Polycarbonate

The polycarbonate is a group of thermoplastics , easy to work, molding and thermoforming, and is widely used in modern manufacturing. The name polycarbonate is because it is a polymer that has functional groups linked by carbonate groups in a long molecular chain.

Summary

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  • 1 Definition
  • 2 uses
    • 1 Transparent and translucent ceilings, domes and skylights
    • 2 Guards of industrial machinery
    • 3 Advertising industry
  • 3 Advantages
  • 4 Disadvantages
  • 5 History
    • 1 Structure and Properties
    • 2 Impact resistance and hardness
  • 6 Electrical, Mechanical and Chemical Properties
  • 7 Sources

Definition

Polycarbonate is a thermoplastic with very interesting properties in terms of impact resistance, heat resistance and optical transparency, in such a way that the material has strongly penetrated the market in a variety of functions. In sheet form it has three common presentations:

  • solid sheet – also called monolithic
  • cellular lamina -also known as alveolar
  • solid corrugated sheet

Applications

Its high resistance to impact and its extraordinary optical properties have earned this thermoplastic an important position in the market for certain specific uses:

Transparent and translucent ceilings, domes and skylights

In this application the cellular sheet is used above all for its lightness and for the reduced cost that comes off it.

Industrial machinery guards

Solid polycarbonate is the right material for this application, since its impact resistance is approximately 200 times greater than that of a comparable acrylic sheet in terms of size and thickness.

Advertising industry

Solid polycarbonate is increasingly used for commercials.

Any other application that requires the very special physical properties of this material.

Advantage

  • Extremely high impact resistance
  • Great transparency
  • High strength and stiffness
  • High resistance to thermal deformation
  • High dimensional stability, i.e. high creep resistance
  • Good electrical insulation properties
  • High resistance to weathering, with protection against ultraviolet rays

Disadvantages

  • Medium resistance to chemical substances
  • Notch sensitivity and susceptibility to stress cracks
  • Hydrolysis sensitivity

History

It was discovered in 1928 but it was until 1952 , by Bayer and 1953 , by GE that the production processes were developed. Both companies patented the material almost simultaneously, Bayer 8 days before GE. In 1959 and 1960 , respectively, these two companies went into production.

The material took time to be placed on the market. In 1982 compact discs – made of polycarbonate – came out and from the 1980s it began to be used for water bottles, replacing glass .

Structure and Properties

It is a polymer formed from Bisphenol-A molecules, linked with carbonate groups.

Its impact resistance, which is of the order of 200 times greater than that of glass, is the property that allows it to be produced in honeycomb sheets, also known as “cellular”, with walls of reduced thickness and consequently at relatively low cost. In this presentation the material is used in the construction of skylights and domes, having largely displaced acrylic .

Impact resistance and hardness

There is some confusion between the concepts impact resistance and hardness. In fact polycarbonate is a relatively soft material and it is precisely this property that gives it its impact resistance.

Because of this confusion, this material is often chosen for a certain application knowing its impact resistance, when really what was required was a relatively hard material.

Electrical, Mechanical and Chemical Properties

  • Dielectric Constant @ 1MHz 2.9
  • Dissipation Factor at 1 MHz 0.01
  • Dielectric Strength (kV mm-1) 15-67
  • Surface Resistivity (Ohm / sq) (kV mm-1) 1015
  • Volume Resistivity (Ohmcm) 1014-1016 / td>

 

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