One reason of the discrepancy could be the change in CPEM shape during swelling, which cause [k.
The CPEMs were obtained using a method developed by White , whereby crosslinked polyethylene (XLPE) insulation layers were systematically stripped from recycled high-voltage distribution cable.
A TA Instruments DSC 2920 (TA Instruments, New Castle, Delaware) was used to study the thermal properties and crystallinity of CPEMs in squalane.
Swelling experiments were carried out on CPEMs and thin XLPE strips immersed in squalane to determine the particle volume fraction as a function of temperature.
At temperatures below the transition point, the CPEMs are thought to remain in a collapsed conformation, held together by crystalline regions within the network up until the melting point, as indicated by the DSC data presented in Fig.
The change in linear size of the CPEMs as it swells was converted into a particle volume expansion ratio [[epsilon].
In addition, melt-blending polyethylene in a polystyrene matrix with the addition of a surfactant  followed by exposure to an electron beam to crosslink them can produce CPEMS of smaller size, and possibly free of surface terminal chains.