Structure⁻Properties Relations for Polyamide 6, Part 1: Influence of the Thermal History during Compression Moulding...

Area of Science:

• Materials Science
• Polymer Science
• Mechanical Engineering

Background:

• Polyamide 6 (PA6) properties are sensitive to processing and environmental conditions.
• Understanding deformation and failure kinetics is crucial for material design and application.
• Thermal history and hydration significantly influence polymer structure and performance.

Purpose of the Study:

• To investigate the deformation and failure kinetics of PA6 under varying thermal histories, temperatures, and relative humidities.
• To characterize the effects of thermal history and hydration on PA6 structure and glass transition temperature.
• To establish a relationship between PA6 structural evolution and its mechanical behavior.

Main Methods:

• PA6 samples were prepared with different thermal histories (quiescent condition, multiple cooling procedures).
• Mechanical properties were assessed using tensile and creep tests at various temperatures and relative humidities.
• Structural characterization and glass transition temperature determination were performed.

Main Results:

• Deformation and failure kinetics were found to be dependent on temperature and relative humidity.
• Thermal history and hydration altered the structure and glass transition temperature of PA6.
• The Ree-Eyring equation and critical strain concept effectively described the experimental mechanical data.

Conclusions:

• A correlation was established between the Eyring theory parameters (rate factors) and the average lamellar thickness of PA6.
• The study provides insights into structure-property relationships in PA6, linking molecular structure to macroscopic mechanical response.
• This research contributes to a better predictive model for PA6 material behavior in diverse environments.