PE vs PP

Thinking about plastics that are lighter than Polyethylene or in the same density range, Polypropylene comes to mind.
Trying to think about their similarities and differences; both are inert.
PE...
is more flexible,
accumulates less static charge,
is far less stiff
is costlier

Now some figures:

Property	HDPE	LDPE	PP
Tensile Strength	0.20 - 0.40 N/mm²	0.20 - 0.40 N/mm²	0.95 - 1.30 N/mm²
Notched Impact Strength	no break Kj/m²	no break Kj/m²	3.0 - 30.0 Kj/m²
Thermal Coefficient of expansion	100 - 220 x 10-6	100 - 220 x 10-6	100 - 150 x 10-6
Max Cont Use Temp	65 °C	65 °C	80 °C

PP possess higher tensile strength.
However PP is far less wear and weather resistant.