Local flaws in permeation reducing barrier layers

Abstract

One of the concerns in designing a plastic fuel tank is to make the surface of the container such that it reduces the permeation of fuel. In order to improve the barrier properties of the surface, the inner surface is coated with appropriate thin barrier layer. This is often done by blow molding process. The process has local flaws: many small patches do not get covered by the thin barrier material. These “holes” have been observed by Mark Nulman and modelled by Giuseppe Rossi [1], both from Ford Motor Company. On March 5, 1993 Rossi described the model, and presented results in case of circular holes. He also posed the problem of studying the effect of general shaped “holes” and general distribution of “holes” in the inner surface of the container on the imperbeability of the surface of the container.