E-glass is also known as alkali-free glass, 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 insulation, and It is also widely used in the production of glass fiber reinforced plastic. Its disadvantage is that it is easy attacked by inorganic acid. So it is not suitable for acidic environment. The E-glass composition is roughly in the follow range:
Density (g/cm3): 2.51~2.61
Tensile strength (MPa): 2187
Tensile elastic modulus (MPa): 75460
Dielectric constant (at 22C, 10Hz): 6.1~6.7
Acid resistance: 39%
C-glass is known as medium-alkali glass. It’s characterized by chemical resistance, especially acid resistance, which is better than alkali-free glass. However, its electrical properties are poor, and its mechanical strength is 10 ~ 20% lower than that of alkali-free glass.Usually a medium-alkali glass fiber out of China contains a certain amount of B2O3, while China's medium-alkali glass fiber is completely free of boron. In foreign countries, medium alkali glass is only used to produce corrosion-resistant glass fiber products, such as glass fiber surface felt. And it is also used to strengthen asphalt roofing materials. But in China, alkali glass fiber accounts for 60% of glass fiber production. It is widely used in the reinforcement of glass fiber reinforced plastic and the production of filter fabrics and bandaging fabrics. Because its price is lower than that of alkali-free glass fiber, it has strong competitiveness.