ACRYLONITRILE-BUTADIENE-STYRENE.

Abstract

Results of an experimental investigation are presented which show that embrittlement of ABS occurs as a result of oven aging in the temperature range of 50 degree C to 90 degree C even in the absence of oxidation. In experiments, injection and compression molded tensile bars, ASTM D-638, type I, were prepared from commercially available ABS. Samples were aged in both an air and a nitrogen atmosphere in order to separate the oxidative and thermal effects. IR spectra of the surface of the tensile bars were obtained as a function of aging time by use of a frustrated multiple internal reflection (FMIR) attachment to an IR spectrophotometer. Differential scanning calorimetry measurements were made at 10 degree C/min on samples cut from the tensile bars. Tensile properties were obtained in accordance with ASTM D-638-72 except that an extensometer was not used. A gage length of 2. 5 inches was employed for calculating ultimate elongation. The embrittlement is believed to be caused by annealing of the glassy phase.