Molecular dynamics simulations have been used to prepare semicrystalline samples of linear polyethylene (PE) using the anisotropic united atom (AUA4) model. The initial configurations of the simulations were obtained by controlled melting of the pure crystalline system and a unique re-connection method between chain segments in the intercrystalline regions. Systems containing two crystalline slabs and two large intercrystalline regions are built with different defects, introduced to mimic the structure of real PE systems, namely: bridging chains connecting two different crystalline slabs, re-entrant chains emerging and re-entering into the same crystalline slab, and free chains. We observe large structural differences between the different systems. We show that average and local density depend on defect types which in turn affect the dynamical properties. This explicit simulation of a crystalline amorphous interfacial region thus gives a possible picture of intercrystalline regions that can serve to understand and predict penetrant gases transport in such materials. (C) 2013 Elsevier Ltd. All rights reserved.