PE-HD, Characterization by Conversion Curves - METTLER TOLEDO

PE-HD, Characterization by Conversion Curves

Sample

Lupolen 4261 pellets and a molded part said to be Lupolen 4261

 

Conditions

Measuring Cell: DSC821e with air cooling

Pan: Aluminum standard 40 ul, pierced lid

Sample preparation: Disks of approx, 5.0 mg cut from pellet or part

DSC measurement: Elimination of thermal history: 25 to 200°C at 10 K/min, then cooling at 5 K/min. Actual measurement: second heating from 25 to 200°C at 10 K/min

Atmosphere: Nitrogen 50 cm3/min

Evaluation

Interpretation

The melting behavior is characterized by the heat of fusion, the peak temperature and the peak width at half height (all 3 values together) or by the conversion curve. The conversion curve, also called the fraction melted, is a measure of the percentage of crystallites that has melted at the particular temperature. It can be presented in a tabular or graphical form. In contrast to the degree of crystallinity, conversion is a relative value and is therefore practically independent of weighing uncertainties. The balance used for this work had a resolution of 0.1 mg. An uncertainty of 0.3 mg can for example lead to a 6% error in the calculated value of the heat of fusion and hence in the degree of crystallinity. 

 

Conclusion

The melting behavior of the two samples is similar. The main difference is seen in the heat of melting. The crystallization behavior of the samples is compared on the next page.

 

PE-HD, Characterization by Conversion Curves | Thermal Analysis Application No.HB202 | Application published in METTLER TOLEDO TA Application Handbook Thermoplastics