Estimation of Thermal History of Polymer Using DSC-60 Plus Differential Scanning Calorimeter

Significance of the Topic

Monitoring polymer thermal history is essential for ensuring consistent physical properties and eliminating defects in industrial and recycled plastic products. Differential scanning calorimetry (DSC) offers a non-destructive approach to reveal subtle thermal events.

Study Objectives and Overview

This study presents a method to estimate both the heat treatment temperature and duration of high density polyethylene (HDPE) by analyzing the onset and peak top temperatures in derivative DSC curves.

Methodology

Samples of commercial HDPE pellets were ground into fine particles and subjected to controlled heat treatments:

• Temperature series: 80 °C to 110 °C (5 °C intervals), 10-minute holds
• Time series: at 80 °C for 10, 30, 60, 90, and 120 minutes
• Cooling to 25 °C at −10 °C/min and subsequent DSC scan to 170 °C at 10 °C/min

Used Instrumentation

• DSC-60 Plus Differential Scanning Calorimeter

Main Results and Discussion

Derivative DSC analysis revealed low-temperature endothermic inflections corresponding to prior heat treatments. Key findings:

• Onset temperature in derivative DSC curves correlates linearly with heat treatment temperature (R²>0.999), enabling precise estimation of treatment temperature.
• Peak top temperature shifts upward with longer treatment times at 80 °C, showing a strong linear relationship (R²≈0.99), allowing estimation of treatment duration.

Benefits and Practical Applications of the Method

This approach allows detection of minor thermal events undetectable in standard DSC scans. It is valuable for quality control, failure analysis, recycling verification, and process diagnostics in polymer manufacturing.

Future Trends and Opportunities

Potential extensions include application to various crystalline polymers, integration with modulated DSC and advanced data analytics for predictive process monitoring, and real-time inline thermal history assessment.

Conclusion

The derivative DSC method provides a sensitive, quantitative means to reconstruct the thermal history of HDPE, correlating onset and peak top temperatures with treatment conditions and supporting enhanced polymer quality assurance.

Reference

1. Kobunshi Ronbunshu, Vol. 67, No. 9, pp. 511–515 (2010)