Accession Number : ADB000996


Title :   Ten-Year Aging of Elastomeric Vulcanizates in Panama, Alaska, and Illinois


Descriptive Note : Technical rept.


Corporate Author : ROCK ISLAND ARSENAL IL GENERAL THOMAS J RODMAN LAB


Personal Author(s) : Bergstrom, Edward W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/b000996.pdf


Report Date : Jul 1974


Pagination or Media Count : 83


Abstract : Vulcanizates prepared from commercially available elastomers, many of which have been introduced since 1955, were exposed outdoors in Alaska; Rock Island, Illinois; and in the Panama Canal Zone to compare the effects of exposure in arctic, temperate, and tropic environments. Aging data collected on pads exposed as long as ten years are presented. The effects of rain forest vs. open sun exposure in Panama are compared as well as the effects of indoor vs. outdoor aging at Rock Island, Illinois. The ozone resistance of numerous vulcanizates was determined by exposures at the three sites, using ASTM D518, Method B, bent loop specimens. The resistance to cracking of numerous polyurethane vulcanizates exposed in Panama was also measured. Results show that aging is generally more severe in Panama than in Alaska or Rock Island, although some vulcanizates exhibit excellent aging resistance at all three sites. Polymeric antiozonants (EPDM) are more effective than chemical antiozonants in protecting SBR, NBR, and NR vulcanizates from ozone attack. Unstressed polyester urethane vulcanizates, even those containing hydrolysis inhibitors, deteriorate rapidly in Panama. Polyether urethane vulcanizates have also begun to show significant deterioration in Panama after seven years, while polyether urethane- urea vulcanizates remain relatively unaffected.


Descriptors :   *ELASTOMERS , *VULCANIZATES , ACCELERATED TESTING , ADDITIVES , AGING(MATERIALS) , ANTIOXIDANTS , ARCTIC REGIONS , COLD WEATHER TESTS , CRACKING(FRACTURING) , DEGRADATION , ELONGATION , ENVIRONMENTAL TESTS , EXPOSURE(GENERAL) , GRAPHS , MECHANICAL PROPERTIES , OXIDATION RESISTANCE , OZONE , POLYESTER PLASTICS , POLYMERS , POLYURETHANE RESINS , TABLES(DATA) , TEMPERATE REGIONS , TENSILE PROPERTIES , TROPICAL REGIONS , TROPICAL TESTS , UREIDES


Subject Categories : Elastomers and Rubber


Distribution Statement : APPROVED FOR PUBLIC RELEASE