Study on Diffusion Behavior of Crosslinking Byproducts of Semiconductive Layer in Polypropylene Blends

In this paper, the possibility of ethylene-butyl acrylate copolymer (EBA) as the inner semiconductive material of PP cable is proposed. The diffusion behavior of related byproducts in PP/PBE blends is evaluated. The PP/propylene-based-elastomer (PP/PBE) and EBA-based semiconductive films were prepared, and the dual-layer samples were treated at different temperatures (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 0, 5 0, 7 0, 9 0}{ }^{\circ} \mathrm{C}$</tex>) and DC electric field (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3,5,7,10 \text{kV} / \text{mm}$</tex>) for 2 h. The chemical structure of the samples was characterized by Fourier transform infrared spectroscopy (FTIR). Moreover, the bidimensional diffusion behavior of byproducts was simulated. The results of the FTIR experiments showed that with the increase of temperature and electric field strength, the carbonyl index (CI) of the materials increased. The simulation results showed that the reduction rate of the byproduct concentration slowed down over time, and the maximum residue of byproducts was retained near the inner semiconductive layer under various conditions.