It has been used to decorate jars and other objects since ancient times, but fiberglass was invented at the 1893 Columbian Exposition when the Oenslipp Glass Company heated one end of a glass rod, pulled it out, and wound it around a spinning drum to make it into a fiber. Fiber is shaped by mechanically stretching molten glass, blowing it with air or water vapor, or blowing it around by centrifugal force. Depending on the application, there are long and short fibers (glass wool and glass wool), and the production of long fibers is often done by pushing the molten glass in a platinum pot through a small hole in the bottom of the pot. The properties of glass fiber are that it can withstand high temperatures and does not burn. It is non-absorbent and has low moisture absorption. It is academically durable and does not corrode. High strength, especially tensile strength. Low elongation. Large electrical insulation. Low wear resistance, brittle and easy to break. The specific gravity is 2.2 times that of nylon and 1.7 times that of cotton. Mats made of it have good heat and sound insulation.
The properties and applications of glass fibers are classified as A glass, C glass, E glass, S glass, etc. according to the raw material composition.
A glass, commonly known as bottle glass, is a high alkali glass with good chemical resistance. The most common glass fiber is E-glass, which has a low alkali composition and is used for electrical insulation purposes. Currently, most fiberglass composite products are made of E glass fiber. C glass is used when academic corrosion resistance is required, and S glass is used when high tensile strength is required. S glass is made of high-purity silica with impurities removed from E glass, can be used at high temperatures, and has a tensile strength about 40% higher than E glass. Therefore, most of the glass fibers used in Advanced Composite Materials (ACM) are S glass.
| E-Class | C-Glass | S-Glass | |
| Diameter(㎛) | 10 | – | 10 |
| Density(g/㎤) | 2.54 | 2.49 | 2.48 |
| Tensile Strength(㎬) | 3.43 | 3.3 | 4.6 |
| Modulus of Elasticity(㎬) | 73 | 69 | 86 |
| Elongation(%) | 4.8 | 4.9 | 5.7 |
| Specific Heat | 0.197 | 0.212 | 0.176 |
| Thermal conductivity(W/mㆍK) | 1.04 | – | 1.05 |
| Coefficient of Thermal Expansion(10-6lk) | 5.0 | 7.2 | 5.6 |
| Softening point(K) | 1.113 | 1.023 | 1.243 |
| Classification | E-Class(%) | C-Glass(%) | S-Glass(%) |
| SiO2 | 55.2 | 65.0 | 65.0 |
| Al2O3 | 8.0 | 4.0 | 25.0 |
| CaO | 18.7 | 14.0 | – |
| MgO | 4.6 | 3.0 | 10.0 |
| Na2O | 0.3 | 8.5 | 0.3 |
| K2O | 0.2 | – | – |
| B2O | 7.3 | 5.0 | – |