Abstract: The current research works in five types of polyolefin foams was reviewed, including cross-linked, copolymerization-modified, wood-polyolefin composites, flame retardant, and additive enhanced foam materials. It was suggested that the future formulations and processing research works should be carried out in the crossover region of above five types.

Key words: Polyolefin, polyetheylene, Modification, foaming