PE-LD and PE-LLD as pellets, PE-HD as a film.
(-CH2 -CH2-)n
Measuring cell: DSC821e with air cooling
Pan: Aluminum standard 40 ul, lid hermetically sealed
Sample preparation: PE-LD: Disk of 9.796 mg cut from pellet
PE-LLD: Disk of 8.128 mg cut from pellet
PE-HD: Disk of 10.314 mg punched from film
DSC measurement: Heating from 30 to 108°C at 10 K/min
Atmosphere: Static air
Note: Two values can be used to characterize the peak temperature: the extrapolated intersection point of the inflection tangents, and the maximum of the DSC curve. The extrapolated peak temperature is not influenced so much by the arbitrary shape of the peak where random noise may cause the actual maximum to differ slightly from run to run, leading to an irreproducible <<peak temperature>>. For this reason the reproducibility of the extrapolated value is usually better.
The melting peaks are typical for the different PE qualities with their distinctive peak temperatures.
The peak temperature of the DSC melting curve is the most frequently determined property of semicrystalline polymers. It is the key parameter for processing and serves generally for identification.
PE, Characterization by Peak Temperature | Thermal Analysis Application No. HB200 | Application published in METTLER TOLEDO TA Application Handbook Thermoplastics