Compound Mechanism of the Endo-Exothernic and Exo-Endothermic ± Balanced Blowing Agent

The effects of auxiliary blowing agent were investigated. Based on the results, new combined blowing agents were studied. The difference between the kinetics and thermodynamics of decomposition of the typical blowing agents were compared. Compared with the typical single blowing agents, the new combined blowing agents had the below characteristics: (1) The endothermic enthalpy equals exothermic-enthalpy; (2) The rate of gas evolution of the combined blowing agents is relatively rapid but not abrupt to form more regular and small cell structure; (3) They comprised of blowing agent, nucleation agent and blowing auxiliary agent. The blowing fratures in actual processing by Brabender extruder were verified. The data and the results are valuable to flowing research and can provide the theoretical basis for producing cellular PVC material by extruding.