Glass is an extremely versatile material, of which there are numerous variations, obtained thanks to the addition of certain elements that modify its chemical-physical properties. In common parlance this term is used to refer to glasses consisting mainly of silicon oxide, used in realization of fixtures, containers and glasses and in the manufacture of decorative elements.
There is another type of glass that must be remembered in light of its applicative ductility: borosilicate glass, consisting mainly of silica and diboron trioxide.
What is this?
Borosilicate glass, also known under the trade name of Pyrex, is a sturdy material, used for its qualities of resistance to thermal changes and for its low expansion coefficient. It is obtained by replacing the alkaline oxides with boron oxide in the glass lattice of the silica. When boron oxide enters the silica lattice it weakens its structure, due to the presence of trivalent planar boron atoms, and lowers its softening point.
The chemistry of borosilicate glass
Specifically, borosilicate glass is created by combining and melting boric dioxide (or diboron trioxide, as noted above), silica sand, sodium carbonate and alumina. The composition of low expansion borosilicate glass is approximately 80% silica, 13% boric anhydride, 4% sodium or potassium oxide and 2-3% aluminum oxide. The peculiarity of this glass lies precisely in its composition, similar to that of ordinary glass, from which lead is however excluded. Despite the absence of this element, the glass does not lose its brightness or transparency.
History
This type of glass is more difficult to make than the traditional one, due to the high melting temperature; but it is cheaper to produce.
Borosilicate glass was developed by the German chemist and entrepreneur Friedrich Otto Schott at the end of the XNUMXth century in Jena, the city from which this type of glass originally took its name, providing a valuable solution for scientific and technological applications, particularly in the chemical sector.
In 1915, the US company Corning Glass Works began marketing its borosilicate glass products under the Pyrex brand.
A range of benefits
Borosilicate glass satisfies a wide variety of applications, thanks to its advantageous characteristics, including:
- la heat resistance and sudden changes in temperature;
- un low expansion coefficient;
- dowries of chemical inertness e transparency.
And then totally hygienic: as it is not porous, it does not retain bacteria. Easy to clean, great for food preservation since it does not alter the taste of food and does not contain substances that are potentially harmful to humans, as it is made up of natural components. Finally, it is completely reusable, sterilizable and 100% recyclable.
Applications
But let's get back to its applications now. Borosilicate glass guarantees a wide variety of uses, ranging from kitchen tools to laboratory equipment; but also high quality products, such as medical devices and devices for the aerospace sector.
Almost all modern laboratory glassware it is made of borosilicate glass, thanks to its chemical and thermal resistance and good optical transparency.
Furthermore, borosilicate is widely used in of medical devices implantable, such as eye implants, artificial hip joints, bone cements, dental composite materials and even in breast implants.
The semiconductor industry also requires this type of glass for the development of microelectromechanical systems (MEMS). While the optic focuses on the low coefficient of thermal expansion of borosilicate glasses to make components for reflection astronomical telescopes.
To learn about the different families of borosilicate glass and other applications click here.
Sources: wikipedia, tescomaonline.com
