Vinylidene chloride (VDC) copolymers display high barrier to the transport of oxygen, other small molecules, and flavor and aroma agents. For this reason they occupy a place of prominence in the plastic packaging industry. Unfortunately, these polymers undergo facile thermally-induced degradative dehydrochlorination at modest temperatures. To permit the processing of these materials at 150-170 degrees C an effective stabilization package is required. One component of any stabilization system is a passive base to absorb evolved hydrogen chloride which can form accelerative Lewis acids by interaction with metallic surfaces of process equipment. The availability of a new high-surface area magnesium hydroxide offers potential for development as an effective additive for this purpose. Blends of this material and other commercially available magnesium hydroxides with a vinylidene chloride/methyl acrylate (5 mol%) copolymer have been examined by thermogravimetry to assess the utility of these materials as potential stabilizers for vinylidene chloride polymers.