New Method of Impregnating PEI Sheets for the In-situ Foaming of Sandwiches

摘要

A new method is described to make foamable films for the production of in-situfoamed sandwiches. The method consists of placing a polymer film in a bath with a swelling agent and, when equilibrium swelling has been reached, placing the film in a bath with a second liquid. If the liquids are miscible the swelling agent in the film will be replaced by the second liquid. The polymer used for the research described in this report was polyetherimide and the swelling agent was acetone. Sandwiches were produced with the foamable films made in this manner using ethanool, 1,1,1-trichloroethane and water as blowing agents. Some mechanical properties of these sandwiches were tested.