Abstract
The extraction of soluble materials from elastomeric closures has always been a prime concern to the parenteral packaging industry. An improved method for the extraction of soluble aluminum from chlorobutyl rubber closures containing calcined clay filler has been examined. After ashing, samples of raw material and finished product are digested in hydrochloric acid using a steam bath, filtered, and analyzed for percent aluminum by atomic absorption spectroscopy. Since one-third of the rubber formulation consists of calcined clay, and the clay is an aluminum silicate, the theoretical correlation for soluble aluminum in the finished closure examined and its clay filler should be one to three; the closure should contain one-third the amount of soluble aluminum as compared to the raw material. Using the method described, this theoretical one to three correlation is obtained. The effects of the duration and conditions of the extraction were also studied.
- Received December 22, 1982.
- Accepted February 8, 1983.
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