The Chromatogram Series: Polypropylene
Written by: Ulf Nobbmann
Here is an example chromatogram of polypropylene (or sometimes abbreviated as PP), a member of the polyolefins. The run conditions and some results are detailed in the table below.
|Flow Rate [mL/min]||1.000|
|Column Set||2 x HT CLM6210|
|Column Temp (°C)||160.0|
|Injection volume μL||200.0|
|Mw Weight Average [Da]||475,242|
|Sample dn/dc [mL/g]||0.0910|
|Sample IV [dL/g]||2.1299|
This sample of moderate molecular weight polypropylene is analysed on the Viscotek HT-GPC system at 160 °C. The chromatogram shows the excellent stability of the system and the low noise level of the light scattering (LALS) even at this high temperature in trichlorobenzene TCB.
In this data set, the LALS scattering signal (obtained at a scattering angle of only 7º) is used for directly obtaining the molecular weight without any extrapolation. This is particularly useful when ansiotropy begins for large molecular weight polymers.
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