Firstly, there is a difference between the hardness of both materials. Polyethylene (PE) is tough yet light, with good resistance to impacts and abrasions. On the other hand, Polypropylene is harder and can be used for mechanical and structural applications.
Secondly, there is a difference between the stiffness of Polyethylene and Polypropylene. Polypropylene is stiffer and more chemical-resistant and scratch-resistant, while still being very tough. Polypropylene is known for its excellent chemical resistance in corrosive environments, as it is rugged and unusually resistant to many chemical solvents, bases and acids.
Summary of Properties:
|Material||Hardness||Stiffness||UV Resistance||Chemical Resistance||Toughness||Impact Resistance||Temperature Resistant||Price|
PE: Toys, films, Pipes, Tubes, Containers, bottles
PP: Drinking/milk bottles, Beach’s chair; Swimming pool’s pumps, Hard cover luggage, Car bumper