1. Density:
PP is less dense than all synthetic resins, only 0.90-0.91g/cm3,
which is about 60% of the density of PVC. This means that more
products of the same volume can be produced from the same weight of
raw materials.
2. Mechanical
properties: PP has good tensile strength and rigidity, but poor
impact strength, especially at low temperature. In addition, if
there is orientation or stress in the forming process, the impact
strength will also be significantly reduced. Although the impact
strength is poor, its mechanical properties can compete with
engineering plastics with higher cost in many fields after
modification such as filling or strengthening.
3. Surface
hardness: The surface hardness of PP is lower than that of PE in
five kinds of general plastics. When the crystallinity is high, the
hardness increases correspondingly, but it is still lower than PVC,
PS, ABS and so on.
4. Thermal
properties: Among the five general plastics, PP has better heat
resistance. PP plastic products can work for a long time at 100 C,
without external force, PP products will not deform when heated to
150 C. After using nucleating agent to improve the crystalline
state of PP, the heat resistance of PP can be further improved. It
can even be used to make utensils for heating food in microwave
oven.
