Applications of Polycarbonates

Electronic components

Polycarbonate is mainly used for electronic applications that capitalize on its collective safety features. Being a good electrical insulator and having heat resistant and flame retardant properties, it is used in various products associated with electrical and telecommunications hardware. It also serves as dielectric in high stability capacitors.

Pros and Cones of Polycarbonates (Advantages and Disadvantages)

Pros (Advantages)

1. Excellent impact resistance and strength at low and high temperatures.
2. Available in visually clear grades.
3. Good heat strength, flame retardant, RoHS compliant, mould release, good lubricated, dimensional stability, good impact resistance, good process ability, good heat resistance and high viscosity.

Properties of Polycarbonates

• High Durability: Polycarbonate plastic is an extremely durable material. This makes it the material of choice where long product life and reliable performance are critical.
• Shatter Resistance: Polycarbonate is virtually unbreakable.

Synthesis of Polycarbonates

PC is most often synthesized from Bisphenol A and phosgene by a step-growth polymerization in which Cl- ions are eliminated every time the monomers react.

History of Polycarbonate Polymers

The discovery of Polycarbonate dates back to 1898 when Alfred Einhorn, a German chemist, observed the formation of an insoluble, infusible solid, while endeavouring to prepare cyclic carbonates by reacting hydroquinone with phosgene.

Applications/Uses of Aramid (Kevlar) Polymers

• Kevlar is five times stronger than steel, yet it is extremely lightweight. Kevlar does not rust or corrode and it absorbs vibrations readily. Kevlar is expensive because special precautions are necessary to handle the concentrated sulfuric acid used in its production.
• Kevlar breaks down when exposed to the ultraviolet rays in sunlight. Dry-cleaning agents bleach, and repeated washing can affect Kevlar negatively also. To protect against these problems, the layers of Kevlar in bullet-resistant vests have fabric coverings to prevent exposure to sunlight and moisture.

Properties of Aramid Fibers

Aromatic polyamides are characterized by high melt temperatures, excellent thermal stability and flame resistance, and poor solubility in many inorganic and organic solvents. An important aspect here is the effect of polymer composition on physical properties. This can be detected by comparing homopolymers vs. copolymers, unsubstituted vs. substituted polymers, and para- vs. meta-oriented polymers.

Synthesis of Aramid Polymers (Polymerization Process)

The world capacity of para-aramid production is estimated at about 41,000 tons/year in 2002 and increases each year by 5–10 %. In 2007 this means a total production capacity of around 55,000 tons/year.

History of Aramid Polymers

Aramids were first introduced in commercial applications in the early 1960s, with a meta-aramid fiber produced by DuPont as HT-1 and then under the trade name "Nomex". This fiber, which handles similarly to normal textile apparel fibers, is characterized by its excellent resistance to heat, as it neither melts nor ignites in normal levels of oxygen. It is used extensively in the production of protective apparel, air filtration, thermal and electrical insulation as well as a substitute for asbestos.

Aramid Definition – Federal Trade Commission

The Federal Trade Commission definition for aramid fiber is:
"A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polyamide in which at least 85% of the amide linkages, (-CO-NH-) are attached directly to two aromatic rings."

Applications/Uses of Acrylonitrile Butadiene Styrene (ABS) Polymers

• ABS plastic ground down to an average diameter of less than 1 micrometer is used as the colorant in some tattoo inks. Tattoo inks that use ABS are extremely vivid.
• ABS's light weight and ability to be injection molded and extruded make it useful in manufacturing products such as drain-waste-vent (DWV) pipe systems, musical instruments (recorders, plastic clarinets, and piano movements) and golf club heads (due to its good shock absorbance).

Advantages and Disadvantages of Acrylonitrile Butadiene Styrene (ABS) Polymers

PROS / ADVANTAGES OF (ABS) POLYMERS

Excellent impact resistance. It can have good appearance for cosmetic parts. Strength is moderate. Good resistance to acids and bases.

Properties of Acrylonitrile Butadiene Styrene (ABS) Polymers

The acrylonitrile, butadiene and styrene ratios along with two other factors are important in determining the properties of ABS polymers. First, it is not a homogeneous mixture and consists of a dispersed phase. Second, the dispersed phase always consists of both rubber and occlusions of the SAN matrix within the rubber. Its outstanding material qualities made ABS become one of the most popular plastics materials and an essential element in everyday life. Here are some general properties listed below of the ABS polymers…

Synthesis of Acrylonitrile Butadiene Styrene (ABS) Polymers

ABS is made by emulsion or continuous mass technique. Globally, the most important is the emulsion process. ABS can be processed by injection moldings or extrusion technique.

Acrylonitrile Butadiene Styrene (ABS) Polymers History

Acrylonitrile-Butadiene-Styrene has been available since the 1940's. In attempts to produce bulletproof plastic sheets during the last years of World War II, polymer systems were developed from special butadiene acrylonitrile copolymers and styrene acrylonitrile copolymers with high molecular masses. These materials have a high impact resistance on account of their low thermoplastic flow, but they can only processed using extruders. Semi-finished Products were the first parts to be made from ABS polymers and had dull or matt surfaces.