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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

BIOLOGIC DEGRADATION OF RUBBER GASKETS USED FOR SEALING PIPE JOINTS

DEGRADATION HAS BEEN REPORTED OF NATURAL RUBBER GASKETS USED FOR SEALING PIPE JOINTS OF ASBESTOS-CEMENT PIPES IN THE NETHERLANDS. THE DEGRADATION WAS CAUSED BY THE ATTACK OF SPECIFIC BACTERIA OF THE GENUS STREPTOMYCES. THE ABILITY OF THESE ORGANISMS TO CONSUME THE HYDROCARBON OF VULCANIZED NATURAL RUBBER WAS CONFIRMED BY PURE CULTURE TESTS. SYNTHETIC RUBBER COMPOUNDS PROVED TO BE RESISTANT, WITH THE EXCEPTION OF SYNTHETIC POLYISOPRENE, THE HYDROCARBON COMPONENT OF NATURAL RUBBER. DICKENSON'S HYPOTHESIS IS THAT THE BIOLOGIC DEGRADATION OF THE RUBBER MUST BE PRECEDED BY A NORMAL OXIDATION PROCESS THAT BREAKS THE LONG HYDROCARBON CHAIN INTO SHORTER MOLECULES WHICH THEN MAY BE CONSUMED. BACTERIOLOGIC WORKS SHOW THE UTILIZATION OF VARIOUS ALIPHATIC HYDROCARBONS BY BACTERIA. A REPRESENTATIVE NUMBER OF AMERICAN GASKETS WERE TESTED WITH REGARD TO THEIR RESISTANCE TO BIOLOGICAL ATTACK, UNDER EXACTLY THE SAME CONDITIONS THE DUTCH RINGS WERE TESTED. NONE OF THE SYNTHETIC COMPOUNDS, INCLUDING NITRILE, NEOPRENE, ETHYLENE- PROPYLENE AND STYRENE-BUTADIENE RUBBER WAS ATTACKED. THE RESISTANCE OF SYNTHETIC RUBBER COMPOUNDS WAS CONFIRMED. ALL NATURAL RUBBER AND SYNTHETIC POLYISOPRENE RUBBERS WERE ATTACKED. THE THREE MIXED COMPOUNDS OF NATURAL RUBBER OR POLYISOPRENE WITH ADDED SYNTHETIC ELASTOMER STYRENE BUTADIENE RUBBER (SBR) ARE ALL VERY RESISTANT. THE RATIO OF NATURAL RUBBER AND SBR IN THESE MIXTURES IS UNKNOWN. THE GREATER RESISTANCE TO BIOLOGIC ATTACK IN THE U. S. MAY BE DUE TO DIFFERENT WATER CONDITIONS.

  • Supplemental Notes:
    • Vol 60, No 9, PP 1070-1076, 3 FIG, 6 REF
  • Authors:
    • Leeflang, K W
  • Publication Date: 1968-9

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  • Accession Number: 00216757
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 31 1994 12:00AM