Study on Formation Mechanism of Thermooxidative Aging Protection Difference Among Nanoparticles in Low Density Polyethylene

In this paper, the thermooxidative aging protection ability of MgO, ZnO and SiO
₂
nanoparticles for low density polyethylene (LDPE) was compared by experiments. The formation mechanism of thermooxidative aging protection difference among nanoparticles in low density polyethylene was revealed by molecular dynamics simulation. Research indicates that MgO has the strongest protective effect on thermooxidative aging of LDPE, followed by ZnO, and SiO
₂
is the weakest. One of the reasons for the difference in thermooxidative aging protection is that there is interaction energy between nanoparticles and polyethylene molecular chains. The higher the interaction energy, the more regular the distribution of polyethylene molecular chains, the better the structural stability of polyethylene nanocomposites, the stronger the thermooxidative aging protection ability of the corresponding nanoparticles. The another reason is that the presence of particles will reduce the diffusion rate of oxygen in the polyethylene nanocomposites. The oxygen diffusion rate is reduced, the amount of oxygen participating in the thermal aging reaction is reduced, and the development of thermooxidative aging is limited. The more obvious the effect of nanoparticles on oxygen diffusion, the stronger the thermooxidative aging protection ability.