Abstract: The foaming behavior of PVA influenced by different foaming agents (including the thermal release, thermal absorption, thermal equilibrium and reaction type) was studied, and the foaming samples were processed through the extruding method. The results of differential scanning calorimetry and thermogravimetric analyzer showed that all types of the foaming agents improved the degrees of crystallization and the crystallization temperature of PVA, while the thermal stability of PVA matrix reduced in different degrees. The results of electron microscopy scanner, density spectrometer and mechanical test showed that foamed PVA with the reaction typefoaming agent had more uniform cells and the lowest density, while its mechanical propertits was poor.

Key words: poly(vinyl alcohol), foaming agent, crystallization, thermal stability, cell morphology