Polyethylene containing antioxidant moieties exhibiting high thermal-oxidative stability for high temperature applications

A new class of polyethylene-bonded antioxidants (PE-HP), containing several hindered phenol (HP) groups located along the polymer chain, has been prepared and investigated in this paper. The homogeneously distributed HP groups not only provide polymer stability but also form a completely polymer network under elevated temperatures. In a TGA comparative test, the PE-HP copolymer with 1.1 mol% HP concentration demonstrates no weight loss after heating at 190 °C in air for 1000 min, while the commercial HDPE exhibits weight loss within 100 min. A standard ASTM oxygen induction time (OIT) test also shows heat flow to commercial HDPE after 15 min at 190 °C in air, while the PE-HP copolymer with 1.1 mol% HP groups shows a complete flat OIT line up to 230 min, without any detectable onset heat flow into the sample. This new PE-HP copolymer shall expand HDPE application to high temperatures (>150 °C).