Polypropylene (PP) based materials is one of the most versatile plastics with wide applications in various aspects of daily life because of lower production cost and environmental impact. Polymer/inorganic nanocomposites have opened new application areas of polymer material. However, low light and thermal stability is the problems for the long-term usage of PP. PP composite promotes volatilization of the antioxidant from the filler/matrix interface. Therefore, the addition of various antioxidants is essential in order to obtain practical lifetime. The efficiency and the reduction of physical loss of antioxidants, such as volatilization and leaching from PP matrix are important. This study focused on a long-term stability of PP materials, which strongly depends on the lifetime of antioxidants. It was found that the lifetime of the PP and PP nanocomposites (PP/SiO2) is greatly elongated by the addition of hyperbranched bis-MPA polyester-16-hydroxyl, generation 2 (G2-HBP) or hyperbranched bis-MPA polyester-64-hydroxyl, generation 4 (G4-HBP) as a molecular capsule of antioxidants . HBP significantly suppressed the volatilization of the antioxidants without compromising the mobility of antioxidant. This efficiency strongly depends on the generation of HBP. The addition of HBP in the presence of SiO2 elongated the oxidation induction time (OIT) more than that in the absence of SiO2, indicating the high efficiency for PP nanocomposites. HBP might be grafted to SiO2 surfaces and highly dispersed in PP matrix. The merit of this method is to improve the efficiency of the conventional antioxidants, which makes the synthesis new antioxidants unnecessary.

Antioxidants encapsulation for long-term stabilization of polypropylene materials by coexisting with hyperbranched polyester

248th National Meeting (2014)

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