Effect of Conditioning on PU Foam Matrix Materials Properties

Area of Science:

• Materials Science
• Polymer Chemistry
• Mechanical Engineering

Background:

• Polyurethane (PU) foams are widely used in various applications.
• Understanding the aging behavior of PU foams is crucial for predicting their service life.
• Thermal-induced aging, particularly under humid conditions, can significantly alter material properties.

Purpose of the Study:

• To characterize the thermal-induced aging of soft polyurethane (PU) foams.
• To investigate the effects of relative humidity on the thermal and mechanical properties of PU foams.
• To evaluate the degradation mechanisms and their impact on material performance.

Main Methods:

• Thermal analysis (e.g., TGA, DSC).
• Mechanical testing: tensile, compression, and dynamic mechanical vibration testing.
• Non-destructive forced oscillations vibration-damping testing.

Main Results:

• Increased relative humidity initiates degradation processes in PU foams.
• Degradation leads to decreased mechanical stiffness, increased permanent deformation, and reduced Young's modulus.
• Vibration-damping testing and hardness measurements confirm the loss of elasticity and elastic mechanical performance.
• Conditioning under humid conditions results in a significant loss of thermal stability.

Conclusions:

• Relative humidity is a critical factor initiating the degradation of soft PU foams.
• The observed mechanical property changes are attributed to plasticization of the foam's matrix.
• The study highlights the importance of environmental factors in the long-term performance and durability of PU foams.