A new series of functional polyethylene (PE) with ester pendant (-COOR, R = methyl, ethyl, n-propyl, n-butyl, n-octyl, n-dodecyl, n-tetradecyl and n-hexadecyl) on every five main chain carbons were prepared via ring-opening metathesis polymerization (ROMP) of COOR functionalized cyclopentene catalyzed by a ruthenium-based catalyst and subsequent hydrogenation of the ROMP products. High monomer conversions (70-80%) were achieved in all the ROMP reactions. Chain structure, molecular weight and molecular weight distribution (MWD) of the ROMP products and hydrogenated polymers were characterized by H-1, C-13 NMR and GPC, which showed regular distribution of the COOR pendants along the main chain, moderate molecular weight and narrow MWD. Thermal properties and side chain crystallization behaviors of the functional PEs were investigated by differential scanning calorimetry (DSC). Glass transition temperature (T-g) of the polymer decreased for nearly 30 degrees C when R of the pendant COOR was enlarged from methyl to n-octyl, and the new polymers showed lower melting temperature (T-m), higher side chain crystallinity (X-c) and more precise side chain lamellar crystal thickness (l(c)) as compared with corresponding polyacrylates carrying the same side alkyl. The new polymers exhibited moderate thermal stability. (C) 2017 Elsevier Ltd. All rights reserved.