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An investigation of mechanisms of synergistic interactions in PVC stabilization
Author(s) -
Briggs G.,
Wood N. F.
Publication year - 1971
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1971.070150103
Subject(s) - zinc , chemistry , cadmium , chlorine , barium , inorganic chemistry , hydrogen chloride , polymer , hydrogen peroxide , calcium , polymer chemistry , cadmium chloride , stoichiometry , organic chemistry
Abstract Synergism in poly(vinyl chloride) stabilization has been studied by measuring rates of hydrogen chloride evolution from samples of polymer in the presence of stabilizers in di‐(2‐ethylhexyl) phthalate solution in an inert atmosphere. Barium, cadmium, calcium, and zinc laurates, when used alone, allow escape of hydrogen chloride well before stoichiometric uptake is achieved, whereas synergistic mixtures of calcium–zinc and barium–cadmium laurates absorb almost the theoretical quantity of hydrogen chloride. Cadmium and zinc laurates replace labile chlorine atoms in the polymer backbone by ester groups, reducing formation of long polyene sequences: barium and calcium laurates delay the formation of cadmium and zinc chlorides, apparently by reconverting them into their respective laurates. Polyols function by forming complexes with the prodegradant cadmium and zinc chlorides, but contrary to popular belief phosphites possess little activity in this respect. Instead, they slow down the rate of polymer degradation by removal of labile chlorine atoms, by reaction with hydrogen chloride, and by peroxide decomposition.