Using chemical blowing agent systems based on azodicarbonamide for producing polyethylene foams

In this work, effect of using different contents and conditions of azodicarbonamide as a blowing agent on final properties and cell morphology of polyethylene-ethyl vinyl acetate foams that produced from expandable granules, was investigated. This granules are made by co current twin extruder with different formulations consist of required additives to polymeric matrix such as blowing agent, cross-linker, nucleating agent andactivator. Then these granules molded to produce suitable foam sheets for preparation test specimens according to their standards.Density, tensile properties, compression strength and cell morphology (shape and size of cells and cell density) of different specimens then measured. From this results the best formulations and conditions for packaging applications (foam with lowest density, highest elongation and optimum compression strength) is obtained. Also the effect of some ingredients in formulation, such as zinc oxide as a blowing agent activator and coated calcium carbonate as a nucleating agent are investigated.