Research on the Thermal Aging Behaviors of LDPE/TiO₂ Nanocomposites

Abstract

The ability of antithermal aging of LDPE/TiO 2 nanocomposites was investigated through SEM, FTIR, DSC, and dielectric properties in this paper. The results of SEM images showed that the thermal aging had a significant influence on the structure of Pure-LDPE and LDPE/TiO 2 samples. The measurement of FTIR showed that the content of hydroxyl and carboxyl increased with thermal aging, but the time of emerging aging characteristic peaks for the LDPE/TiO 2 samples was delayed. The DSC measurement indicated that filling TiO 2 nanoparticles changed the crystallization behavior of LDPE, played a role of heterogeneous nucleation during the process of recrystallization, and improved the crystallinity of LDPE/TiO 2 . Similarly, the aged LDPE/TiO 2 samples had lower permittivity and dissipation factor compared to the aged Pure-LDPE samples. All the results had indicated the LDPE/TiO 2 samples had the significant ability of antithermal aging, especially the LDPE/TiO 2 -0.5 samples with good dispersion of nanoparticles. A new model was proposed to illustrate the antithermal aging behaviors of LDPE/TiO 2 samples, which shows that the TiO 2 nanoparticles play a role of "crosslinking points" between LDPE molecular chains, increasing the density of crystal structure and reducing oxygen diffusion into materials to break molecular structure.

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