Characterization of Naturally Weathered Polypropylene Plates

Abstract

The natural outdoor ageing of thick plates of isotactic polypropylene is investigated. Different techniques (infrared spectroscopy, thermal analysis, scanning electron microscopy, and mechanical tests) are used in order to obtain a comprehensive view of the modifications occurring during the environmental ageing. The degradation of the material is ascribed to a morphology variation, with relevant changes in the crystallinity percentage. At any exposure time, the degree of oxidation shows a marked decrease while passing from the material near to the surfaces to the material of the inner regions. This suggests that other chemical reactions different from oxidation are responsible for the polymer degradation in the inner region of the plates.

Keywords:

• infrared spectroscopy
• thermal analysis
• isotactic polypropylene
• natural degradation