A Kinetic Study on the De-Crosslinking and Decomposition of Silane-Cross-Linked Polyethylene in Supercritical Methanol

Abstract

De-crosslinking of silane-cross-linked polyethylene (S-XLPE) in supercritical methanol was investigated. Changes in gel content and molecular weight with reaction temperature and reaction time were analyzed in a batch reactor, and kinetic parameters were calculated from the experimental data. The reaction time for de-crosslinking shortened as the reaction temperature increased and the complete de-crosslinking of S-XLPE was achieved at 320 °C and 20 min. The de-crosslinking rate of S-XLPE fit well with the first order reaction model. In addition, the molecular weight of de-cross-linked polyethylene (DXPE) decreased further as reaction temperature and reaction time increased when the reaction temperature exceeded 360 °C relative to that of the original polyethylene before being cross-linked. The decreasing molecular weight trend also fit well with the first order reaction model.

Structures and properties of waste silicone cross‐linked polyethylene de‐cross‐linked selectively by solid‐state shear mechanochemical technology

“…and Table . The cross‐linking process of Si‐XLPE materials could introduce the —Si—O—Si— and —C—Si— bonds, which were more prone to thermal decomposition and could affect thermal stability of materials . Then, the thermal stability of materials could be improved with milling cycles increasing, by which these bonds reduced due to partial de‐cross‐linking.…”

Recent Advances in Cross-linked Polyethylene-based Nanocomposites for High Voltage Engineering Applications: A Critical Review

“…Supercritical water and supercritical alcohol are solvents that can be used to decross-link polymers. Hong et al 121 have studied the kinetics of decross-linking of silane-linked polyethylene in supercritical CH 3 OH. The residual gel content and molecular weight of decross-linked polyethylene at different temperatures and times were evaluated for a better understanding of the kinetic study.…”

Mechanochemical modification of crosslinked low‐density polyethylene: Effect of solid‐state shear pulverization on crosslinks, branches, and chain lengths

“…[14][15][16] Efforts to handle XLLDPE waste in an environmentally responsible manner have been sparse. While earlier work focused on reducing its size for downcycling into a filler material, [15,17] more recent reports included batch pan-milling, [14,18,19] supercritical fluid-assisted reactions in batch and continuous modes, [16,20,21] and ultrasonic melt extrusion [22,23] to chemically or mechanochemically decompose the crosslinks. The development of LDPE vitrimers led to a material with reversible crosslinks.…”