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 rea son they occupy a place of prominence in the plastic packaging industry. Un fortunately, these polymers undergo facile thermally-induced degradative de hydrochlorination at modest temperatures. To permit the processing of these materials at 150-170 degrees C an effective stabilization package is requi red. One component of any stabilization system is a passive base to absorb evolved hydrogen chloride which can form accelerative Lewis acids by intera ction with metallic surfaces of process equipment. The availability of a ne w 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/meth yl acrylate (5 mol%) copolymer have been examined by thermogravimetry to as sess the utility of these materials as potential stabilizers for vinylidene chloride polymers. (C) 2000 Elsevier Science B.V. All rights reserved.