculent fibers made by centrifugal force or high-speed airflow are called glass wool. Glass fibers can be processed into various forms of products, such as yarn, roving, chopped strands, cloth, tape, felt, plate, tube, etc. According to the composition, properties and uses, glass fibers are divided into different grades. According to the standard grade regulations (see table), E-grade glass fiber is the most widely used and is widely used in electrical insulation materials; S-grade is a special fiber, although the output is small, but it is very important, because of its super strength, it is mainly used for military defense, such as Bulletproof boxes, etc.; Grade C is more chemical resistant than Grade E, and is used for battery separators and chemical poison filters; Grade A is alkaline glass fiber, which is used for the production of reinforcing materials. The glass used in the production of glass fibers is different from the glass used in other glass products. The glass compositions for fibers that have been commercialized internationally are as follows:

E-glass

Also known as alkali-free glass, it is a borosilicate glass. At present, it is the most widely used glass component for glass fiber. It has good electrical insulation and mechanical properties. It is widely used in the production of glass fiber for electrical insulation and is also widely used in the production of glass fiber for FRP. Inorganic acid attack, so it is not suitable for use in acidic environment.

C-glass

Also known as medium-alkali glass, its characteristics are chemical resistance, especially acid resistance, which is better than that of alkali-free glass, but its electrical properties are poor, and its mechanical strength is 10% to 20% lower than that of alkali-free glass fiber. Usually foreign medium-alkali glass fiber contains a certain amount of glass. The amount of boron trioxide, and my country’s medium alkali glass fiber is completely free of boron. In foreign countries, medium-alkali glass fiber is only used to produce corrosion-resistant glass fiber products, such as the production of glass fiber surface mats, etc., and also used to strengthen asphalt roofing materials, but in my country, medium-alkali glass fiber accounts for more than half of the glass fiber output. (60%), widely used in the reinforcement of FRP and the production of filter fabrics, wrapping fabrics, etc., because its price is lower than that of alkali-free glass fiber and has strong competitiveness.

high strength glass fiber

It is characterized by high strength and high modulus. Its single fiber tensile strength is 2800MPa, which is about 25% higher than that of alkali-free glass fiber, and its elastic modulus is 86000MPa, which is higher than the strength of E-glass fiber. The FRP products produced with them are mostly used in military industry, space, bulletproof armor and sports equipment. However, due to the high price, it cannot be popularized for civilian use at present, and the world’s output is only about a few thousand tons.

AR fiberglass

Also known as alkali-resistant glass fiber, it is mainly developed to strengthen cement.

A glass

Also known as high alkali glass, it is a typical sodium silicate glass, which is rarely used in the production of glass fibers due to its poor water resistance.

E-CR glass

It is an improved boron-free and alkali-free glass used to produce glass fiber with good acid and water resistance. New varieties developed for underground pipelines, storage tanks, etc.

D glass

Also known as low dielectric glass, it is used to produce low dielectric glass fibers with good dielectric strength. In addition to the above glass fiber components, a new type of alkali-free glass fiber has appeared in recent years. It does not contain boron at all, thereby reducing environmental pollution, but its electrical insulating properties and mechanical properties are similar to traditional E glass. In addition, there is a glass fiber with double glass composition, which has been used in the production of glass wool, and it is also said to have potential in the field of glass fiber reinforced plastics. In addition, there is fluorine-free glass fiber, which is an improved alkali-free glass fiber developed for environmental protection requirements.

The tensile strength of glass fiber is high and the elongation is small (3%). The test method standards are: GB/T14338-1993 Test Method for Crimping of Synthetic Short Fibers, GB/T 15232-1994 Determination of Tensile Breaking Strength of Textile Glass Fiber Mats , GB/7689.5 Determination of Tensile Strength and Elongation at Break of Glass Fiber Determination of tensile strength at break and elongation at break of fibers, etc. The single fiber strength and elongation performance test should use a high-strength and high-modulus fiber strength tester capable of testing glass fibers