PP, polypropylene,is a translucent, semi-crystalline thermoplastic.
PS, polystyrene, environmental protection non-toxic, plasticity is very good, ductile poor brittle.
How to distinguish between PP and PS materials?
Firstly, the difference of the sound: PS material is more hard, so the sound of percussion sounds more crisp. and PP material toughness is good, hardness is not enough, so the sound is more boring.
Secondly, the appearance of the difference: PS can be very transparent, PP most highly transparent, but it looks still sticky, like the feeling of grinding glass.
Thirdly, the difference in texture: toughness of PP is good, and PS is more rigid, feeling is that PP is soft comparing with PS.