Investigating the Impact of Grafted Molecule Types on Frequency Domain Spectroscopy of Polypropylene Insulation

Thermoplastic insulation materials represented by polypropylene (PP) have become an important direction for future research on cable insulation materials. To develop high performance PP cable insulation materials, the Havriliak-Negami (H-N) model is used to study the impact of grafted molecule types on frequency domain spectroscopy (FDS) of PP insulation in this paper. Research results demonstrate that PP grafted with the irganox 3052 effectively scavenges free radicals within the material, and increases its oxidation induction time (OIT), thus enhancing the thermal stability of PP. Both the voltage stabilizer DA and the irganox 3052 can increase the barrier height
$(E_{\delta})$
for the thermionic migration in PP. PP-g-3052 exhibits a larger
$E$
δ
compared to PP-g-DA, enabling better suppression of thermionic migration and consequently reducing the thermionic polarization. Concurrently, the relationship between conductivity activation energy
$(E_{\sigma})$
and
$E_{\delta}$
is further studied, with consistent changes observed in both. PP-g-3052 possesses the largest
$E_{\sigma}$
, exerts the strongest inhibitory effect on carrier migration, and more effectively enhances the insulation properties of PP.