Development of Pneumatic Deformability Test of Polylactic Acid Films

Abstract

The aim of the present study is to develop a test method suitable for modelling thermoforming processes and which provides an index that accurately characterises the thermoformability of a film or sheet at a given temperature and pressure. For this purpose, the elevated temperature pneumatic deformability test was considered to be the most suitable. During the test, the film is blown until it tears, which takes only a few seconds. We recorded blowing during the test, and used the images to determine the ascent (k) of the specimens and approach the estimated surface of the deformed specimens with a sphere.