科研之友
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摘要
Recent leak failures in cross-linked polyethylene tubing from several US locations have been studied using microscopy and microscopic spectroscopy. Such failures compromise the use of a material that has been regarded as more environmentally sustainable. The failures appear to be the result of local chemical attack by aqueous chlorine that reacts with the polymer, leading to its oxidation, decrystallization and expansion of its volume. This creates stress fields that lead to chemically induced cracking of the polymer and, eventually, failure of the tubing. Each failure studied in this work was found to be associated with a micro-protrusion in the inside diameter of the tubes; it is proposed that turbulence in the water flow behind the protrusion may accelerate local mechanical and chemical attack of the polyethylene tubing. A simple inspection method is suggested to detect the presence of such protrusions before installation of the tubing.
- 出版日期2017-12
