How to Test the Density of Plastics

To test the density of plastics, refer to the following standards:

• GB/T 1033.1-2008: Immersion method, liquid pycnometer method, and titration method.
• GB/T 1033.2-2010: Density gradient column method.
• GB/T 1033.3-2010: Gas pycnometer method.

Common Plastic Densities

• PP: 0.89 – 0.93
• PP-T10: 0.95 – 0.99
• POM: 1.40 – 1.44
• PBT: 1.30 – 1.35
• ABS: 1.04 – 1.08
• PC+ABS: 1.10 – 1.16
• PA6: 1.12 – 1.16
• PS: 1.03 – 1.07
• PPS: 1.33 – 1.39
• (And many more for different plastic types.)

Methods to Change the Density of Plastics

1. Reducing the Density of Plastics
To reduce the density of plastics, the following methods can be used:

• Foaming Modification: This is the most effective way to lower plastic density. Plastic foam products can achieve a much lower density, with the minimum relative density reaching 10^-3.
• Adding Lightweight Fillers: This method can reduce density to around 0.4-0.5. Lightweight fillers include:
  • Glass hollow microspheres: Density 0.4-0.7.
  • Phenolic microbeads: Density 0.1.
  • Cork powder: Density 0.5.
  • Fiber powder (e.g., cotton scraps): Density 0.2-0.3.
  • Fruit shell crops (e.g., straw powder, peanut powder): Density 0.2-0.3.
• Blending Lightweight Resins: Adding lightweight resins like wood powder can further reduce density, but with limitations.

2. Increasing the Density of Plastics
To increase the density of plastics, heavy fillers and resins are used:

Adding Heavy Fillers:

• Metal powders (e.g., iron powder).
• Heavy mineral fillers.

Blending Heavy Resins:

• Resins like PTFE, PPS, and POM can be blended with lighter resins to increase density, but the improvement is typically limited to around 50%.