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Thermoplastics Classification
Oct 11, 2017

Amorphous thermoplastic polymers

In amorphous thermoplastic polymers, the molecule chains are completely chaotically arranged and tangled with each other like the threads of a cotton wool pad. This amorphous structure means that these materials cannot be subjected to loads above the glass transition point. This material group is further characterized by the following properties:

Structure of amorphous thermoplastic polymers
  • mostly transparent or translucent

  • low tendency to creep

  • good dimensional stability

  • low tendency to warp

  • tendency to brittleness

  • low chemical resistance

  • sensitive to stress cracking
     

Amorphous plastics have a low tendency to warp and are consequently very suitable for use in housing components.

Semi-crystalline thermoplastics

The macromolecules of semi-crystalline thermoplastic polymers form a crystalline structure in some areas. Plastics with semi-crystalline structures are generally opaque, as the crystalline areas scatter the light. Due to the crystalline areas, the materials are extremely tough (strong intermolecular forces) and are capable of withstanding mechanical loads also above the glass transition temperature. The semi-crystalline thermoplastic polymers can be characterized by the following properties.

Structure of semi-crystalline thermoplastics
  • translucent or opaque

  • good fatigue resistance

  • tendency to toughness

  • good chemical resistance

  • good sliding characteristics

  • wear resistant

  • glass transition

  • degree of crystallinity
     

Due to their tough-hard behaviour, semi-crystalline plastics are particularly suited for components subject to mechanical wear and for sliding materials.