Characterization of Polysulfone and Polyethersulfone with GPC/SEC

Significance of the Topic

The molecular weight distribution of high-performance polymers such as polysulfone (PSU) and polyethersulfone (PES) critically determines their thermal stability, mechanical strength and chemical resistance. Accurate characterization of these distributions by GPC/SEC supports the development of membranes and flame-retardant materials used in demanding applications.

Objectives and Overview of the Study

This study aimed to determine the molar mass distribution profiles of PSU and PES using Gel Permeation/Size Exclusion Chromatography. A comparison of the two polymers under identical conditions provided insights into production consistency and material performance.

Methodology and Instrumentation Used

GPC/SEC analysis was performed under isocratic conditions with dimethylacetamide containing lithium bromide as the mobile phase at elevated temperature. Key instrument components and parameters included:

• Isocratic pump delivering 1 mL/min of DMAc with 5 g/L LiBr
• Autosampler with 50 µL injection volume
• GRAM high-MW column set (10 µm guard + 100 Å + two 3000 Å columns) at 70 °C
• Sample concentration of 2–3 mg/mL
• Calibration against PMMA standards (ReadyCal-Kit)
• Refractive index detector for concentration-sensitive response
• Data processed using dedicated chromatography software

Main Results and Discussion

Overlay traces of PSU and PES revealed broad, comparable molar mass distributions starting from low molecular weight fractions. The selected GRAM column combination exhibited sufficient resolution across the distribution, enabling clear differentiation of polymer chain lengths. Consistency between samples demonstrated robust method performance and suitability for routine analysis.

Benefits and Practical Applications

Accurate GPC/SEC profiling of PSU and PES offers:

• Quality control of membrane materials and industrial components
• Correlation of processing conditions with final material properties
• Optimization of polymer synthesis for targeted performance

Future Trends and Opportunities

Advancements in detector technology (e.g., multi-angle light scattering) and chromatographic columns will further refine molar mass accuracy. Integration with hyphenated techniques and high-throughput methods is poised to accelerate polymer research and production optimization.

Conclusion

This application demonstrates that GPC/SEC with GRAM high-MW columns and DMAc/LiBr mobile phase reliably characterizes PSU and PES molar mass distributions. The approach provides essential data for material development and quality assurance in high-performance polymer applications.

References

1. Mark, J. E. Polymer Data Handbook; Oxford University Press, Inc. 2011.
2. Ehrenstein, G. W. Polymere Werkstoffe; Carl Hanser Verlag, 2011, p. 325.