Question: what is the difference between high density polyethylene and polypropylene?
Answer: High Density Polyethylene is known for it's big strength-to-density ratio. The density of HDPE can range from 0.93 to 0.97 g/cm³. HDPE can be more rigid as a result. polypropylene, because of its lower density is used for molding parts with lower weight and more parts of a certain mass of plastic can be produced.