ARTIFICIAL WEATHERING DEVICES

ARTIFICIAL WEATHERING MACHINES WERE STUDIED AT THE NATIONAL BUREAU STANDARDS INSTITUTE FOR APPLIED TECHNOLOGY TO DETERMINE THE RADIATION CHARACTERISTICS OF THE DEVICES. SUCH CHARACTERIZATION SHOULD MAKE POSSIBLE BETTER SIMULATION OF SOLAR RADIATION WHICH IS CONSIDERED ONE OF THE MOST IMPORTANT FACTORS IN THE DETERIORATION OF POLYMERS. DEGRADATION OF POLYMERS EXPOSED TO WEATHER IS CAUSED PRIMARILY BY SOLAR RADIATION (ULTRA, VISIBLE, INFRARED) TEMPERATURE, WATER, AND OTHER ATMOSPHERIC CONSTITUENTS. THE THREE MACHINES INVESTIGATED ARE A XENON-ARC DEVICE AND TWO DIFFERENT TYPES OF CARBON ARC DEVICES. THE XENON-ARC DEVICE USED HAS A 6 KILOWATT HIGH-PRESSURE, WATER-COOLED LAMP WITH PYREX JACKETS. THE FIRST CARBON-ARC DEVICE USES 3 CORD CARBONS, ONE AS THE UPPER ELECTRODE AS TWO AS THE BOTTOM, ALL OF WHICH ARE ENCLOSED IN A BELL-SHAPED GLOBE. THE SECOND CARBON-ARC DEVICE USES 3 PARIS OF CARBON ELECTRODES, BRINGING ONE PAIR AT A TIME AND AUTOMATICALLY SHIFTING FROM ONE PAIR TO ANOTHER AS THE CARBONS ARE CONSUMED. THE CURVES FOR IRRADIANCE AT THE SAMPLE DRUM NORMAL TO THE CENTER OF THE ARC WERE PLOTTED FOR TYPICAL ONE-HOUR PERIODS FOR THE THREE ARTIFICIAL WEATHERING DEVICES STUDIED. THE FLAT CURVE OF IRRADIANCE FROM THE XENON-ARC FOR THIS PERIOD CONTRASTS SHARPLY WITH THE IRREGULAR CURVES OBTAINED FOR BOTH CARBON ARCS. THE CHANGE IN IRRADIANCE WITH SAMPLE HEIGHT IN THE DRUM FOR THE CARBON AND XENON ARCS, IN THE PLANE OF THE SAMPLE DRUM PARALLEL TO THE ARC, WAS DETERMINED BY MOVING THE SENSOR. ALL THREE DEVICES HAD A MAXIMUM IRRADIANCE NEAR THE CENTER OF THE DRUM. THE MAXIMUM IRRADIANCE FOR XENON-ARC WAS ABOUT 2.1 TIMES THAT OF THE FIRST CARBON-ARC. THIS INTENSITY FACTOR CAN BE IMPORTANT IN THE ACCELERATION OF DEGRADATION OF POLYMERIC MATERIALS.

  • Supplemental Notes:
    • Vol 52, No 7, PP 148-149, 3 FIG
  • Corporate Authors:

    National Bureau of Standards

    Department of Commerce, Office of Technical Publications
    Washington, DC  USA  20234
  • Publication Date: 1968-7

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Filing Info

  • Accession Number: 00217017
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 5 1970 12:00AM