AbstractPolyvinylidene chloride (PVDC) copolymers are highly crystalline materials used in packaging applications because of their strength and excellent barrier properties. The crystalline moiety (∼40 to 50%) generally melts from 160 to 170°C and the amorphous phaseTgis between 0 and 35°C depending on the comonomer type and level. PVDC is much less thermally stable than PVC and degrades very rapidly in the same temperature range (i.e. above theTm) required to process the material. Added plasticizers are utilized to reduce processing temperatures but at the expense of barrier properties. There is a need to process PVDC sans plasticizer to achieve maximum possible barrier properties in multilayer composite sheet and films. Additives will be discussed that have been shown (in laboratory tests) to delay the fusion of the amorphous phase of unplasticized PVDC until the material temperature nears the crystalline melting point, thus reducing the overall heat history with a minimal effect on other important propert