myo-Inositol as a Biobased Multifunctional Additive: Simultaneous Enhancement of Thermo-Oxidative Stability and Crystallization Kinetics in Vitamin E Stabilized Polypropylene

Polypropylene (PP) combines excellent mechanical properties with cost-effectiveness, yet its practical applications are hindered by poor thermo-oxidative resistance and slow crystallization kinetics. While conventional antioxidants and nucleating agents can mitigate these issues, increasing safety concerns over synthetic additives have spurred interest in natural alternatives. However, natural antioxidants such as vitamin E (VE) often exhibit inadequate stabilization at low loadings, and few industrially available biobased nucleating agents were developed. Here, we reported that myo-inositol (Ins), a bioderived compound, acted as a dual-functional additive, simultaneously improving both the thermo-oxidative stability and crystallization behavior of VE-containing PP. Incorporating 0.2 wt % Ins into PP stabilized with 0.1 wt % VE dramatically extended the oxidation induction time from 7.5 to 45.3 min, indicating strong synergistic antioxidant activity. Furthermore, Ins enhanced crystallization kinetics, increasing the peak crystallization temperature by 5.4 °C (10 °C/min cooling rate) and reducing the half-crystallization time by 69% during isothermal crystallization at 120 °C compared to VE-only PP. The dual role of Ins was attributed to its function as a metal chelator and a heterogeneous nucleation agent, offering a sustainable strategy for high-performance PP modification.