Acoustic Properties of Polymers

1
Acoustic Properties of Polymers

• By
• MO Robles
• June 12, 2000

2
Motivation

• Personal Experiences
• Studying sound effects on polymers
• Using the acoustic properties in daily life

3
Theory

• Absorption Properties
• How polymers dampen sound
• Real world uses
• Reflective Properties
• How polymers reflect sound
• Real world uses

4
Dampening Properties

• Theory
• Light polymers
• Want resonance within polymer network
• High elastic modulus
• Equations follow ones used in class (i.e.
  Maxwell)

5
Dampening Polymers

• Earplugs polyurethane
• Wall Composite polyurethane

6
Reflective Properties

• Theory
• Want heavy polymers
• (little or no resonance within polymer network)
• Low elastic modulus
• Equations follow ones used in class (i.e.
  Maxwell)
• Example MDF board

7
Reflective Polymers

• Sensitivity issues
• Desire a uniform polymer
• Example Polypropylene

8
State of the Art

• Sound Dampening
• Earplugs 30-35 NRR
• Drawbacks not used often, not frequency
  selective
• Sound Reflecting
• Strong composite construction MDF
• Drawbacks Heavy, expensive

9
Future Possibilities

• Dampening
• Cheaper material
• Sound selective polymers
• Reflecting
• Cheaper material
• Stronger polymer mixtures with less distortion