*2.3.1. Glass*

Glass fiber is an inorganic nonmetallic man-made fiber. Generally, the glass is defined as the frozen state of a supercooled and thus solidified liquid. It results from the suppression of the crystallization of melt. Initial materials for producing glass are different mineral substances largely found in nature (quartz sand, chalk, dolomite, feldspar, and others).

Glass fibers are produced from different compositions (%) of glass (Table 3).


**Table 3.** Glass fiber composition

Nonwovens of glass fibers are classified as follows:


In general, textile glass fibers have a high tenacity at a low elongation combined with extremely low density. This results in favorable tenacity or modulus values relative to their weight. Glass fiber is brittle, but in drawing very thin fibers (with a diameter of several micron) from molten glass, a fibrous material is obtained, having a flexibility sufficient for textile processing and utilization as a finished product.

Glass fiber mats are excellent heat and noise insulation materials. They are capable of with‐ standing temperatures above 150°C. Textile glass as a mineral material is naturally inflamma‐ ble and does not release steam or poisonous gases when subjected to heat.

Glass fabrics are highly efficacious for filtering various liquids; filters of glass fibers used for filtering corrosive chemical reagents have a life 10 or 15 times longer than those made of usual materials (cotton, metal web etc). Glass staple fibers are used for the reinforcement of plastics and building materials for insulation and so forth [32].
