Study on processing-microstructure-properties relationships of extruded profiles

In the present work, a rectangular polypropylene profile was produced under different extrusion conditions, in order to identify the most relevant processing variables determining its microstructure and mechanical properties and to understand the relationships between them. A Taguchi design of experiments technique, considering two levels for each variable (operating conditions), was used to define the set of extrusion runs. The resulting plastic profiles were characterised according to their microstructure and mechanical properties. It was concluded that the most significant processing variable determining the mechanical properties of the extrusion profiles is the extrusion temperature and that the drawdown ratio controls the degree of molecular orientation of the profiles, and therefore, the extension of shrinkage after heating.Fundo Europeu de Desenvolvimento Regional (FEDER