The impact of high surface area magnesium hydroxide on the stability of vinylidene chloride copolymers

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°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.