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Plastic Properties of Polypropylene (PP)
Polypropylene (PP), a polymer prepared catalytically from propylene
which differs from HDPE by having an isostatic replacement of a hydrogen
atom by a methyl group on alternate carbon atoms in the main chain.
Although largely unreactive chemically the presence of the methyl groups
makes Polypropylene slightly more susceptible to attack by strong
oxidizing agents than HDPE. A major advantage is Polypropylene's higher
temperature resistance, this makes PP particularly suitable for items
such as trays, funnels, pails, bottles, carboys and instrument jars that
have to be sterilized frequently for use in a clinical environment.
Polypropylene is a translucent material with excellent mechanical
properties and it has gradually replaced the polyethylenes for many
purposes.
PP Resistance: Excellent resistance (no attack) to dilute and
concentrated Acids, Alcohols, Bases and Mineral Oils. Good resistance (minor
attack) to Aldehydes, Esters, Aliphatic Hydrocarbons, Ketones and
Vegetable Oils. Limited resistance (moderate attack and suitable for
short term use only) to Aromatic and Halogenated Hydrocarbons and
Oxidizing Agents.
Polypropylene Quick Facts:
Maximum Temperature: 275°F
135°C
Minimum Temperature: 32°F 0°C
Autoclavable: Yes
Melting Point: 338°F 170°C
Tensile Strength: 4,500 psi
Hardness: R95
UV Resistance: Poor
Translucent
Rigid
Specific Gravity: 0.90
Polypropylene Fabrication: Great chemical resistance makes
Polypropylene a popular choice for plating and chemical tanks, as well
as laboratory cabinetry and semi-conductor bench tops. This material
machines well and is available in many profiles.
Propylene is autoclaveable for usage in biohazardous environments. Other
uses include fittings and connectors, storage containers, sinks, and
hoods. The best joining method is hot air or nitrogen welding. Can be
mechanically joined with screws or rivets. Ultrasonic inserts work well.
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