Developments in Chemical Expansion Systems for Use in Cellular Polymers

This paper illustrates the increasing range of end applications for azodicarbonamide and the subsequent modifications necessary, both physically and chemically, to ensure its satisfactory performance. Physical modifications of azodicarbonamide to satisfy performance requirements in the plastisol area are detailed, together with the development of azodicarbonamide blends, to modify the decomposition mechanism, eliminate undesirable decomposition residues, and ultimately, modifications in the production of azodicarbonamide to satisfy the performance requirements for use in chemically crosslinked polyolefin foams. The area of high temperature expansion systems, which do not liberate ammonia as part of their gaseous decomposition products, is also discussed relevant to their use in engineering thermoplastics.