Polymeric antioxidant for long-term stabilization of polypropylene

The present work aimed to preparation of a new polymeric antioxidant for polypropylene (PP), which has no tendency toward migration from the polymer. Accordingly, a diacid (phenylmalonic acid), which has a labile hydrogen atom and can act as a hydrogen donor antioxidant, was polymerized with 1,4- phenylenediamine to render a polyamide. Occurrence of the reaction was confirmed by FT-IR spectroscopy, differential scanning calorimetry (DSC), gel permeation chromatography. The synthesized polyamide was mixed with PP and its uniform distribution in the matrix was verified by yellowness index measurements. Oven ageing experiments followed by FT-IR spectroscopy revealed that the synthesized antioxidant amends thermo-oxidative stability of the polymer in solid state with an eminent efficiency which is even better than that of SONGNOX 1010. Furthermore, its remarkable stabilization activity was proved by DPPH method. Finally, the synthesized polyamide’s potential, as an efficient antioxidant for PP, especially in the long-term stabilization, was assigned to presence of two different hydrogen donor groups, i.e. allylic and amine hydrogen atoms, in themolecular structure of the new antioxidant.

Keywords:

Polymerized Antioxidant , Degradation Polypropylene , Long term stabilization