Hyperbranched polyglycerol nanoparticles based multifunctional, nonmigrating hindered phenolic macromolecular antioxidants: Synthesis, characterization and its stabilization effect on poly(vinyl chloride)

Abstract

A facile synthesis of multifunctional hindered phenolic macromolecular antioxidants based on hyperbranched polyglycerol (HbPG) nanoparticles as cores with different molecular weights is reported. The structure of the resulting polymers was verified by 1H NMR and UV–Vis spectroscopies indicating 64–77% antioxidant functionalizations of the hydroxyl groups of the HbPGs. GPC analyses show that polymeric antioxidants with PDI of 1.33–1.66 are formed. DSC and TGA measurements revealed Tg of ∼40 °C and high thermal stability up to ∼300 °C of the multifunctional HbPG-antioxidant conjugates, respectively, confirming that these materials are liquids and stable at usual polymer processing temperatures. The efficiency of the synthesized antioxidants in thermooxidative stabilization of PVC was investigated, keeping in mind that although the importance and wide application of PVC, especially in biomedical fields are incontestable, the utilization of macromolecular antioxidants for the stabilization of PVC has not been examined so far. It was found that the macromolecular antioxidants show similar stabilizing efficiency as the tetrafunctional industrial Irganox1010. Very low extent of leaching of the HbPG-antioxidant from PVC, investigated by extraction tests in both water and hexane, was observed in both extracting agents in contrast to the case of the low molecular weight hindered phenolic antioxidant. Thus, the obtained results confirm the advantages, i.e. high efficiency and highly suppressed leaching, of HbPG-based macromolecular antioxidants in a variety of application fields.