Thermal stabilization of polypropylene by renewable antioxidants

Kröner R, Kaschta J, Heiduk I, Dorfmüller D, Falk M, Schubert DW (2023)

Publication Language: English

Publication Type: Conference contribution, Abstract of a poster

Publication year: 2023

Event location: Kopenhagen DK


The thermal stability of recycled polypropyl-
ene should be increased by using renewa-
ble stabilizers known as antioxidants. These
chemical compounds delay the degradation
and aging of polymers by offering a hydrogen
atom to the radical generated during thermal
decomposition, so that the radical does not
react with the polymer chain [1].
In this work the use of Irganox 1010 (industry
standard), lignin and α-tocopherol (vitamin E)
in polypropylene is investigated [2-4]. To assess
the effectiveness of the stabilizers, the oxidation
induction time (OIT) is determined according
to standard (EN ISO 11357-6) [5]. The oxidation
induction time is the time a polymer can resist
at 200 °C until degradation occurs after the
change from nitrogen to oxygen atmosphere.
The objective is to increase that time to more
than 10 minutes. By adding different amounts
of antioxidant, a critical concentration c* is cal-
culated at which the objective is achieved.
A linear relationship between concentration
and thermal stability is found for all systems,
except for the addition of α-tocopherol. The
highest thermal stability is achieved by α-to-
copherol and α-tocopherol succinate, whose
structures are formed on the basis of BHA
(2, 6-di-tert-butyl-4-methoxyphenol) instead of
BHT (2, 6-di-tert-butyl-4-methylphenol), as it is
the case for the other stabilizers [4]. Compared
to the industry standard (Irganox 1010) the
efficiency of α-tocopherol is ten times higher
in the relevant concentration level, making Vi-
tamin E the most suitable antioxidant found in
this research. The wood component lignin also
shows good stabilization effects, but requires
the tenfold concentration c* than Irganox 1010.
Furthermore, the stabilized samples are ana-
lysed with regard to their rheological proper-
ties. At a temperature of 250 °C, that is equal
to the processing temperature in the industry,
degradation occurs during the measurement,
so the unstabilized sample (pure PP) shows
a lower viscosity compared to the stabilized

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How to cite


Kröner, R., Kaschta, J., Heiduk, I., Dorfmüller, D., Falk, M., & Schubert, D.W. (2023, May). Thermal stabilization of polypropylene by renewable antioxidants. Poster presentation, Kopenhagen, DK.


Kröner, Richard, et al. "Thermal stabilization of polypropylene by renewable antioxidants." Kopenhagen 2023.

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