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Thermoplastic Polymers
Thermoplastic polymers are commonly regarded as “plastics”. Thermoplastic polymers return to their original physical structure when cooled after melting. They are subgrouped into amorphous and semi-crystalline. The amount of crystalline contained depends on the original molecules and the thermal history of the polymer. Amorphous polymers are often transparent and semi-crystalline polymers are opaque. Amorphous polymers melt over a wide temperature range contrary to semi-crystalline polymers that have a distinct melting temperature.
PE (PolyEthylene)
PE is categorised by the density of the polymer, LDPE (low density), MDPE (medium density) and HDPE (high density). A higher crystallinity will produce a higher density, higher melt temperature, higher strength, and a lower permeability to gases and moisture. Polyethylene is a relatively inexpensive polymer that is widely used in medical applications.
- Low friction properties.
- Good chemical resistance.
- Service temperature up to +100º C (HDPE).
PP (PolyPropylene)
PP is a semi-crystalline polymer with wide versatility. PP is rather rigid and is frequently used when slightly better mechanical characteristics than HPDE are required.
- High fatigue resistance.
- Good chemical resistance.
- Service temperature up to +100º C.
EVA (EthyleneVinylAcetate), EMA (EthyleneMethylAcrylate), EBA EthyleneButylAcrylate)
Copolymers of ethylene and polar monomers (vinylacetate, methylacrylate or butylacrylate), are used to produce materials with various properties of stickiness, toughness and impact resistance.
- Flexible.
- High impact resistance.
- High toughness.
PA (Polyamide)
PA is a group of semi-crystalline thermoplastics, often referred to as Nylon®. The number of carbon atoms between the functional amid groups in PA produces different properties of this polymer with names such as PA6, PA11 and PA12 indicating these numbers. Absorption of water decreases with increasing numbers of carbon atoms.
- High strength, stiffness and hardness.
- Good wear resistance
- Service temperature up to +150ºC.
POM (PolyOxiMethylen)
POM is a highly crystalline polymer commonly named “acetal”. POM is a very hard, strong, dimension stable, opaque polymer, which is an effect of the high crystallinity.
- Low friction properties.
- High strength and hardness.
- High wear resistance.
- Low absorption and permeability of water.
PET (PolyEthyleneTerephtalate), PBT (PolyButyleneTerephthalate)
PET and PBT are two of the most commonly used polyesters. PET has a slow crystallisation process compared to all other polymers. PBT is more flexible and tougher than PET.
- High strength and hardness.
- High dimension stability.
- Good chemical resistance.
PC (PolyCarbonate)
PC is a polyester of carbonic acid that has an amorphous structure to provide transparency. PC is used for its toughness and strength.
- High strength and toughness.
- Good transparency.
- High dimension stability.
- Extreme impact resistance
For more information about properties of different themoplastic materials, see
 Summary_Properties.pdf
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