October 30, 2016

Introduction To Polypropylene (PP)

Polypropylene is a polymer plastic that is a member of the ‘polyolefin’ (polymers produced from alkenes) family. It is a highly versatile material that has many beneficial physical properties, and most importantly it is also recyclable.

In chemical terms, it is a linear hydrocarbon polymer, with little unsaturation. The addition of a methyl group on to the hydrocarbon chain can affect physical properties such as melting temperature.

A simple way to identify PP is using Near Infrared Radiation (NIR) techniques. It must be noted that this cannot work with darkly coloured plastics as dark colours wil absorb the radiation.

Properties and Applications of Polypropylene (PP)

Polypropylene is an extremely versatile material and as such can be used for a wide range of applications. PP is tough and yet flexible and classed as semi-rigid. It is extremely resistant to heat, chemicals and fatigue. Furthermore, it is translucent and has an integral hinge property.

PP has a wide range of uses, including:

  • Clear film packaging
  • Carpet fibres
  • Housewares
  • Rope
  • Labelling
  • Banknotes
  • Stationary
  • Reusable containers
  • Loudspeakers
  • Automotive components
  • Laboratory equipment
  • Thermal underwear

After a dip in global demand during the global recession, polypropylene is in high demand once more.


Sandbags made from polypropylene, one of the many applications of this flexible polymer. Image Credit:

Recycling of Polypropylene

To make recycling of polypropylene economically viable, several factors must be taken into account. Most importantly, the difficultly and expense of the recycling process needs to be reduced. This process includes sorting, collecting, cleaning and reprocessing.

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