Abstract: This paper presents a study on the effect of segment structure on the compatibility and dynamic mechanical damping properties of multiblock copolymer networks. A series of copolymer networks with various segment structures which dampes mechanical vibration over a temperature range of 50 degrees were prepared from vinyl-terminated oligomer as soft segment and vinyl polymers as hard segment, respectively. Somel soft and hard segments in copolymer networks were found to be semicompatibile and many of the copolymer networks based on these formulations resulted in tanδ>1.75 over the desired temperature range.