Role of Higher-Order Structures on the Degradation and Stabilization of Polypropylene-Based Materials.

It is known that the stability of polypropylene (PP)-based materials is greatly affected by their higher-order structures. In this paper, we examined the influences of spherulite structure and inorganic filler on the dispersion of stabilizers and the degradation spreading with the aid of IR microscopy. It was found that stabilizers tend to concentrate outside of spherulite structure, and that such a heterogeneous dispersion became more prominent with increasing spherulite size. Oxidative degradation concentrated at chemically and mechanically weak spherulite borders, and was faster for larger spherulites. The addition of inorganic filler promoted the volatilization of stabilizers from poorly connected interfaces between PP and filler, thus reducing the lifetime of PP. In this way, the present paper describes the significance of higher-order structures and interfaces for the degradation and stabilization of PP-based materials. [ABSTRACT FROM AUTHOR]