Ethylene Based Copolymers with Tunable Content of Polymerizable Hindered Phenols as non-Releasing Macromolecular Additives

Four comonomers bearing a highly efficient phenolic antioxidant unit and different methylene spacers between the aromatic ring and the double bond have been prepared and tested in copolymerization with ethylene using metallocenebased catalysts. The possibility of obtaining a " masterbatch" suitable for melt blending with commercial polyolefins has been evaluated by modifying: (i) the structure of the functionalized comonomer, (ii) the kind of catalyst, and (iii) the polymerization conditions. Characterization of monomers and copolymers was accomplished by using 1H and 13C NMR, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). Using the comonomer with the longest methylene spacer between the aromatic ring and the double bond, and TdC-(EBTHI)ZrCl2 as catalyst, adjustable amounts of the antioxidant moiety can be incorporated into the polyethylene chains. TGA analysis carried out on some of the copolymers containing the antioxidant group showed no oxygen uptake before decomposition.