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The interaction of hydrogen sulfide with lead‐ and barium–cadmium–zinc‐stabilized poly(vinyl chloride)
Author(s) -
Graedel T. E.,
Franey J. P.,
Starnes W. H.,
Hische D. C.,
Warren P. C.
Publication year - 1979
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.1979.070230617
Subject(s) - vinyl chloride , barium chloride , chemistry , zinc , polymer , inorganic chemistry , barium , sulfide , hydrogen sulfide , polymer chemistry , nuclear chemistry , sulfur , organic chemistry , copolymer
Poly(vinyl chloride) polymers stabilized with tribasic lead sulfate discolor upon exposure to hydrogen sulfide gas as a result of lead sulfide formation. The discoloration occurs for samples in both cord and sheet forms and is shown to be a function of total H 2 S exposure, reaching a limiting value that is determined by the amount of lead stabilizer used in the polymer formulation. The permeation and diffusion constants for H 2 S through PVC stabilized with tribasic lead sulfate and with a liquid Ba–Cd–Zn formulation are found to be P Pb = (6.0 ± 0.2) × 10 −9 , P BaCdZn = (5.2 ± 0.2) × 10 −9 (both in cm 3 gasċcm film/cm 2 areaċsecċcm Hg), D Pb = (1.3 ± 0.2) × 10 −7 cm 2 /sec, and D BaCdZn = (6.4 ± 0.6) × 10 −8 cm 2 /sec, all measured at 21°C. The stabilizing efficiencies of the formulations were assessed by HCl evolution measurements, which show that exposure to H 2 S decreases the initial polymer stability for both Pb‐stabilized and Ba–Ca–Zn‐stabilized formulations. Protection of stabilized PVC formulations from diffusing hydrogen sulfide is thus advisable for long‐term stability as well as for color integrity.