Chemistry

Polymer materials

Polymer materials


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Polypropylene (PP)

Polypropylene is a thermoplastic that is closely related to hard PE and is used, among other things, to manufacture injection molded parts, fibers, thermoformed parts and semi-finished products. Coffee machines and kettles are usually made of PP.

In contrast to hard PE, PP is characterized by greater hardness and rigidity.

Polypropylene has excellent resistance to acids, alkalis and polar organic solvents. It is practically non-staining, abrasion-resistant and has good tensile strengths. PP is characterized by low moisture absorption.

Fabrics made from polypropylene fibers are therefore used:

  • in the construction industry
  • in electrical insulation
  • as a precursor fabric for equipment suppliers
  • in gas filtration
  • in wet filtration
  • as cold protection fabric
  • as a coating carrier

Most synthetic carpets are made of PP fibers and PP is increasingly used for sportswear.

The starting material for the production of polypropylene is propene:

The average molar mass of technical polypropylene grades is 150,000 to 600,000 g / mol. In addition to molar mass distribution and isotaxy, this plays an outstanding role for the processing and usage properties of polypropylene.

Chemical properties

PP has good chemical resistance.

Thermal properties

Use in the temperature range below 0 ° C is not advisable for PP, as this can lead to embrittlement. The permanent heat resistance is up to + 100 ° C.

PP is the hardest of the polyolefin polymers and retains this property even at temperatures above 100 ° C. It is extremely friction-resistant and heat-resistant, has excellent dielectric properties, insulates very well and also has a special flexural strength (10 million bends). It is very resistant to environmental influences such as stress-related cracks. Only very strong oxidizing chemicals can crack. However, PP ages in UV light and is therefore mixed with 2.0 to 2.5% graphite. If, however, transparency is required, stabilizers must be used instead of graphite.


Video: Μπορούμε να ψήσουμε άλλα υλικά με τον πολυμερή πηλό; (July 2022).


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